ABSTRACT
Objective Todesign a novel impedimetric immunosensor basedon AgI mimic enzyme nanomaterial for detecting carcinoembryonic antigen (CEA) in serum with high sensitivity. Methods A novil chitosan modified AgI (CS-AgI) nanomaterial was synthesized and was characterized by transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR). Then by utilizing CS-AgI labeled CEA antibody as tags, we prepared a novel impedimetric immunosensor on the gold electrode using the sandwich-type immunoassay. The electrochemical propertiesof the prepared impedimetric immunosensor were observed by electrochemical workstation and the concentration of CEA in sample was quantitatively analyzed. Results The synthesized CS-AgI nanoparticles were spherical in shape, with the particle size being 100 nm; the particles were employed to construct immunosensor as signal markers. The immunosensor had an excellent electrochemical performance in detection of CEA under PBS base solution of pH = 7, and its AC impedance response increased with the increase of the logarithm of CEA concentration, exhibiting a good linear relationship in the range of 0. 1ng/mL to 80ng/mL (r = 0.996), with a detection limkof 0. 05 ng/mL. Conclusion Based on AgI mimic enzyme nanomaterial, the impedance immunosensor prepared in this study shows a high sensitivity in detecting CEA; meanwhile, t has acceptable selectivity, repeatability and stability, providing an experimental evidence for early diagnosis and treatment of cancer.
ABSTRACT
Objective To study the catalytic capability of glucosamirie-Cu( Ⅱ) complex for decomposition of H2O2 and its relative factors. Methods Glucosamine-Cu( Ⅱ ) complex was prepared by the reaction of D-glucosamine hydrochloride with Cu2+ in aqueous solution, then added it into H2O2 solution. The concentration of H2O2 was determined by titrimetric analysis in a regular interval of time, the rate of decomposition of H2O2 was obtained in various conditions. Results Strong catalytic capability of glucosamine-Cu( Ⅱ ) complex was obtained at 30℃ pH 6. 5, the rate of decomposition was over 90% after 12h, and was almost 100% after 24h. Conclusion The complex of glucosamine-Cu( Ⅱ ) showed good catalytic capability for decomposition of H2O2.