Multiple signal amplification strategies for ultrasensitive label-free electrochemical immunoassay for carbohydrate antigen 24-2 based on redox hydrogel.
In this work, multiple signal amplification strategies for ultrasensitive label-free electrochemical immunoassay for carbohydrate antigen 24-2 (CA242) were developed using redox sodium alginate-Pb2+-graphene oxide (SA-Pb2+-GO) hydrogel. The SA-Pb2+-GO hydrogel was synthesised by simply mixing SA, GO, and Pb2+ and then implemented as a novel redox species with a strong current signal at -0.46V (vs. Ag/AgCl). After the three-dimensional and porous SA-Pb2+-GO hydrogel was in situ generated on a glassy carbon electrode (GCE), chitosan was adsorbed on the obtained electrode to further enrich Pb2+. When chitosan-Pb2+/SA-Pb2+-GO/GCE was incubated with anti-CA242 using glutaraldehyde and blocked by bovine serum albumin, the immunoassay platform for CA242 was obtained. Owing to the addition of GO, the obtained conductive SA-GO/GCE was beneficial for signal amplification. After incubating SA-GO/GCE with excessive amounts of Pb2+, the resistance of SA-Pb2+-GO/GCE further decreased and a strong redox signal was obtained. The chitosan fixed by electrostatic adsorption resulted in further adsorption of Pb2+, behaving as further amplifying the signal and improving conductivity. In this case, multiple signal amplification strategies were involved in the proposed immunosensor for the ultrasensitive detection of CA242. Under the optimal conditions, the proposed immunosensor exhibited a wide linear range from 0.005UmL-1 to 500UmL-1 with an ultralow detection limit of 0.067mUmL-1. In comparison to previous works, the sensitivity of this method was 32.98μA (log10CCA242)-1, which was a five-fold increase from the previous works.
['Tang|Zhongxue|Z|', 'Fu|Yuanyuan|Y|', 'Ma|Zhanfang|Z|']
D000464:Alginates D055910:Antibodies, Immobilized D015295:Antigens, Tumor-Associated, Carbohydrate D015374:Biosensing Techniques D048271:Chitosan D055664:Electrochemical Techniques D020723:Glucuronic Acid D006108:Graphite D006603:Hexuronic Acids D006801:Humans D020136:Hydrogel, Polyethylene Glycol Dimethacrylate D007118:Immunoassay D007854:Lead D057230:Limit of Detection D010084:Oxidation-Reduction D010087:Oxides
Electrochemical immunoassay Carbohydrate antigen 24-2 Hydrogel Chitosan Sodium alginate Sodium alginate-Pb(2+)-graphene oxide