Dual-aptamer-based voltammetric biosensor for the Mycobacterium tuberculosis antigen MPT64 by using a gold electrode modified with a peroxidase loaded composite consisting of gold nanoparticles and a Zr(IV)/terephthalate metal-organic framework.
An ultrasensitive aptasensor is described for the voltammetric determination of the Mycobacterium tuberculosis antigen MPT64 in human serum. Firstly, an amino-modified Zr(IV) based metal-organic framework (MOF; type UiO-66-NH2; made up from Zr6O32 units and 2-amino-terephthalate linkers) with a high specific surface was synthesized and used as the carrier of the gold nanoparticles and the aptamers. Then the signalling nanoprobe was fabricated after the horseradish peroxidase was cast on the nanomaterials. The two aptamers with synergistic effect on binding MPT64 were anchored on the gold electrode. Differential pulse voltammetry indicated that the peak current is highest if the ratio of the two aptamers is 1:1. The assay has a wide linear response range (0.02 to 1000 pg·mL-1 of MPT64) and a 10 fg·mL-1 detection limit at a working potential of around -96 mV (vs Ag/AgCl). The results show this biosensor to be a viable tool for detection of tuberculosis at an early stage. Graphical abstract Schematic presentation of the construction of the nanoprobe and biosensor. Firstly, the surface of UiO-66-NH2 was anchored to gold nanoparticles (AuNPs). A dual-aptamer and HRP were added to form the signalling nanoprobe (Aptamer/HRP/AuNPs/UiO-66-NH2). Then, the aptamers I and II were attached on the surface of gold electrode and 6-mercapto-1-hexanol was used to block the uncovered active site of the gold electrode. Finally, after incubation with MPT64, the signalling nanoprobe was dropped on the modified electrode and the DPV measurements was used for the analysis of Mycobacterium tuberculosis antigen MPT64. (PVP: poly(vinyl pyrrolidone); HRP: horseradish peroxidase; MCH: 6-Mercapto-1-hexanol; HQ: hydroquinone; BQ: benzoquinone).
['Li|Ningning|N|', 'Huang|Xing|X|', 'Sun|Duanping|D|', 'Yu|Weiye|W|', 'Tan|Weiguo|W|', 'Luo|Zhaofan|Z|', 'Chen|Zuanguang|Z|']
D000942:Antigens, Bacterial D052157:Aptamers, Nucleotide D001426:Bacterial Proteins D001483:Base Sequence D015374:Biosensing Techniques D004563:Electrochemistry D004566:Electrodes D006046:Gold D006801:Humans D057230:Limit of Detection D053768:Metal Nanoparticles D000073396:Metal-Organic Frameworks D009195:Peroxidase D010795:Phthalic Acids D015040:Zirconium
Mycobacterium tuberculosis MPT64 Metal-organic framework UiO-66-NH2 Horseradish peroxidase Electrochemical aptasensor