Chelation-Induced\nZwitterion-like Antifouling Behavior\non Anionic Poly(3,4-ethylenedioxythiophene) Surfaces

Antifouling properties are crucial for enhancing the\nlongevity\nand functionality of biomedical implants, drug delivery systems, and\nbiosensors. Zwitterionic polymers are renowned for their exceptional\nsurface hydration and charge neutrality, which effectively resist\nbiomolecular adsorption and protein attachment. We propose an innovative\napproach to develop zwitterion-like antifouling surfaces by chelating\ndivalent cations with anionic poly(3,4-ethylenedioxythiophene) (PEDOT)\nfilms, specifically PEDOT–PO<sub>4</sub> and PEDOT–COOH.\nThe chelation behavior of these films was systematically evaluated\nusing Na<sup>+</sup>, Mg<sup>2+</sup>, and Ca<sup>2+</sup> ions. Divalent\nions, particularly Ca<sup>2+</sup> and Mg<sup>2+</sup>, exhibit a\nstrong affinity for the anionic groups, leading to significant antifouling\nproperties. These modified surfaces effectively repelled both negatively\ncharged bovine serum albumin (BSA) and positively charged lysozyme\n(LYZ) proteins across various pH environments. This study offers valuable\ninsights into the antifouling characteristics of charged surfaces,\nenhancing our understanding of how ion-mediated surface modifications\ninfluence protein adsorption and interactions.