Environmentally friendly anti-biofouling polymeric membrane potentiometric sensors based on imprinted receptors

Polymeric membrane potentiometric sensors using molecularly imprinted polymer (MIP) receptors are an ideal tool for determination of organic ionic species. However, their applications in complicated samples are very limited because of occurrence of sensor biofouling. Herein, for the first time, we describe a simple but environmentally friendly strategy to improve anti-biofouling performance of MIP-based potentiometric sensors. The non-toxic, environmentally friendly anti-fouling agent is doped into the polymeric membrane. The released organic biocidal agent from the polymeric membrane can kill the microorganisms adhered to the sensing membrane surface, and the formation of biofilms can thus be prevented. As a proof-the-concept, an all-solid-state MIP-based potentiometric ceftiofur sensor is selected as a model. Capsaicin, a naturally occurring alkaloid derived from chillis, is chosen as a non-toxic biocide agent. Another widely used biocide agent 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) with low toxicity is also used as a comparison. Compared to the undoped electrode, the capsaicin-doped MIP sensor exhibits remarkably improved anti-biofouling abilities in terms of the low survival rate and the low adhesion rates of the bacterial cells and microalgae. Especially, the capsaicin-based electrode displays similar anti-fouling and response properties to the DCOIT-based one. It can be anticipated that such anti-fouling strategy may lay the foundation for development of “green” anti-fouling sensors, which are urgently required in marine monitoring and clinical diagnosis.