Bovine Serum Albumin-Cross-Linked Polyaniline Nanowires for Ultralow Fouling and Highly Sensitive Electrochemical Protein Quantification in Human Serum Samples.

Biofouling represents a serious challenge for the assaying of disease markers with various biosensors in complex biological samples due to the accompanied nonspecific protein adsorption. Herein, a highly sensitive and antifouling biosensing interface was constructed based on a cost-effective inert protein bovine serum albumin (BSA) cross-linked with polyaniline nanowires (PANI-NWs). Compared with the physically adsorbed BSA that was commonly used to block nonspecific adsorption or binding of proteins, the cross-linked BSA exhibited a significantly enhanced antifouling capability. The BSA/PANI-NW-modified electrode interface possessed excellent antifouling capability and electrochemical activity owing to the presence of the cross-linked BSA and the conducting polymer polyaniline. With further immobilization of the peptide aptamer for immunoglobulin G (IgG) recognition onto the BSA/PANI-NW interface, an electrochemical biosensor with excellent selectivity and sensitivity was prepared. The IgG biosensor possessed a linear range from 1.0 ng mL-1 to 10 μg mL-1 and a low detection limit of 0.27 ng mL-1, and it was capable of assaying IgG in complex human serum samples with acceptable accuracy when compared with the assay results obtained using commercial enzyme-linked immunosorbent assay kits. It is expected that the unique BSA-cross-linked conducting polymers can be used for the construction of various electrochemical sensors and biosensors that can be applied in complex biological media.