Selective sensing of cysteine on manganese dioxide nanowires and chitosan modified glassy carbon electrodes.
We report a simple approach for the selectively electrochemical sensing of cysteine (CySH) using beta-MnO(2) nanowires modified glassy carbon (GC) electrode via a direct and facile electrochemical co-deposition process with chitosan hydrogel. The electrode showed excellent electrocatalytic effect toward cysteine oxidation. A possible reaction mechanism related to the formation of surface complexes was proposed: the -SH group is the reacting group in the reaction between cysteine and MnO(2), while the -NH(2) group acts as an anchor to stabilize the surface complexes. The electrocatalytic behavior is further developed as a sensitive detection scheme for cysteine by amperometric measurement, which shows a large determination range of 0.5-630 microM and a low detection limit of 70 nM. Other nineteen amino acids in a 20-fold concentration do not interfere in the detection of cysteine. Furthermore, other biological species containing -SH group or S-S bonds, such as glutathione, cystine, and bovine serum albumin (BSA), show no interferences because of steric hindrance and inactive S-S bonds.
Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
Yu-Hui
YH
Bai
Jing-Juan
JJ
Xu
Hong-Yuan
HY
Chen
D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002244:Carbon; D048271:Chitosan; D003545:Cysteine / Q000032:analysis* / Q000737:chemistry; D055664:Electrochemical Techniques; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D017895:Manganese Compounds; D046529:Microscopy, Electron, Transmission; D053770:Nanowires; D010084:Oxidation-Reduction; D010087:Oxides; D013055:Spectrophotometry, Infrared; D014961:X-Ray Diffraction
D017895:Manganese Compounds; D010087:Oxides; D002244:Carbon; D048271:Chitosan; D003545:Cysteine; C016552:manganese dioxide