Polymeric membrane ion-selective electrodes with anti-biofouling properties by surface modification of silver nanoparticles

Abstract

Polymeric membrane ion-selective electrodes (ISEs) have been widely applied in environmental analysis. In many cases of practical relevance, however, when these sensors are applied in complex samples, they could suffer from problems of biofouling (related to microorganisms and biofilms) which may shorten the sensors’ lifetimes and cause the measurement errors. Herein, we describe a robust and effective method to endow the ISE membranes with anti-biofouling properties based on surface modification of silver nanoparticles (Ag NPs). The ISE membrane is modified with the hydrophilic polydopamine (PDA) followed by in-situ formation of Ag NPs. The PDA modification enhances anti-adhesive properties of the ISE membrane by increasing the surface hydrophilicity, while Ag NPs impart strong anti-microbial properties to the membrane. A classical polymeric membrane K+-ISE has been chosen as a model. Compared to the unmodified K+-ISE, the Ag NPs modified K+-ISE exhibits significantly improved anti-biofouling properties in terms of the low viability and adhesion rates of bacteria while retaining its original potentiometric ion response properties. Moreover, Ag NPs on the sensor surface show an excellent long-term stability. We believe that the proposed approach can be extended to improve the anti-fouling abilities of other polymeric membrane-based electrochemical sensors for detection in complex environmental samples.