Synchronizing nonfouling and antimicrobial properties in a zwitterionic hydrogel

In this work, we report a new approach to integrate antimicrobial and nonfouling properties into a single platform without compromising each other. To achieve this, a zwitterionic hydrogel is conjugated with an antimicrobial agent as a leaving group in a way that maintains the zwitterionic form of the hydrogel before, during and after drug release, preventing bacteria surface adhesion and bulk proliferation simultaneously. The antibacterial salicylate anion contributes the negative charge to the initial zwitterionic state and is released through the ester linkage hydrolysis. The hydrogel then switches to its final zwitterionic state with the carboxylate as its new negatively charged group. We prove that this hydrogel can reach one-salicylate-per-monomer drug loading while still retaining the nonfouling property at protein and bacteria levels. It was also shown that its drug release profile was dictated by the hydrolysis rate of the monomer, making it possible to control and tailor the release rate of small hydrophilic drugs from the highly hydrated nonfouling polymer matrix.