'Catch and Release' Polymeric Fibers: Versatile Interfaces for Engineering Reversible Platforms for Biomolecular Immobilization and Antibacterial Coatings.

Stimuli-responsive polymeric fibers have emerged as an indispensable material for numerous biomedical applications. Strategies to conjugate functional molecules with high specificity onto these nanofibers are vital to tailor these materials for specific applications. When the functionalization is reversible, these materials can serve as a 'catch and release' platform, which widens their applicability. Herein, polymeric fibers with an average diameter of about 237 ± 44 nm, amenable to reversible conjugation, are fabricated using electrospinning. The thiol-disulfide exchange reaction is employed to functionalize the electrospun fibers with thiol-containing functional molecules ranging from fluorescent dyes to bioactive ligands for protein immobilization. It is demonstrated that the linked (bio)molecules can be efficiently released in the presence of a thiol-containing reducing agent. Specifically, pyridyl disulfide (PDS)-containing copolymers are synthesized using a thiol-reactive PDS-based monomer, methyl methacrylate, and poly(ethylene glycol) methacrylate, where the monomers enable thiol-based specific functionalization, stable fiber formation, and anti-biofouling characteristics, respectively. After demonstrating efficient functionalization and release using fluorescent dyes and bioactive ligands, these fibers are conjugated with a thiol-containing cationic antibacterial peptide. It is demonstrated that the released peptide preserves its antibacterial activity against planktonic bacteria as well as biofilms. One can envision that the facile fabrication, efficient functionalization, and on-demand release attribute of these reversibly functionalizable polymeric fibers disclosed here would be attractive platforms for a wide range of biomedical applications.