Antifouling bismuth composite for robust electrochemical detection of heavy metals in complex matrices

Electrochemical detection of heavy metals in complex matrices, such as biofluids, food, and water, using bismuth-based composites allows for point-of-care diagnostics in healthcare, food safety, and environmental monitoring. However, challenges remain in commercialization, particularly due to electrode fouling and sensitivity loss. This study introduces a robust antifouling coating consisting of a 3D porous cross-linked bovine serum albumin (BSA) matrix and 2D g-C3N4, supported by conductive bismuth tungstate. This composite effectively prevents nonspecific interactions, enhances electron transfer, and maintains 90% of the signal after one month in untreated human plasma, serum, and wastewater. It enables sensitive and multiplexed detection of heavy metals in plasma, serum, and water, providing a simple, stable, and efficient solution for the development of electrochemical sensors. Electrode fouling is a liming factor for the electrochemical detection of heavy metals in complex matrices. Here, an antifouling composite coating based on bovine serum albumin, 2D g-C3N4 and bismuth tungstate maintains 90% signal after one month in untreated human plasma, serum and wastewater.