Albumin-based optical and electrochemical biosensors for PFAS detection: a comparison

The widespread industrial use of per- and polyfluoroalkyl substances (PFAS) have engendered the release of these manmade chemicals in the environment with harmful effects on animal and human health. To monitor PFAS levels in drinking waters, sensitive and versatile sensing strategies are urgently required. Since many perfluoroalkyl carboxylic acids, such as perfluorooctanoic acid (PFOA), are fatty acid-mimic, delipidated human serum albumin (HSA) can be applied as biorecognition element for the design of novel PFAS sensors. Here, two albumin-based biosensing strategies are described and compared: i) a lossy mode resonance (LMR) fiber optic one and ii) an impedimetric portable one developed on screen-printed electrodes. In both biosensing platforms, HSA was covalently immobilized via EDC/NHS chemistry using the carboxylic moieties of the polymeric layers previously deposited at the transducer surface. Afterwards, the conformational changes related to the formation of HSA/PFOA complex were followed considering: i) the LMR spectral shifts for the optical platform and ii) the changes of absolute impedance for the impedimetric one. The performance and future developments of both PFOA biosensors are discussed.