LAUSR

Abstract Pursuing self-powered biosensors, this work describes a hybrid device combining a sensing electrochemical system with a photovoltaic cell. The sensing system is a molecularly-imprinted polymer (MIP) and the photovoltaic cell is a dye-sensitized solar cell (DSSC). The biosensing film is tailored on a typical counter electrode (CE) of a conventional DSSC, turning the resulting hybrid system sensitive to a target analyte. The target analyte selected herein was carcinogenic embryonic antigen (CEA), a typical cancer biomarker in colorectal cancer. In detail, the MIP film was tailored on a highly conductive polyaniline CE, by electropolymerizing aniline on top of it, in near basic pH and in the presence of CEA. The protein was later removed by proteinase K action. The resulting vacant sites were able to rebind CEA, as confirmed in a 3-electrodes set-up, by square-wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) studies. The hybrid DSSC/biosensing system was tested by incubating the CEA solution in urine sample on the biosensing film and using the resulting surface to act as counter electrode of the photovoltaic cell. The photovoltaic features of the resulting device confirmed the dependency between power and CEA concentration. In this new set-up, a linear trend was observed between power and log CEA concentration, down to 0.025 ng mL−1 when urine samples were tested. Overall, the hybrid device is inexpensive and self-powered, which holds a great impact in point-of-care applications, especially in low-income countries. This concept may be further extended to other biomarkers implicated in several diseases or other target molecules involved in food safety or environmental monitoring needs.