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.