Zwitterionic poly(carboxybetaine) functionalized conducting polymer polyaniline nanowires for the electrochemical detection of carcinoembryonic antigen in undiluted blood serum.

Biocompatible materials, such as zwitterionic poly(carboxybetaine methacrylate) (polyCBMA), are of extraordinary importance in growth of bioelectronics and biosensors, because they not only greatly suppress nonspecific protein adsorption, but also have rich functional groups to facilitate the fixation of biological molecules. A novel nanocomposite was synthesized herein through modification polyCBMA onto conducting polymer polyaniline (PANI) nanowire surface. The prepared polyCBMA/PANI composite, integrating the good conductivity of PANI nanowires with the excellent antifouling capability of polyCBMA, provided a wonderful matrix for the growth of ultrasensitive and low fouling biosensor. Carcinoembryonic antigen (CEA), an important biomarker for a variety of cancers, was utilized as a model test. Furthermore its antibody was fixed onto polyCBMA/PANI for the preparation of CEA biosensor. DPV was applied as a sensing principle with information at which peak potential and current the signals were recorded. The peak currents were in inverse proportion to the logarithm of CEA concentration in the range from 1.0×10-14gmL-1 to 1.0×10-10gmL-1, with a detect limit of 3.05fgmL-1. Furthermore, this low fouling, label-free biosensor has been utilized for assaying in undiluted human serum samples with resisting serious nonspecific protein adsorption, demonstrating its feasible potential application in clinical analysis of CEA.