Creating Anti‐Biofouling Surfaces by Degradable Main‐chain Polyphosphoester Polymer Brushes

Abstract The implementation of polymer brush coatings has proven crucial in biomedical and biotechnological applications for controlling biological interactions. Despite the extensive research and use of synthetic polymer coatings, concerns regarding their long‐term non‐biodegradability have arisen. This issue is significant as non‐degradable polymers can lead to complications such as inflammatory responses and bioaccumulation, highlighting the need for polymers that degrade in a controlled manner. To address this, polyphosphonate brushes are synthesized as anti‐biofouling coatings on silicon surfaces via controlled surface‐initiated organocatalytic ring‐opening polymerization (SI‐ROP) of cyclic phospholanes. 2‐Ethyl‐2‐oxo‐1,3,2‐dioxaphospholane and 2‐hexyl‐2‐oxo‐1,3,2‐dioxaphospholane are chosen as the monomers to prepare hydrophilic and hydrophobic brushes with thicknesses up to 55 nm, with a proven degradability in aqueous media. In addition, protein adsorption, bacterial adhesion, and biofilm formation are investigated as a function of the polyphosphonate side chain. Compared to non‐coated surfaces and polyester brushes, hydrophilic poly(2‐ethyl‐2‐oxo‐1,3,2‐dioxaphospholane) brushes have an enhanced resistance toward fouling of albumin, fibrinogen, and diluted human serum proteins, as well as toward Escherichia coli and Staphylococcus aureus bacteria. The stability and anti‐biofouling performance of hydrophilic polyphosphonate brushes position them as an attractive option as degradable materials for anti‐biofouling matrices on medical devices and/or lubricious coatings for artificial implant technologies.