Improving the Biocompatibility of Polymeric Membrane Potentiometric Ion Sensors by Using a Mussel-Inspired Polydopamine Coating

Abstract

Polymeric membrane potentiometric ion sensors have been widely used in clinical diagnosis for the detection of electrolyte ions and account for billions of measurements every year throughout the world. However, in many cases of practical relevance, biofouling, which might lead to sensor failure, usually occurs due to the lack of biocompatibility of these sensors. Herein, we describe a simple and robust approach for improving the biocompatibility of the polymeric ion-selective membranes. A marine mussel-inspired polydopamine polymer is used as a hydrophilic coating on the surface of conventional potentiometric ion sensors. Such a coating can be easily formed by self-polymerization of dopamine and robustly deposited on the sensor surface mimicking the adhesion mechanism of mussels. The classical poly(vinyl chloride) membrane-based calcium ion-selective electrode (ISE) is chosen as a model. Compared to the unmodified Ca2+ ISE, the polydopamine modified electrode shows a significantly reduced blood platelet adsorption while retaining original potentiometric ion response properties, which clearly indicates a high antifouling capability induced by the hydrophilic polydopamine coating. We believe that the proposed approach can provide an appealing way to improve the biocompatibility in the development of polymeric membrane electrochemical and optical sensors.