Komagataeibacter genus in terms of their specific physical, physico-chemical, and mechanical properties. Herein, the aim was to choose the most suitable microorganisms producing cellulosic materials with the greatest potential for the fabrication of bio-inspired nanocomposites. The selection was based on three main steps, starting from the evaluation of BNC biosynthetic efficiency with and without the addition of ethanol, followed by the assessment of mechanical breaking strength, and the physical parameters  of the obtained biological materials. Ultimately, based on the performed screening procedure, three efficiently growing strains (K. hansenii H3 (6Et), K. rhaeticus K4 (8Et), and Komagataeibacter sp. isolated from balsamic vinegar (12Et)) were chosen for further modifications, enabling additional cellulose functionalization. Here, supplementation of the growth medium with five representative polymeric compounds  led to significant changes in BNC properties, especially dye loading abilities, mechanical strength, and water adsorption/retention capacities. The resulting nanocomposites can be potentially useful in various fields of medicine and industry, and in the future, they may become a practical and cost-effective competitor against commercial biomaterials currently available on the market.This article presents a comparative analysis of bacterial cellulose membranes synthesized by several strains of the  Microbiologically synthesized cellulose  is a natural and versatile biopolymer of biologic origin, displaying a high-purity and an extraordinary biocompatibility that can be used either alone or in combination with other ingredients, such as polymers and nanoparticles, to vary its structure and function . Among oKomagataeibacter strains (formerly Gluconacetobacter and Acetobacter), have been already recognized to be one of the most efficient BNC synthetizing microorganisms. The main source of carbon for most strains is glucose , but some strains can efficiently grow also on such substrates as fructose or sucrose , glycerol , lactic acid, and even on various industrial food wastes [K. xylinus E25, K. xylinus subsp. sucrofermentans BPR3001A, and K. rhaeticus K3 was found to increase the efficiency of cellulose synthesis, while in the case of strain K. hansenii 53582, the efficiency of biosynthesis was found to be downregulated [K. xylinus E25 that the addition of ethanol is an additional source of energy, while at the same time it reduces the conversion of glucose to the by-product, gluconic acid [Cellulose producing bacteria have been isolated from various environments  that highly affect the optimal cultivation conditions, such as pH, temperature, and carbon source . Komagatd wastes ,14,15,16egulated ,18,19. Inic acid .Komagataeibacter strain and the culture conditions used during cultivation, the obtained cellulose membranes differ in properties such as thickness; the content of dry cellulose and exopolysaccharides (EPS), which are hardly soluble in water; fiber density; pellicle flexibility; water-binding capacity; the degree of polymerization; and the crystallinity index [Komagataeibacter genus in terms of the selection of the most appropriate cellulose producing strain with the greatest potential as a biological material for the food and medical industry. These membranes show properties suitable for the formation of nanocomposites with other biomolecules that significantly changes the properties of chemically inert cellulose and opens new applications for this biomaterial. This approach also gives the possibility of further modification of the obtained composites, enabling additional functionalization in selected directions.Depending on the ty index ,20,21,22ty index ,21,23. IKomagataeibacter strains for the production of BNC membranes, all the available 13 producing strains, listed in the Table 1, were first assessed for biosynthetic efficiency. At the same time, the membranes obtained during the cultivation were analyzed for basic parameters such as elongation at break and tensile strength. The combination of these factors constituted the first basis for the selection of strains for further analyses.In order to choose the most adequate The thirteen cellulose producing strains were cultivated with and without the addition of ethanol, in order to verify the influence of this agent on the BNC production yields. Among all of the cultures, one underwent contamination  and no cellulose was obtained. This strain, therefore, was excluded from further experiments. The rest of the results are presented in This second stage of bacteria selection was aimed at choosing BNC-synthesizing strains characterized by the best mechanical strength parameters. Young’s modulus, maximum load, and tensile strength were chosen as the most important mechanical parameters taken into account during the analysis. Two variants of cultivation, with the addition of ethanol . This synthetic substance is commonly applied in multiple experiments due to its structural specificity and high affinity for polysaccharides . It is kComparative analysis of bacterial nanocellulose membranes synthesized by the chosen strains was supplemented with tensile and compressive strength measurements. The assessment of the material’s susceptibility to plastic deformation determines its usefulness in various fields, including regenerative medicine, tissue engineering, textile, packaging, and paper industries. In this investigation, tension and compression tests were conducted to evaluate the intrinsic mechanical characteristics of the examined membranes, and at the same time, to confirm the previous observations that the cellulose derived from the 1st and 4th strains had a denser, more compact and, consequently, were less susceptible to plastic deformation structure. Herein, the measurements were performed on BNC films synthesized in 100 mL Erlenmeyer flasks filled with 80 mL of liquid SH medium. This bioreactor change resulted in obtaining thicker materials than those utilized in the strain screening stage. The outcomes of the measurements are presented in max values for compression tests did not reveal an analogous correlation and maintained at almost the same level of 1040 ± 5 N. Moreover, the results demonstrated that the denser cellulose films derived from the 1st and 4th strains had significantly a higher Young’s modulus, which directly indicates the material’s resistance to plastic deformation. The values for their breaking strength measurements were 3.1 GPa and 3.8 GPa for the 1st and 4th strains, respectively. In other words, the achieved Young’s moduli suggested a greater rigidity of these biological materials, and thus a better resistance to stretching. In addition, it can be observed that BNC films synthesized by the strain isolated from balsamic vinegar (12Et) were also characterized by relatively high values of the elasticity coefficient for tension tests (2.91 GPa). The stress–strain curves showed that bacterial nanocellulose membranes with looser structures  exhibited more inelastic behavior (Young’s modulus ~1.13  ± 0.15 GPa). Their reported relative elongation at breakpoint exceeded a value of 10%. The Young’s modulus observed under compressive load displayed the same tendency. As shown in K. hansenii ATCC 53582 (1) and K. xylinus E26 (4) produced BNC films that were highly resistant to compressive deformation. For instance, the elasticity coefficient reported for E26-derived cellulose was approximately 3.2 MPa. At the same time, the more gelatinous materials synthesized by the cultures numbered 6Et, 8Et, and 9Et  exhibited values of the Young’s modulus an order of magnitude lower under compressive load (320 ± 80 kPa), as compared to other analyzed samples. The mechanical performance studies revealed that BNC membranes produced by the 1st, 4th, and balsamic vinegar isolated (12Et) strains were characterized by the highest breaking strength . This outcome indicated a greater ability to withstand applied tensile stress without damaging the sample. Moreover, 12Et-derived cellulose membranes also exhibited the highest compressive strength, which reached a value of 806 ± 34 kPa. The conducted research revealed a strong positive correlation between the cellulose content and the mechanical properties of BNC. The denser and more compact fibril arrangement of bacterial nanocellulose membranes provides better strength characteristics, while the looser biomaterials with high water content were more susceptible to plastic deformation.Analyzing the results reveals that the bacterial cellulose membranes synthesized by the 1st and 4th strains were less prone to stress-induced deformation as compared to other tested materials. The maximum force required to result in their breakage was 213 N, which corresponded to an applied load approximately 35% greater than those used for BNC produced by the cultures numbered 6Et, 8Et, and 9Et. In contrast, the obtained FKomagataeibacter strains for the fabrication of bio-inspired composites, six previously selected microorganisms and their cultivation variants (see K. hansenii H3 (6Et), K. rhaeticus K4 (8Et), and the one isolated from balsamic vinegar (12Et). The BNC membranes synthesized by chosen microorganisms are presented in In order to choose the most appropriate ants see  were assComposites based on microbial cellulose belong to a new generation of biological materials, which can be widely used for both industrial and medical purposes. They consist of a three-dimensional BNC matrix acting as a scaffold and reinforcing compounds that give it specific physico-chemical and biological properties. The introduction of specific functional groups to chemically inert cellulose allows for the creation of composites with desired physical, chemical, and mechanical features which determine the application potential of this biological material. Herein, bacterial cellulose was modified at the stage of its biosynthesis (in situ method) by supplementing the growth medium with various concentrations of additives, such as citrus pectin (CP), apple pectin (AP), wheat starch (WS), polyvinyl alcohol (PVA), and polyethylene glycol (PEG). The addition of these polymeric compounds was intended to utilize their specific individual characteristics to improve or impart new functional properties to this biological material. This one-step strategy allows the added compounds to become part of the growing bacterial cellulose fibril network, resulting in stable bio-inspired composites . The obtCharacterization of the composite materials began with determination of dry mass content by a standard gravimetric method. The obtained physical parameters for bacterial cellulose modified with polymer nanoparticles were analyzed and compared to their native counterparts, as a control. The final outcomes of the measurements are shown in K. rhaeticus K4 (8Et) reinforced with citrus pectin reached WRC values of 11.3%, 12.5%, and 14.5% for 0.1%, 0.5%, and 1.0% of this plant heteropolysaccharide, respectively. In addition, the water retention capacity of the modified BNC films was mostly higher than the native ones  and modified in situ with 5% polyethylene glycol was 66.7 ± 0.7% (see K. hansenii H3 (6Et) reached the following WAC values for successively increasing concentrations of polyvinyl alcohol: 18.5%, 24.3% and 32.6%. In addition, it can be noticed that the presence of PVA caused a statistically significant decrease in the water adsorption properties of the modified biomaterials, when compared with native BNC membranes. Similarly, in the case of other analyzed composites , supplementation of the standard culture medium with these polymeric compounds mostly resulted in a reduction of the WAC values.Another important feature of bacterial cellulose composites from an industrial and medical application perspective was their water adsorption properties. For instance, maintaining proper moisture content inside the packages and removing exudates from foodstuff are key aspects that must be fulfilled to prevent microbial contamination . The res0.7% see . In the w/v) apple pectin reached a CRC value of 14.4 mg/g, which was more than seven times higher than its native counterpart. This investigation demonstrated that BNC/CP and BNC/AP membranes were able to adsorb significant quantities of Congo Red particles from aqueous solution during a one hour contact time, which makes them the most effective dye-removing composite materials among those analyzed . Thus, the barrier properties of these composites were reduced by 4% as compared to unmodified bacterial nanocellulose films. Such outcomes may be related to the hydrophilic nature of polyethylene glycol molecules. The greater number of hydroxyl groups present in BNC/PEG films allowed more water molecules to enter the bacterial cellulose structure [The barrier properties of bio-based packaging materials, such as the water vapor transmission rate (WVTR), play a crucial role in maintaining quality, microbiological safety and proper shelf life of food products . Controltructure . Moreovetructure .−1 and 1800–650 cm−1, are visible in all analyzed materials. Nevertheless, the modification of bacterial cellulose with various polymeric compounds affected the position, width, shape, and intensity of these typical IR signals, as well as led to the appearance of new peaks corresponding to the added functional groups.The chemical composition of native and modified bacterial cellulose samples, including their specific structural and conformational differences, was determined by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. This analytical method was used to gather information about the functional groups and chemical bonds present in the tested materials, and consequently to confirm the effectiveness of BNC functionalization. The collected IR spectra are shown in −1, which was attributed to O–H stretching vibration of cellulose I [−1 represents the strength of the intramolecular 3(O)H⋯O(5) hydrogen bond [−1 is related to C–H asymmetric stretching of aliphatic CH2 and CH3 groups [−1 and corresponds to the bending vibration of water molecules (H–O–H) absorbed in the biopolymer structure [−1 and 1315 cm−1 are attributed to CH2 symmetric stretching and out-of-plane wagging of the CH2 groups, respectively [−1 is attributed to the highly ordered  regions in bacterial nanocellulose [−1), which correspond to C–O–C antisymmetric bridge stretching of β-1,4-glycosidic bond, C–C, and C–O stretching vibrations, C–O–H bending of carbohydrates, and C–O–C pyranose ring skeletal vibration [−1, known as the “amorphous band” is related to the out-of-phase ring stretching of β-1,4-glycosidic linkages in bacterial cellulose [The ATR-FTIR spectra of BNC membranes contained a strong absorption band in the range of 3500-3200 cmlulose I . The nargen bond . On the 3 groups . Anothertructure . Two chaectively . Accordiellulose . The ATRibration . The narellulose .−1, attributed to O–H stretching vibrations in polysaccharides, became much broader. This width difference can be related to the interlinkage of pectin and BNC fibers through H bonding, which is in agreement with the literature data [–) found in the range of 1630–1600 cm−1 [−1), which was dominated by the stretching vibrations of C–O, C–C, and ring structures characteristic of pectin [−1. This band was associated with C–O bending deformation [−1 was broadened and slightly shifted towards lower wavenumbers, which proved that the formation of intermolecular hydrogen bonds between the hydroxyl groups of bacterial cellulose and polyvinyl alcohol occurred. The success of BNC modification was also confirmed by the appearance of a peak at around 1700 cm−1, assigned to carbonyl groups (C=O) present in the partially hydrolyzed acetate residues in PVA [−1. This IR signal was associated with CH2 deformation vibrations of vinyl polymers [−1 and 1650 cm−1 were significantly increased. This happened due to large amounts of hydroxyl groups in polyethylene glycol molecules [−1, characteristic of the aliphatic C–H stretching vibration, was also intensified. Likewise, the IR signal intensity in the region of lower wavenumbers was greatly enhanced. These outcomes were consistent with the data reported in the literature [Compared to native BNC, the ATR-FTIR spectra of the analyzed BNC composites revealed some changes in signal intensity, peak shifts, and the appearance of new absorption bands typical for the added reinforcing compounds. In the case of pectin-modified bacterial cellulose membranes, the peak at 3346 cmure data . As show600 cm−1 . Moreovef pectin . Anotherormation . The dess in PVA . Moreovepolymers . Similarolecules . The peaterature . All theThe ultrafine nanofibrillar network and well-ordered structure of bacterial cellulose ensure its relatively good mechanical properties. Moreover, it is possible to improve or modify the tensile and compressive strength of this biomaterial by supplementing the growth medium with reinforcing additives and alternative energy sources, such as organic acids, vitamins, and alcohols ,13. Hencmax) that BNC films can withstand during stretching is one of the most important parameters examined, clearly displaying the mechanical strength differences between the analyzed samples. Based on the results summarized in Mechanical characterization of the obtained biocomposites began with the examination of their stretching behavior. All the collected data from breaking strength measurements are presented in the S) values were 818 ± 54 N and 748 ± 55 N, respectively, at the highest additive concentration (5.0%). On the other hand, BNC films synthesized in the culture medium modified with wheat starch were the most susceptible to plastic deformation caused by compression forces. The evidence explicitly supporting this observation was 8Et-derived bacterial nanocellulose reinforced with 0.1% WS, which achieved a compression strength value almost 24 times lower than its native counterpart. Such results may be related to the fact that the addition of gelatinized starch changes the viscosity of SH medium, which in turn reduces the motility of bacterial strains and negatively affects binding of cellulose molecules during BNC synthesis [The obtained composites based on bacterial cellulose were also subjected to compression testing. Young’s modulus, the maximum crushing force, and compressive strength were the most important mechanical parameters considered in this analysis. A complete summary of the data collected from the compression measurements is provided in Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria. The results of antibacterial activity of the analyzed biomaterials after 24 h of exposure are presented in the In this study, the agar disc diffusion method was used to investigate the potential bacteriostatic properties of the chosen BNC composites against two representatives of Gram-negative  without ethanol addition, which may suggest that this strain is very promising not only from a financial point of view, but also when looking at the membrane properties of this strain, which can be observed in further examinations.In the literature, one may find numerous outcomes characterizing various strains of cellulose producing bacteria. Each strain delivers cellulose films at variable yield and with different structural parameters . While tat 30 °C ,20,49,50at 30 °C . In thisKomagataeibacter strains and their cultivation variants (K. hansenii H3 (6Et), K. rhaeticus K4 (8Et), and the one isolated from balsamic vinegar (12Et)), were chosen for bio-inspired nanocomposites fabrication. The organoleptic observations of the selected BNC-producing microorganisms revealed that the cultures numbered 6Et and 8Et synthesized cellulose membranes with a looser and more gelatinous structure than the 12Et-derived ones (K. hansenii H3 (6Et) and K. rhaeticus K4 (8Et) strains are potentially good candidates for a wide range of applications, including wound dressings, carriers for controlled drug delivery, scaffolds for tissue engineering, active and intelligent food packagings, absorbing materials, environmental remediators, and high-performance electronic devices [Komagataeibacter sp. isolated from balsamic vinegar (12Et) could be applied successfully as scaffolds for cells cultivation, dental and medical implants, artificial skin, blood vessels, bone and cartilage substitutes, and highly resistant packaging, papers, and textiles [The selection of suitable strains for the production of both bacterial cellulose membranes and their composites is very important step affecting the final quality, morphology, properties of the obtained biomaterials and, consequently, their further application. In this study, based on the BNC biosynthetic efficiency, mechanical strength and physical features  of the synthesized films, three ved ones . This resenii H3 Et, K. rh devices ,55,56,57textiles ,58,59,60Komagataeibacter strains is characterized by different structural and morphological features, and thus, specific physico–chemical and mechanical properties. Taking into account the individual characteristics and limitations of BNC membranes, they can be concretely modified to obtain biocomposites for the desired applications. Combination of the natural attributes of this nanofibrillar polymer matrix as well as the physico-chemical, mechanical, and biological properties of reinforcing compounds allows for the improvement of its parameters or to create materials with novel useful features. In this study, bacterial cellulose was modified by supplementing the basal medium with various concentrations of citrus pectin (CP), apple pectin (AP), wheat starch (WS), polyvinyl alcohol (PVA), and polyethylene glycol (PEG). The ATR-FTIR analysis confirmed the successful incorporation of these polymeric compounds into the three-dimensional nanocellulose network. The collected spectra indicated the presence of hydroxyl, carbonyl, carboxyl, methoxy, and acetyl groups that modified the original properties of chemically inert BNC . All of the investigated microorganisms are listed in the Bacterial cellulose synthesis was performed by using 13 strains of 4 × 7H2O (2.5 g/L), Na2HPO4 (2.7 g/L), and citric acid (1.15 g/L), which was prepared in distilled water at pH 5.7 and autoclaved before use.Microorganisms were stored at −70 °C. The strains were cultured in standard SH medium (Schramm and Hestrin medium) composed of glucose (20 g/L), yeast extract (5.0 g/L), peptone (5.0 g/L), MgSOv/v) and incubated at 30 °C for 2 days. Standard cultures, depending on the following analyses, were performed in 100 mL and 500 mL Erlenmeyer flasks filled with either 80 or 100 mL of liquid SH medium, respectively. Each time the medium was inoculated with 5% (v/v) of 2 days pre-culture and incubated for 7 days at 30 °C. Then BNC membranes were then cleaned of residual medium and bacterial cells by rinsing the membranes with water until white, then placing in 1% NaOH followed by neutralization in 1% acetic acid and water until the pH was neutral. All the cultivations of each analyzed strain, designed for particular experiments, were prepared in triplicates.Bacteria were activated from stock by cultivation in SH medium, and then supplemented with 2% agar in petri dishes at 30 °C for 5 days. A single colony was then transferred to 5 mL of liquid SH medium with or without the addition of ethanol  was required for the formation of the three-dimensional gel network [Bacterial cellulose composites were prepared according to the in situ strategy by adding different concentrations of compounds to the culture medium at the beginning of the BNC production process. BNC/CP and BNC/AP were obtained by supplementing 100 mL of SH medium with 0.1 g, 0.5 g, or 1.0 g of citrus/apple pectin and 12.5 mM CaCl network . In ordev/v) ethanol was inoculated with 5% (v/v) of 2 days pre-culture. Bacterial cellulose composites were grown in stationary conditions at the temperature of 30 °C. After 7 days of incubation, the obtained membranes were thoroughly purified with tap water to remove the remaining medium and bacterial cells and then treated with 1% (w/v) NaOH and neutralized with 1% (v/v) acetic acid. Afterwards, the BNC composites were washed in distilled water until the pH was neutral. The purified biomaterials were sterilized by autoclaving at 121 °C and stored at 4 °C until further analysis.The modified SH medium supplemented with 1% .Bacterial cellulose membranes (native and composites) obtained after seven days of stationary cultivation were weighed in a wet state and then dried to constant mass using a vacuum gel dryer . This process was carried out for 2 h at a temperature of 80 °C. Subsequently, BNC membranes were reweighed on analytical balance and dry mass content was calculated from the following equation:Dry mass content was expressed as a percentage and represents the mean value of at least three replicates. The experiment was conducted for both native BNC membranes and their composites.Water retention capacity is a parameter that describes a material’s ability to retain water and it is defined as the percentage of sample weight after centrifugation of the liquid to its initial value. The WRC of BNC membranes was determined according to the modified method described by Tomer et al. .Wet bacterial cellulose films  were cut into pieces with masses in the range of 0.3 to 0.4 g. Next, BNC samples were placed into Eppendorf tubes with specially prepared “gauze baskets” see  and centThis experiment was conducted in at least six replicates for each type of BNC samples.Determination of adsorption abilities was carried out for bacterial cellulose films that had previously been subjected to compression tests. The aim of this process was to compare the swelling properties of native BNC membranes synthesized by different strains as well as their composites. Cellulose samples squeezed out of the water were weighed and subsequently immersed in distilled water. The experiment was performed under stationary conditions at room temperature. After 20 h of rehydration, the change in the BNC membranes’ weight was determined on analytical balance. Water adsorption capacity was established by the following equation:The WRC average values and standard deviations were calculated from at least 3 replicates.The water vapor transmission rate (WVTR) of the composite materials was determined gravimetrically in accordance with the ASTM E96 standard (water method) . Brieflyy = 0.0413x) and the following equation:0 is the initial concentration of CR  were cut into fragments weighing 0.3–0.4 g and placed into 5 mL of 0.004% Congo Red (CR) solution (40 mg/L). The concentration of the dye used in these CR loading experiments was selected on the basis of the preliminary tests performed in the concentration range of 20–50 mg/L. The prepared samples were then shaken for 1 h at 100 rpm and 25 °C. Afterwards, the absorbance of the remaining dye solution was measured by UV/Vis spectrophotometer  at 497 nm. The Congo Red concentration adsorbed by wet bacterial cellulose was calculated using a standard dye calibration curve (bound) was calculated using a standard dye calibration curve (y = 0.0413x) from the following equation:adsorbed is the dye concentration adsorbed by BNC membrane after 1 h of soaking and C2 refers to the Congo Red concentration desorbed from BNC membrane  after the previously described adsorption experiment were gently placed in 5 mL of distilled water in order to rinse the dye from the samples. The process was carried out for 24 h in a shaker (Infors HT Minitron) at 150 rpm and 25 °C. After this time, the absorbance of the supernatant was measured spectrophotometrically at 497 nm. The amount of dye bound to bacterial nanocellulose membranes .Ultimately, Congo Red adsorption capacity (CRC) was established by the following equation:−1 and a resolution of 4 cm−1. The OMNIC Specta software program  was used for data analysis.FTIR was used to determine the functional groups and chemical bonds present in the composites, thus assessing the effectiveness of BNC modification. Bacterial cellulose membranes were cut into 2 × 2 cm squares and freeze-dried  prior to the analysis. The FTIR measurements were performed on a Nicolet 6700 spectrophotometer  equipped with an attenuated total reflectance (ATR) attachment under ambient conditions. The spectra of BNC, BNC/CP, BNC/AP, BNC/WS, BNC/PVA, and BNC/PEG were recorded in transmission mode within the range from 4000 to 650 cmmax), stress (σ), and elongation at break (ε), were determined by the TestXpert II software program . Stress was equal to the loading force, expressed in Newtons (N), divided by the cross-sectional area, measured as the width × thickness of the sample (m2). The strain was calculated as ΔL/Lo × 100%, where Lo is the initial length and ΔL represents the change in original length after breakage. The Young’s modulus values were determined on the basis of the linear stress/strain relationship. After the mechanical test, the compressive and breaking strength of native BNC and their composites were calculated from the following equation:Bacterial cellulose membranes (native and composites) were examined for tensile and compressive strength using a universal testing machine . The mechanical parameters characteristics for BNC, i.e., Young modulus, maximum force  and cut into 2.0 cm wide strips. The experiment was carried out with parameters adjusted to 25 mm/min−1 and a minimum distance between the clamps of 2 mm.Wet BNC membranes, after seven-days-long stationary cultivation and purification, were cut into 2.5 × 2.5 cm squares and tested for compressive strength. The Zwick Roell testing machine was set at a compression speed of 25 mm/minEscherichia coli) and Gram-positive (Bacillus subtilis) bacteria using the agar disc diffusion method (Kirby–Bauer test). These representative strains were activated in 15 g/L of commercially available enriched broth  and then incubated at 37 °C until an optical density at 600 nm (OD600) of 0.2 ± 0.02 ODU was reached. After the overnight cultivation of E. coli and B. subtilis, 0.01% of the bacterial suspension (~1.6 × 108 CFU/mL) was transferred to sterile LB medium containing 1.5% agar  and poured into the sterile Petri dishes. Meanwhile, the BNC-based composites in the wet state were cut into discs with a diameter 1 cm and sterilized at 121 °C for 15 min. Next, the samples were placed on top of previously poured Petri dishes with target bacterial suspensions, and subsequently incubated for 24 h at 37 °C. The bacteriostatic activity of the modified BNC membranes was monitored by observing inhibition zone formed around the discs. The experiment was performed in triplicate.The antibacterial activity of the BNC-based composites was examined against both Gram-negative (p ≤ 0.05). The assumptions of data normality and the homogeneity of variances were verified by Shapiro–Wilk and Bartlett tests, respectively.Experimental data were expressed as mean ± standard deviation of at least three measurements and statistically processed using RStudio software (version 1.4.1106). To detect significant differences between bacterial nanocellulose synthesized in SH medium with and without ethanol, Student’s t tests were conducted. Statistical analyzes for multiple comparisons were performed using one-way analysis of variance (ANOVA), followed by the post hoc Tukey’s HSD procedure. In all experiments, the differences between groups were considered significant at a probability level of 0.05 , K. rhaeticus K4 (8Et), and Komagataeibacter sp., isolated from balsamic vinegar (12Et)), were selected as the most suitable producers for the further fabrication of bio-inspired nanocomposites. Bacterial cellulose was modified at the stage of its biosynthesis by supplementing the growth medium with five representative additives, such as citrus pectin (CP), apple pectin (AP), wheat starch (WS), polyvinyl alcohol (PVA), and polyethylene glycol (PEG). The selected polymeric compounds significantly changed the physico-chemical and mechanical properties of chemically inert cellulose, especially the dye loading (adsorption) abilities , tensile and compression strength , and water adsorption/retention capacities (BNC/PEG). Thus, the resulting modified biological materials can be potentially useful in various fields of industry and medicine and may become a valuable and profitable competitor against commercial materials currently available on the market.Bacterial cellulose produced by different strains of the


DDA were observed in 56/121 individuals (46%), in 309/3388 teeth (9%). Hypomineralization or hypoplasia of enamel appeared in 21 (17%) patients. Altered root development appeared in 26 patients and hypodontia affected 13 (10%). Dental anomalies were observed in 36 (43%) individuals who received chemotherapy and not radiation, in 20 (52%) who received radiotherapy, and in 15 (60%) of those who received head and neck radiotherapy. Among patients who received only chemotherapy, young age (6 years or younger) was associated with a higher number of malformed teeth. In conclusion, antineoplastic treatment that combines chemotherapy and radiotherapy appears to increase the risk of DDA. Radiation to the head and neck area was shown to particularly increase the risk of DDA. No specific chemotherapy agent was found to be associated more than the others with DDA.Survival following childhood cancer has increased considerably. In an observational cross-sectional study, we assessed the prevalence of dental developmental anomalies (DDA) among childhood cancer survivors according to types of anticancer treatment. Permanent teeth were examined clinically and radiographically in 121 adolescents with a history of childhood malignancies, to identify DDA, namely hypomineralization or hypoplasia, microdontia, root changes and hypodontia Some complications of childhood cancer only become apparent later in life4. Long-term systemic complications can affect children's general growth and development, and impair their reproductive, respiratory, cardiovascular, skeletal, nervous and endocrine systems6.Current multimodality therapies have improved the survival of patients with childhood cancer. Consequently, research nowadays focuses on the long-term quality of life of these survivors3. Amongst other side effects, acute oral effects may include mucositis, bleeding, taste alterations, secondary infections, salivary gland dysfunction, periodontal conditions, trismus, osteoradionecrosis and neurotoxicity12. Late oral phenomena include exacerbated dental caries, temporomandibular dysfunction, osteoradionecrosis, cranio-dental development, dental developmental anomalies (DDA) and oral graft versus host disease12. Children are particularly vulnerable to the harmful effects of radiotherapy and chemotherapy. A new field in oncology, 'survivorship care', focuses on the identification, treatment and prevention of long-term side effects.Some oral manifestations may present shortly after inception of cytotoxic and radiation treatment, and some may only become apparent years or even decades after treatment11. Aberrations in initiation and proliferation of the teeth typically result in failure of tooth development, while insults during histodifferentiation lead to abnormal structure of enamel and dentin. Disturbances during morphodifferentiation can cause abnormal shape and size of teeth9. The continuation of severe or long-term upsets may damage root formation, thus leading to a shortened or tapered root. Root development plays a dominant role in the eruption; disturbance to a tooth root might impair tooth eruption and occlusion9.Morphogenesis and calcification of teeth begin in utero and continue for 14–15 years; the process is ongoing and complex. Permanent incisors and first permanent molars begin to mineralize around the time of birth but mineralization of permanent dentition is often completed only years later9. Reported abnormalities include hypodontia (missing teeth), microdontia , damage to root development , hypoplasia and hypomineralization , over-retention of primary teeth, impaction, premature eruption, malocclusion, decreased temporomandibular joint mobility, trismus and facial deformities20.First signs of dental disturbances can be expected within one or two years of anticancer treatment.While the literature describes late dental side effects in adults who underwent anticancer treatment during childhood, the effects of particular treatments on dental defects have not been described. Therefore, the purpose of this study was to examine and distinguish dental defects according to type of anticancer treatment , type of chemotherapy treatment, disease type and age during treatment. This information could help identify the children treated for cancer who are at the greatest risk for future dental problemsThis observational cross-sectional study was conducted and documented according to The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement. The data for this study were collected and the analyses performed during 2021.The study population consisted of individuals who underwent annual general examinations at the survivorship care clinic of Hadassah Hebrew-University Medical Center, Jerusalem, Israel during 2017–2019, including full oro-dental examinations at the Department of Pediatric Dentistry. Eligibility criteria included anticancer treatment at age under 18 years at the Department of Pediatric Hematology–Oncology, Hadassah and at least 7 years old on the day of the dental examinations.The demographic data recorded included the age at diagnosis, the age at the dental examination and gender. The medical history accessed comprised primary diagnosis, other medical conditions, the type of therapy or therapies applied ), systemic late complications, the chemotherapy agents used, the dates of chemotherapy sessions and complications after chemotherapy. Chemotherapy medications were divided into eight groups, classified according to their mechanisms of action.22. A root change was defined as a change in root size or shape by visual judgment of the X-rays, when the size of a root was 50% or less of the size considered “normal”.Using a dental mirror and explorer, permanent teeth were examined for dental caries and dental DDA under the artificial light of the dental unit. The radiographic dental examination included a set of two bitewings and a panoramic x-ray if indicated. The DMFT index scoring system was used to permit the calculation of caries. Decayed (D), Missing (M), Filled (F) per teeth (T) according to World Health Organization criteria. The presence of DDA was classified into five major groups: no disturbance identified, hypomineralization or hypoplasia, microdontia, root changes, and an absent tooth bud categorized as hypodontia. Hypomineralization or hypoplasia was defined as the developmental anomaly of enamel mineralization. We included every visualized opacity (demarcated or diffuse) that was deemed developmental according to the location and appearance. Microdontia was defined as a change in tooth size by visual judgment when the size of a tooth crown was 50% of the size considered “normal”19. Informed consent was obtained from the participants, or from the parents or legal guardians of those under age 18 years.The study protocol was approved by the Institutional Human Subjects Ethics Committee of Hadassah Medical Organization, Jerusalem, Israel . All the methods were carried out in accordance with relevant guidelines and regulationsp value less than 0.05 was considered statistically significant.The data were analyzed using statistical software . Descriptive statistics, including numbers and percentages of patients were tabulated for demographic and clinical characteristics. Chi-squared and Fisher's exact tests were utilized to examine associations between the categorical variables and treatment groups. The t-test was utilized to examine associations between the continuous variables (DMFT) and treatment groups. The data were stratified by age, and an analysis compared outcomes between participants aged ≤ 6 years and those aged > 6 and ≤ 12 years. For these analyses, a Of 131 childhood cancer survivors who were referred to the Department of Pediatric Dentistry for full oro-dental examinations, 121 met the study eligibility criteria. Their mean age was 7.1 years (range 0.1–17.7), and they underwent dental evaluations at a mean age of 15.9 (range 12.0–23.1) years. Table Table N = 46, 38%) had received a combination of three agents. The maximum combination treatment was composed of six agents. Ninety-eight patients had received alkylating agents. The number of malformed teeth and the types of malformation did not differ significantly according to chemotherapy agent. The mean DMFT in all 121 patients was 6.69 (standard deviation [SD] 6.19) , as was the total number of malformed teeth (p = 0.051). Statistically significant differences were not found in the mean DMFT according to chemotherapy agents (Table p = 0.037) and decayed teeth were more common among males (p = 0.025).Table h p = 0.01. StatisThe main finding of this study is that prevalences of dental anomalies in survivors of childhood cancer differed according to the type of cancer treatment administered. Prevalences were higher among those who had received radiotherapy, and particularly targeted to the head and neck area.29. Possible reasons for the discrepancy are the wide range of age of our cohort (0–18 years) and the range of cancer type and anticancer therapies. In addition, improved oncology treatments during recent years have become more targeted and confer fewer side effects, including dental side effects. Twenty-one patients (17%) in the current study displayed microdontia, in contrast to 0.8%-1.7%20 in healthy populations. Microdontia causes esthetic, functional and occlusal complications, which require professional dental treatment later in life. Alterations of tooth root were the most frequent malformation found in the current study; however, the rate of 21% was low compared to 86% and even 100% in other reports of cancer survivors20. In healthy populations, rates of 1.3%–5.6% have been reported20. As tooth development is a relatively slow process, DDA may become evident on radiographs only two years after a triggering event. Intensive, repetitive chemotherapy at the time of initial hard tissue formation may cause tooth hypodontia20, which is the most severe impairment in dental development. Hypodontia affects dental arches, and impairs tooth symmetry, esthetics and function. Hypodontia was seen in 11% of our patients, which compares with 2.8%–10% in healthy populations28.Treatment of childhood cancer is a success story of modern medicine, in which effective treatments have been identified for previously untreatable diseases. The growing population of child survivors of cancer, as well as young adult survivors, will require considerable attention from the medical and dental community in the decades to come. In our cohort of individuals who had received anticancer therapies, 46% had at least one malformed tooth; and 13% had more than five malformed teeth. Defects in enamel development and alterations in tooth size were equally distributed among the patients (17%). Sixty-two teeth of 21 (17%) patients displayed some form of hypomineralization or hypoplasia. This rate is lower than rates of dental alteration reported by other studies27. Acute damage from chemotherapy seems to be greater when the treatment is combined with head and neck irradiation or TBI, rather than administered as a monotherapy13. Notably, among our 15 patients who had received head or neck radiation (25–70 Gray), the prevalence of DDA was higher than among those who had received chemotherapy alone or TBI (12 Gray). This finding concurs with other studies14.Thirty-one percent of our patients who received chemotherapy were treated with radiation in addition. More than half the patients (53%) who received radiation displayed malformed teeth, a higher proportion than among those who received only chemotherapy (43%). This difference concurs with a previous study18, and the odontogenic toxicities induced by individual chemotherapy agents remain obscure29. The size of the current cohort was small for evaluating the effects of individual chemotherapeutic agents on dental developmental defects. We suggest that more studies will investigate associations with DDA, of chemotherapy agents according to their mechanisms of action, using the eight categories of chemotherapy agents presented herein.Many pediatric cancers are treated with a combination of multi-agent chemotherapy to create synergistic and additive effects. In the current study, 46 patients (38%) had received a combination of three chemotherapy agents; the maximum combination treatment comprised six agents. The use of multiple agents makes it difficult to attribute specific influence on odontogenesis to any single agent or therapyp = 0.001). Several publications suggested that children diagnosed with cancer between ages 3 and 5.5 years exhibited the most severe DDA29. This is consistent with the initial stage in this age interval, of root formation for all permanent teeth except the second and third molars. Treatment administered during the first 3.5 years of life was more likely to affect the dental lamina and crown formation, and to result in a small tooth22. Anticancer therapy administered after age 5 years may still disturb root growth, especially in late developing premolars and permanent second molars. However, by this age, the roots in the early developing teeth have already reached a moderate length, which improves the final result29. In several studies, the most extensive DDA  were reported in children who were treated before ages 5–6 years29, due to the proliferation of dental stem cells during this period29.Malformed teeth of all the types examined presented more frequently among children who received anticancer treatment at age 6 years or younger than among older children. Young age also remained a significant factor for the total number of malformed teeth among patients who received chemotherapy only (p = 0.037) and decayed teeth were more prevalent among males (p = 0.025).Only minor differences were found between boys and girls in the current study. Two significant differences regarding gender were noticed: microdontia was higher among females , particularly if combined with radiotherapy, and especially in the head or the neck region. No specific chemotherapy agent was found to be associated more than the others with dental side effects. The particular importance of our study in its cross-sectional examination of variables can be enhanced in large centers. This can help hone the results to identify risks of adverse dental effects for specific treatments and at particular stages of child development, and establish international guidelines for follow-up and treatment.


Hypotony maculopathy has been classically reported as a complication of glaucoma surgery or ocular trauma. There have been only a few reports of hypotony maculopathy following pars plana vitrectomy (PPV). Here, we report two cases of hypotony maculopathy occurring after PPV for epiretinal membrane (ERM) removal and characteristic photoreceptor folds observed on optical coherence tomography (OCT).A 53-year-old Korean woman (case 1) underwent phacoemulsification and posterior chamber lens implantation combined with 25-gauge PPV for ERM removal in the right eye. On the following day, she had severe ocular hypotony, with an intraocular pressure (IOP) that was unmeasurable using a pneumatic tonometer. Despite normalization of IOP, macular retinal and photoreceptor folds with photoreceptor disruptions developed, and Henle’s fiber layer hyperreflectivity was identified. Thereafter, retinal and photoreceptor folds gradually disappeared but photoreceptor disruption and Henle’s fiber layer hyperreflectivity did not improve until 1 year postoperatively, with persistent central visual field distortion and visual acuity worse than that at the preoperative state. A 20-year-old Korean man (case 2) underwent an additional 25-gauge PPV for ERM removal in the left eye. Examination on the following day showed ocular hypotony and retinal folds with peripheral choroidal detachment. Although IOP was normalized, further OCT revealed photoreceptor folds and photoreceptor disruptions. Since then, the photoreceptor folds resolved; however, the photoreceptor disruption remained in the macula at the 1-year follow up, with persistent distorted vision and visual acuity worse than that at the preoperative state.Early hypotony after vitrectomy for ERM could result in maculopathy leading to irreversible visual decline and metamorphopsia. Photoreceptor folds on OCT are characteristic features and the predominant mechanism of central visual loss in cases of hypotony maculopathy. Hypotony maculopathy, which was first described by Dellaporta in 1954 , is a coin situ keratomileusis for myopia in both eyes at 26 years of age and had no prior history of glaucoma, family history of ocular disease, or psychosocial history. Her best-corrected visual acuity (BCVA) was 20/30 in the right eye and 20/16 in the left eye, and the manifest refractive error was −2.00Ds −0.25Dc × 010A in the right eye and −1.25Ds −0.75Dc × 085A in the left eye. Anterior segment examination showed nuclear sclerosis in both eyes. Further dilated fundus examination and OCT revealed ERM with retinal thickening  of the right eye of unknown onset. She had undergone laser-assisted A 20-year-old Korean man presented with distorted vision (metamorphopsia) of the left eye. He underwent combined cataract surgery and PPV in the left eye for cataract and rhegmatogenous retinal detachment at the age of 18 years and had no prior history of glaucoma, family history of ocular disease, or psychosocial history. On examination, his BCVA was 20/16 in the right eye and 20/40 in the left eye, and the manifest refractive error was −8.25Ds −1.50Dc × 180A in the right eye and −8.25Ds −0.25Dc × 065A in the left eye. Dilated fundus examination and OCT revealed macular ERM in the left eye (Fig et al. [The treatment of hypotony maculopathy depends on the causes of hypotony and requires prompt management, as delayed normalization of IOP could give rise to permanent chorioretinal changes and result in poor visual outcomes , 8. Fortet al. , where tet al. , 11, 12.et al. [Visual acuity improved for the patient in case 1, whereas it did not recover for the patient in case 2, due to photoreceptor damage, despite normalization of IOP. The structural integrity of the macula and visual outcome are closely related; our cases share common features with those reported in a previous study by Ahn et al. , whereinet al. , photoreIn conclusion, we report two cases of hypotony maculopathy after PPV for ERM removal and the hallmark of macular photoreceptor folds on OCT. This report will help in understanding the mechanism of hypotony maculopathy following PPV for ERM removal and in preventing this vision-threatening complication.


Review of the literature cases revealed broadly consistent features except that topographical amnesia, olfactory hallucinations and emotionality have been reported rarely to date by other researchers. We conclude that transient epileptic amnesia is a distinctive syndrome of late-onset limbic epilepsy of unknown cause, typically occurring in late middle age. It is an important, treatable cause of memory loss in older people, often mistaken for dementia, cerebrovascular disease and functional amnesia. Its aetiology, the monthly occurrence of seizures in some patients and the mechanisms and interrelationships of the interictal features—amnestic and affective—all warrant further study.The term transient epileptic amnesia was coined in 1990 to describe a form of epilepsy causing predominantly amnestic seizures which could be confused with episodes of Transient Global Amnesia. Subsequent descriptions have highlighted its association with ‘atypical’ forms of memory disturbance including accelerated long-term forgetting, disproportionate autobiographical amnesia and topographical amnesia. However, this highly treatment-responsive condition remains under-recognized and undertreated. We describe the clinical and neuropsychological features in 65 consecutive cases of transient epileptic amnesia referred to our study, comparing these to our previous cohort of 50 patients and to those reported in 102 literature cases described since our 2008 review. Findings in our two cohorts are substantially consistent: The onset of transient epileptic amnesia occurs at an average age of 62 years, giving rise to amnestic episodes at a frequency of around 1/month, typically lasting 15–30 min and often occurring on waking. Amnesia is the only manifestation of epilepsy in 24% of patients; olfactory hallucinations occur in 43%, motor automatisms in 41%, brief unresponsiveness in 39%. The majority of patients describe at least one of the atypical forms of memory disturbance mentioned above; easily provoked tearfulness is a common accompanying feature. There is a male predominance (85:30). Epileptiform changes were present in 35% of cases, while suspected causative magnetic resonance imaging abnormalities were detected in only 5%. Seizures ceased with anticonvulsant treatment in 93% of cases. Some clinical features were detected more commonly in the second series than the first, probably as a result of heightened awareness. Neuropsychological testing and comparison to two age and IQ-matched control groups ( Transient epileptic amnesia is a distinctive syndrome of late-onset limbic epilepsy occurring in late middle age and is a treatable cause of memory loss in older people. Here, Baker et al. describe 65 cases, comparing these to their previous cohort of 50 patients and to 102 literature cases.  Initial misdiagnoses, in patients later shown to have TEA, have included TGA, psychogenic amnesia, transient ischaemic amnesia, incipient dementia and sleep inertia. The TEA-associated interictal memory deficits are also under-recognized: clinicians continue to reassure concerned patients that their memory is normal in the absence of tests of long-term retention or remote memory, which can reveal otherwise undetectable but relevant memory impairments.However, TEA remains a controversial disorder. Through our project website (The Impairment of Memory in Epilepsy (TIME Project) This paper has two primary aims. First, to consolidate the scientific description of TEA, we present a new series of 65 patients with TEA [The impairment of memory in epilepsy study: Phase 2 (‘TIME2’) case series] with whom to compare the core clinical features identified from our previous series of 50 patients [the impairment of memory in epilepsy study: Phase 1 (‘TIME1’) case series].Second, following the consolidation of all current evidence regarding the description of TEA, we propose a novel disease model, with discussion around key uncertainties about TEA, and important questions for future research.Cases of TEA were recruited to the TIME (The Impairment of Memory in Epilepsy) study, using Zeman et al.A history of recurrent witnessed episodes of transient amnesia;Cognitive functions other than memory are intact during typical episodes as observed by a reliable witness; andOther evidence for a diagnosis of epilepsy. This can be provided by any combination of:Epileptiform abnormalities in electroencephalogram (EEG),The concurrent onset of other clinical features of an epileptic seizure , or andA clear-cut response to antiepileptic drugs.n = 53), or self-referred (n = 12) after reviewing our project website (https://projects.exeter.ac.uk/time/). In this study, we include only participants referred to our study who were available for clinical assessment and—in most cases—neuropsychological assessment in the UK.Patients in TIME2 were either referred to the study via a consultant neurologist . All patients gave written, informed consent in accordance with the Declaration of Helsinki.We draw on two sets of control data. For standard neuropsychological measures, mood measures and for the assessment of autobiographical memory, data previously collected from the 24 healthy controls recruited in the TIME1 series were used again for comparison in TIME2. For measures of accelerated long-term forgetting, where some adjustment in administration procedures occurred between TIME1 and TIME2 , a new cohort of controls was recruited. This involved 22 age and IQ-matched healthy adults from the Exeter and Oxford areas.Interviews were conducted by a member of the study team. A detailed history was obtained from the patient and at least one witness. A standardized data-collection pro forma was used to collect information in relevant domains . Medical case notes and correspondence were reviewed.EEG and magnetic resonance imaging (MRI) reports were requested from the referring clinical teams.Participants were invited to complete a comprehensive neuropsychological assessment. This involved the same test battery as our original study, comprising measures of: general intelligence  subtest versionTo take account of methodological recommendations made elsewhereA list of 15 words  was presented orally over a maximum of 10 trials until at least 12 words (80% accuracy) could be recalled within a given learning trial. Upon reaching this criterion, participants were instructed to count backwards out aloud from 100 for 40 s, to prevent rehearsal of words. Recall of the words was assessed immediately following this distractor task, and at delays of 30 min and at 1 week (via telephone). After this last free recall trial, recognition memory was tested using the standard list of 30 words read aloud by the examiner (wherein the 15 targets are intermixed with 15 foils). The participant is asked to indicate for each word whether it had been in the original list or not. Scores were determined by the correct identification of words on the original list (leading to a maximum score of 15). Although participants were not forewarned about the delayed probes, participants were asked not to practice or write down the words between the face-to-face testing session and the telephone follow-up.Autobiographical memory was assessed using the modified autobiographical memory interview (MAMI), as in our previous study.Self-reported symptoms of depression or anxiety were measured through the hospital anxiety and depression scale.Statistical analysis of data obtained through neuropsychological testing was performed using IBM SPSS Statistics 25.0. Analyses of variance (ANOVA) were conducted to compare groups’ performances . Planned contrasts comparing: (i) TIME2 participants with controls and (ii) TIME1 participants with TIME2 participants were included. We applied a Bonferroni adjustment of alpha (0.05/11) = 0.0045 to correct for the number of neuropsychological measures compared in each instance.To examine any change in frequency of detected memory impairments across the two patient cohorts, a Pearson’s chi-squared test was used to compare the number of cases identified in each patient cohort (where cases of memory impairment were defined by performance 2 or more standard deviations (SDs) below the control mean on more than one neuropsychological test).To investigate long-term anterograde memory performance, word list recall scores were compared between TIME2 and a new, matched control group (see above) via a repeated-measures ANOVA, with factors of participant group (TIME2 or control) and delay interval . The Huynh–Feldt correction for nonsphericity was applied, where needed. Given the differences in procedure, no direct comparisons were made between the TIME1 and TIME2 data sets.Participants were entered into this analysis if they were not impaired on standard measures of memory, had satisfied the learning criterion  and demonstrated adequate retention over 30 min  and a within group factor of decade . For the one participant whose current decade and epilepsy onset were both in the 50s, data were not included in the analysis of the ‘50s’ decade, but appeared under ‘most recent’ decade, to reflect acquired after the onset of TEA. To examine autobiographical memory performance for events that occurred prior to the acute disturbances in memory due to epilepsy onset, only patients with an age of TEA onset >50 years were entered into this analysis. A separate comparison of recent memory  was also conducted.Lastly, self-reported symptoms of anxiety and depression were analysed using ANOVA to compare TIME1, TIME2 and healthy controls.We performed a literature search using the following keywords: ‘transient epileptic amnesia’ in MEDLINE, Embase and PsycINFO up to September 2018. Studies published prior to 2008 were excluded as these had been analysed in a previous review article.The data that support the findings of this study are not publicly available due to privacy and ethical restrictions.A total of 65 patients  were recruited between January 2008 and April 2016. Mean age at the onset of amnestic attacks was 61.4 years , and at entry into the study was 65.6 years .The grounds for the diagnosis of TEA in each case are summarized in TEA was the initial diagnosis in only 40% of cases (26/65). Other initial diagnoses were: temporal lobe epilepsy (18/65), TGA (10/65), transient cerebral ischemia/stroke (6/65) and ‘psychogenic’ (5/65). The median delay between first amnestic episode and diagnosis of TEA was 4 years .Median attack duration was 15–30 min, with a wide variation  of patients. In 33/65 (51%) brief unresponsiveness was reported in at least some attacks. 14/65 (22%) reported an epigastric aura. Olfactory hallucinations were described in 29/65 (45%); the same percentage reported motor automatisms, most commonly repetitive chewing or swallowing movements . Tonic–clonic seizures occurred in only 7/65 (11%) and were typically isolated or rare events.A total of 30/65 (46%) patients had dense ictal amnesia while the remaining 35/65 (54%) patients were able, on some occasions at least, to ‘remember not being able to remember’—i.e. had partial recall of their transient amnestic episodes. Repetitive questioning during episodes occurred in 41/65 (63%) cases.All patients were started on anticonvulsant medication, with 92% reporting complete cessation of attacks. The most commonly used final medications were lamotrigine  followed by levetiracetam , carbamazepine and sodium valproate (10/65 or 15% each). Topiramate was used in 3 patients  and zonisamide was used in one patient . Drug changes were required in 24 patients (37%), either due to inefficacy or side effects of the initial medication. This included changes from carbamazepine in 12 patients, lamotrigine in 9 patients, sodium valproate in 8 patients, levetiracetam in 4 patients and phenytoin in 2 patients. Final median daily doses were: lamotrigine 150 mg (range 50–300 mg), levetiracetam 1000 mg (500–3000 mg), carbamazepine 500 mg (300–1600 mg), sodium valproate 900 mg (400–2400 mg), topiramate 100 mg (50–150 mg) and zonisamide 400 mg (400 mg). At the time of interview, 59/65 patients (90.8%) were on antiepileptic monotherapy, the remainder taking two medications.A total of 57 patients (88%) reported AbA, ranging from patchy losses for the previous 1–2 years to loss of memories up to 30 years in to the past. These forgotten episodes were frequently noted in conversation with friends and family and typically included shared experiences such as weddings, holidays and birthdays.A total of 48 patients (74%) reported ALF, either without prompting or when asked if they had experienced memories fading more quickly that they would typically expect over hours to weeks.A total of 47 patients (72%) reported TopA.A total of 29 patients (45%) reported ictal olfactory hallucinations. A total of 16 (25%) reported a reduction in their sense of smell. Overall 34 patients (52%) reported olfactory symptoms of some kind.A total of 26 patients (40%) reported a state of emotional lability, principally involving a tendency for sadness/tearfulness to be provoked by relatively minor stimuli (24/26), and sometimes also a feeling of increased irritability (4/26).2 signal in the right hippocampus; (ii) frontal encephalomalacia secondary to previous brain injury, (iii) slight T2 signal change in both hippocampi and (iv) small cystic lesion in the right caudate with small area of gliosis right lateral ventricle and left posterior frontal lobe. A further two patients were noted to have evidence of vascular disease .Fifty-eight participants underwent a clinical MRI scan. Clear abnormalities were detected in 4 patients: (i) high Tn = 5) or a single sharp-slow complex (n = 2). These borderline abnormal findings were focused bilaterally (7/17), on the right (7/17) or on the left (3/17)  were epileptiform, 17/61 (28%) showed borderline abnormalities and 22/61 (36%) were normal. Epileptiform discharges localized to the temporal lobes, primarily, or solely, in the left hemisphere in 13/22, right-sided in 5/22 and bilateral in 4/22. Non-specific abnormalities most often involved theta activity, usually localized to the temporal lobes (11/17). Other non-specific abnormalities included a single sharp wave (t (3/17) .Age at seizure onset and sex ratio were consistent between the two series, resulting in a mean onset age of 62 years, and a male predominance .P = 0.003).Seizure duration and frequency were similar in the two series, with 12 brief attacks typically reported per year. Seizures on waking were reported more often in TIME2, with an increase from 74% to 94% of cases . Pure amnestic seizures and tonic–clonic seizures also occurred with similar frequency in the two series, in 24% and 8% of patients respectively. There was an increase in reports of brief episodes of unresponsiveness across the two cohorts, half the cases reporting this in TIME2 compared to a quarter of cases in TIME1.Partial recollection of attacks occurred in around half of the patients in both groups.Over 90% of patients in both series reported complete cessation of seizures following the initiation of medication.P < 0.05), with almost twice as many patients reporting accelerated forgetting (74%) and topographical amnesia (72% of cases) as in TIME1.These specific interictal memory disturbances were reported more often in TIME2 .Increased emotionality was also reported more often in TIME2 than it had been in TIME1 .Neuropsychological test results for patients in TIME1, TIME2 and control participants are shown in P < 0.0045).All three groups of participants demonstrated above average intellectual ability. There were no significant differences between TIME2 and healthy controls on language or executive function tasks, however, significant reductions were apparent on all of the anterograde memory tasks . All participants completed between 3 and 10 learning trials, with no differences between the TEA and control groups on the total number of learning trials , or average final trial score , suggesting an equivalent performance during the learning phase of the task.ALF testing was completed per protocol in 36 of the TIME2 participants . Thirteen were excluded from analysis due to impaired performance on standard tests of anterograde memory . A further 4 failed to meet the word list learning criterion, and an additional patient performed poorly at the 30-min interval. Nineteen TEA participants and 22 age and IQ-matched healthy controls were therefore included, subject to the same exclusions listed above , a significant main effect for the delay interval  = 153.73, P < 0.001), and, importantly, a significant group × delay interaction  = 6.29, P = 0.008). Planned contrasts to explore group differences across the time intervals, showed that, while the TEA and control participants did not differ significantly from each other in their change shown between 40-s and 30-min recall  = 0.03, P = 0.86), the degree of forgetting was greater in TEA participants compared to controls when comparing the words recalled at the short delay intervals  and performance at the 7-day interval  = 7.74, P = 0.008)  see .F = 8.12, P = 0.002, with contrasts confirming that this effect was only significant at the final level of delay (P = 0.003) and not at early intervals (P = 0.97)] but was no longer significant when comparing ALF− patients with healthy controls  = 0.40, P = 0.533, with a significant main effect for delay, but no main effect for group).Within the TEA group, 13 participants had reported symptoms of ALF. To explore whether the group × delay interaction was only evident within these participants, additional separate analyses were run comparing control performance firstly with TEA participants who did (ALF+) and did not (ALF−) self-report ALF. As predicted, the interaction remained significant for ALF+ patients versus healthy controls [Although it was not possible to compare recognition memory scores of TEA and control participants, as control data were not collected, 8 of the 19 patients with TEA performed at or below a score of 9, a level sometimes used to differentiate performance above chance. An additional participant refused the task after being unable to recall any words on free recall. Scores ranged from 7 to 14 out of 15 , with only 3 TEA participants scoring above 12.P = 0.662; 1-week retention and seizure frequency prior to anti-convulsants: rho = −0.10, P = 0.749). We note, however, that patients were seizure free at the time of testing.Finally, to check for any associations among seizure variables  and long-term retention, Spearman’s rho correlations were examined. There were no significant results .The MAMI was conducted with 24 TEA participants  from TIME2 who met the criterion of TEA onset from age 50 years onwards. As in TIME1, eligibility also required participants to show adequate performance  on standard anterograde memory tests . Individuals included did not differ on demographic , clinical  or non-memory neuropsychological measures  from those in TIME2 who were not tested on the MAMI. Those included reported slightly fewer symptoms of depression on the hospital anxiety and depression scale, but this did not signify a clinically meaningful difference as both groups were within the normal limits. TEA participants were age and IQ-matched with 18 healthy controls from TIME1  = 5.758, P = 0.002). This followed a quadratic function  = 10.92, P = 0.002) such that memories for 20s and 50s were better recalled than for the middle decades. A significant main effect was also found for group  = 20.98, P < 0.001), with average personal semantic recall for controls slightly higher, at 9.58 out of 10, as compared with 8.53 out of 10 for TEA participants. However, no decade x group interaction  = 2.65, P = 0.059) was observed, indicating that the pattern of performance of TEA participants, while lower, mirrored that of the controls. We note that the high mean score of controls on our measure of personal semantic memory raises the possibility of a ceiling effect, which could lead to some underestimation of the corresponding deficit among patientsF = 4.39, P = 0.006), again with contrast testing confirming a quadratic relationship where memories from the 20s and the 50s were better recalled that those from the middle periods  = 11.95, P = 0.001). The main effect for group was also significant  = 45.20, P < 0.001), with average episodic recall remaining high for controls at 9.14 out of 10, but dropping to an average score of 6.23 out of 10 for TEA participants. The decade x group effect was not significant  = 0.87, P = 0.457), indicating that the overall pattern of performance across the decades was similar for the two groups.Similar but more striking results were found in the episodic domain. A significant main effect arose for decade  up to 79% (for the 50s decade), with only two participants (13%) not classified as impaired on any of the examined decades. Thus, impairments were highly prevalent and observed across the lifespan.P = 0.624), but there was a significant, negative association between average episodic MAMI score and total number of attacks , indicating that those who had experienced more seizures showed poorer autobiographical memory.Finally, to check for any associations among seizure variables  with overall autobiographical memory performance, Spearman’s rho correlations were examined. There was no significant relationship between average episodic memory performance on the MAMI and frequency of seizures prior to anti-convulsant medication  = −1.538, P = 0.129) there was a statistical difference regarding reported symptoms of anxiety (t (65.338) = −2.219, P = 0.03). This numerical difference, however, is not clinically significant as both groups reported mean levels below the standard clinical cut-offs (<8).Participants reported relatively few symptoms of anxiety or depression see . While nP > 0.16) on standard neuropsychological tests except that the TIME2 group performed more poorly on the immediate recall of a short story (t (101) = −3.05, P = 0.003). At the individual level, a third of TIME2 participants (34%) showed significant memory impairment (>2 SDs below the control mean on 2 or more memory tests). Although a slightly higher number than observed in the TIME1 cohort (28%), the difference was not significant . No differences were observed in self-reported symptoms of anxiety (P = 0.159) and depression (P = 0.216). Thus the findings of standard neuropsychological tests and mood of TIME1 appeared largely replicated in this second cohort.Performance of TIME1 and TIME2 cohorts was similar  an anterograde memory impairment that—in some cases—became apparent only at longer than standard delays and (ii) an autobiographical memory impairment affecting memory for both semantic and episodic details, the latter more severely, both occurring in participants with normal memory performance on standard tests.Using the search term ‘Transient Epileptic Amnesia’, we identified 322 publications between 2008 and 2018, after deduplication . The res,,Summing across these studies, the sex ratio was equal , though three of the four larger series reported a male preponderance.The majority of reported episodes fall between a few minutes and 1 h, but there is extensive variation with seizure episodes lasting from <1 minA total of 13/23 (57%) studies included in this review describe episodes of TEA occurring on waking in 27/60 (45%) patients.The frequency of TEA attacks ranges from several times per weekPure amnestic seizures are described in between 17%Patients with TEA respond well to treatment with anti-epileptic medication. 94/96 cases (97.9%) in whom the response to anti-epileptic treatment was reported describe a reduction in the number of seizures following initiation of medication. In 59 of these patients, this is documented as being complete seizure cessation, and in 12, this reduction is described as partial (>50% reduction in seizures). Ramanan et al.The interictal features described in TEA have not been routinely assessed in either case studies or case series of TEA patients and are therefore not as thoroughly described. Findings in studies where these features have been investigated are described below.A total of 14/23 studies included in this review describe interictal autobiographical memory impairments. Mosbah et al.,A total of 10/23 studies describe the presence of ALF in TEA, in 25 patients. In studies with multiple patients, this feature was described in 16/30 (53%),TopA is described in only 2/23 studies (2 patients); described as either ‘a tendency to lose her way even in familiar locations’A decreased sense of smell, occurring in the setting of TEA was described in only 1 study (1 patient).Two of the 23 studies describe a clear change in the emotional character of their patients with TEA. In one case, this change was becoming angry and short-tempered,,,,,,The rate of EEG abnormalities reported in published case series has exceeded 50%  whether TEA should be regarded as an epilepsy syndrome, (ii) the neuropsychological and neurobiological bases of the prominent associated interictal memory disturbance and (iii) a model designed to capture current understanding of the condition and to identify key unanswered questions for future research.There are compelling grounds for concluding that epilepsy is the underlying cause of the disorder described here: our diagnostic criteria require the presence of one or more indicative features, specifically the detection of epileptiform change on EEG, the occurrence of other clinical phenomena suggestive of epilepsy, such as paroxysmal alteration of awareness or olfactory hallucinations, and/or a clear-cut response to anticonvulsant drugs. While opportunities to record EEG during an amnestic episode are exceptional, such recordings indicate that transient amnesia can occur both as an ictal and as an immediately postictal manifestation.If the diagnosis of epilepsy is accepted in these cases, do they belong to a distinctive epilepsy ‘syndrome’? Epilepsy syndromes involve a ‘complex of signs and symptoms that define a unique epilepsy condition’; the complex should involve ‘more than just the seizure type’ but is distinct from an ‘epilepsy disease’, a condition with a ‘single, specific, well-defined aetiology’.While our two consecutive series of patients with TEA display marked commonalities, in demographic features and ictal characteristics, they differ with respect to the reported frequency of episodes on waking, interictal memory disturbance and emotional lability. In each case, the frequency of these features was higher in TIME2 than in TIME1. While we attempted to gather clinical data in a consistent fashion over time, we suspect that the apparent increase in the frequency of these features reflects increased vigilance, stimulated by our initial findings, rather than any true difference between the patient groups. However, whether or not this is the case, these modest quantitative differences between the two series do not undermine the key elements of the syndrome, outlined above.The 115 patients described from our centre broadly resemble those reported from other centres in most respects, in particular, age of onset and seizure characteristics. The interictal neuropsychological features of TEA have been reported less frequently in other reports than in ours, but both AbA and ALF have been described repeatedly. Olfactory disturbance and emotional lability are much more common in our series than in other reports: Whether this reflects a true difference, or a difference in ascertainment, is unclear.Some cases in our current series are atypical with respect to age, length of amnesic episode, treatment resistance; one additional case reported provocation of amnesic episodes by exertion. Two cases  presented below the age of 30, more than three SDs below the mean age at presentation. Case 305 satisfied all three diagnostic criteria, with attacks of typical duration; case 340 satisfied one criterion (clear-cut treatment response) with longer than usual attacks (1–2 h); both had attacks on waking. Case 305 had experienced 26 episodes, case 340 five episodes. 4 patients  had ‘TGA-like’ episodes of amnesia lasting >2 h: Three of these patients satisfied two criteria each , while case 257 satisfied one criterion (treatment response). All four patients had experienced >10 episodes, and three of the four described episodes on awakening. All four were in their fifties. Five patients described an incomplete response to treatment . Three  satisfied three criteria, while case 356 satisfied two  and case 261 satisfied one (clear-cut but incomplete treatment response). All had experienced frequent events of typical duration (<1 h), some occurring on waking. Three patients were in their sixties, two in their fifties. One patient, an overseas patient assessed in the UK but not included in the current series, described episodes of typical duration, occurring at roughly monthly intervals, often on waking, and gave a clear description of precipitation of episodes by exertion, a feature more often associated with TGA; some episodes were accompanied by olfactory hallucinations and video-telemetry confirmed the diagnosis of epilepsy. Thus, these atypical features generally occurred singly, in patients whose characteristics were otherwise typical for TEA, with no suggestion of distinct subgroups or likely alternative diagnoses.,Finally, in some patients, the clinical phenotype falls in a grey zone between ‘typical’ temporal lobe or limbic epilepsy, and TEA. For example, patients with focal seizures with impaired awareness sometimes exhibit a period of prominent postictal amnesia. There is also a group of patients with temporal lobe epilepsy who present with notable interictal memory disturbance of the kind associated with TEA, accompanied by subtle seizures, but who never have amnestic events of the kind required for a diagnosis of TEA. The term ‘Epileptic Amnesic Syndrome’ has been proposed to accommodate patients with temporal lobe epilepsy (TLE) accompanied by such interictal memory disturbance regardless of whether they do or do not also have amnestic seizures.Thus, TEA is a distinctive epilepsy syndrome, with substantially consistent features across the two series of patients described from our centre and in recent reports from other centres. The relatively minor inconsistencies between our two series are likely to be explained by heightened awareness of the clinical features by the time we studied our second series. The existence of ‘atypical’ and ‘grey’ cases indicates that there are areas of overlap between TEA and other related epileptic conditions but does not invalidate the proposal that TEA is a distinctive epilepsy syndrome.,,,The majority of patients with TEA describe characteristic symptoms of interictal memory disturbance, in particular symptoms of ALF, AbA and TopA. These are often the most prominent and sometime the earliest symptoms of TEA.These phenomena are now established clinical entities with operational definitions. Some individuals with TEA—and other conditions—who perform within normal limits on standard measures of memory nevertheless have measurable evidence of ALF and/or AbA in the presence of corresponding symptoms. There is, however, continuing uncertainty about the pathophysiology of these phenomena, specifically regarding which phase of memory processing is perturbed see  and whet,,,,In the case of ALF, the presence of memory impairment at extended intervals in patients with apparently normal learning, and intact early recall, suggests an impairment of memory consolidation. This interpretation is supported by examples of patients with impeccable performance on anterograde tests at standard intervals who nonetheless show marked accelerated long-term forgetting.,,,,,,There is also uncertainty over the relative importance of reversible functional factors, particularly ictal or interictal discharges versus structural factors in the causation of ALF. Studies—predominantly in patients with TLE—identifying a positive correlation between seizure frequency and ALF,,,With respect to the AbA associated with TEA, detailed case studies indicate that TEA can erase or render inaccessible previously detailed autobiographical memories.,Anecdotal evidence points to a role for epileptic activity in the genesis of TEA-related AbA. This idea receives some support from the significant negative correlation, reported above, between total number of seizures and the episodic memory score in the current (TIME2) patient series. The probable though controversial association between electroconvulsive therapy, which produces iatrogenic seizures and AbA,,Cognitive deficits occurring in epilepsy are sometimes caused by drug treatment and by mood disturbance. However, given that both ALF and AbA can be detected in patients with TEA prior to treatmentIn summary, ALF and AbA, both common interictal features of TEA, reflect disorders of several stages of memory processing, affecting acquisition and consolidation in the case of ALF, storage and retrieval in the case of AbA for remote memories (with a contribution from ALF in the case of Aba for post-onset memories). Current evidence favours a predominant role for neurophysiological factors in causing these phenomena in TEA, though structural factors are undoubtedly relevant in other contexts, and may also play some role in TEA.The aim of this section is to summarize current knowledge of TEA, identify unanswered questions and propose testable hypotheses regarding the underling mechanisms .,The majority of cases of TEA are of unknown aetiology, but its typical occurrence in middle aged people, with a probable male predominance, points to an age-related susceptibility and the possible relevance of hormonal factors. Although TGA is unlikely to result from epilepsy in the majority of cases, the similarity in the ages of patients affected by TGA and TEA suggests that common age-related factors underlie both conditions. Rare symptomatic  cases of TEA are described and discussed further below. We have recently reported a case of TEA occurring secondary to NMDAR antibody mediated encephalitis.,Manual and automated measurement of brain structures in TEA has revealed mild atrophy of limbic regions, namely bilateral straight gyrus, medial orbital gyrus, hippocampus and right perirhinal cortex.,The amnesic episodes in TEA, which typically last around half an hour, are unusually prolonged for epileptic seizures: We discuss their mechanism further below. Their occurrence on waking is in keeping with a medial temporal seizure source.Surface EEG recording during an amnesic attack was performed in nine literature cases and one TIME1 case.We noted a characteristic form of emotional lability in 18% of our first series of patients, and in 40% of the current series, a result, we suspect, of greater awareness of this feature. This typically involves a heightened emotional reactivity to poignant but relatively minor triggers, such as a story or tune on radio or TV, or a social encounter, often leading to unexpected tearfulness. A strikingly similar phenomenon has been described recently among patients with limbic encephalitis.,,In the case of AbA, structural pathology (‘1’) in the medial temporal lobe, perhaps detectable using high field MRI imaging,The growing world literature on TEA included 94 cases at the time of our previous review in 2008, among them 50 from our first series; in the current paper we report a further 65 patients studied at our centre and 114 cases from elsewhere reported since 2008. This now substantial patient cohort indicates that TEA is a distinctive form of late-onset limbic epilepsy. It gives rise to recurrent episodes of transient amnesia, typically lasting for around 30 min, often on waking, frequently occurring at intervals of around one month. The predominantly ‘memory-related’ presentation of TEA often leads to referral to memory clinics or for psychiatric assessment; diagnosis is frequently mistaken or delayed. Olfactory hallucinations are a common accompaniment and useful diagnostic clue. There is, in several series, an unexplained male predominance. Interictal memory impairment, specifically ALF and AbA occur in the majority of patients, sometimes associated with a distinctive form of emotional lability. The condition is most often of unknown aetiology, and such cases have a benign prognosis. TEA occasionally occurs as a result of structural pathology and as a manifestation of auto-immune epilepsy. The aetiology of most cases of the condition, the monthly occurrence of seizures in some patients and the mechanisms and interrelationships of the interictal features—amnestic and affective—all warrant further study. The current report establishes TEA as an important, treatable cause of memory loss in older people, often mistaken for dementia, cerebrovascular disease and functional amnesia.Brain Communications online.John Baker received funding from the Alzheimer’s Society .Christopher Butler received funding from the Medical Research Council (Clinician Scientist Fellowship MR/K010395/1).Adam Zeman received funding from the Dunhill Medical Trust (grant number R322/1113).The authors report no conflicts of interest.fcab038_Supplementary_DataClick here for additional data file.