Biomimetic materials assembled on a photovoltaic cell as a novel biosensing approach to cancer biomarker detection.

This work describes for the first time the integration of Dye Sensitized Solar Cell (DSSC) technology in biosensors and biomimetic materials, opening doors towards a new dimension of autonomous screening devices that may be used in point-of-care, with zero-power requirements. DSSCs are fabricated with a counter electrode (CE) of polypyrrole (PPy) that was made responsive to a specific protein by biomimetic material (BM) technology. Carcinogenic embryonic antigen (CEA) was selected as target protein. The resulting BM-PPy film acted as biomimetic artificial antibody for CEA. Rebinding of CEA into this film changed its intrinsic electrical properties and the subsequent electrical output of the DSSC using it as CE. The quantity of CEA in solution was deduced by I-V and electrochemical impedance spesctroscopy (EIS). Linear responses to CEA were observed down to 0.25 pg/mL, with 0.13 pg/mL detection limit. Control films of PPy (prepared without CEA in the electropolymerization step) confirmed the ability of the BM material to recognize the target protein. Accurate results were obtained in the analysis of urine samples. Further developments into this ground-breaking self-powered biosensor will display a huge impact in point-to-care medical applications, which may be extended to other fields of knowledge.