Smart pH-Responsive Antimicrobial Hydrogel Scaffolds Prepared by Additive Manufacturing.

We report on the fabrication of 3D printed pH-responsive and antimicrobial hydrogels with a micrometer-scale resolution achieved by stereolithography (SLA) 3D printing. The preparation of the hydrogels was optimized by selecting the most appropriate difunctional polyethylene glycol dimethacrylates (testing cross-linking agents with chain lengths ranging from 2 up to 14 units ethylene glycol) and introducing acrylic acid (AA) as a monofunctional monomer. As a result of the incorporation of AA, the hydrogels described are able to reversibly swell and shrink upon environmental changes on the pH, and the swelling extent is directly related to the amount of AA and can be thus finely tuned.