Multifunctional layer-by-layer modified chitosan/poly(ethylene glycol) hydrogels

We report the surface modification of chitosan/poly(ethylene glycol) (chitosan/PEG) hydrogel materials via layer-by-layer (LbL) technique using stimuli-responsive polymers. Water-soluble complexes of Tannic Acid (TA) and a broad-spectrum antibiotic, Ciprofloxacin (Cipro) were prepared and co-assembled at the surface of Chitosan/PEG hydrogels with poly(N-vinyl caprolactam) (PVCL). Compared to the bare hydrogels, the surface spreading and proliferation of human fibroblasts were significantly enhanced on precast hydrogels coated with TA-Cipro/PVCL multilayers. LbL coating also provided enhanced Cipro release from the hydrogel surface at 37 degrees C compared to bare hydrogels. TA-Cipro/PVCL coated hydrogels showed antibacterial activity through chitosan and temperature-induced release of Cipro from multilayers. Chitosan and Cipro showed a coordinated antibacterial effect on Eschericia coli and Bacillus cereus, reducing their minimum inhibitory concentration (MIC). This effect was more pronounced on B. cereus. LbL modification of chitosan-based hydrogels using stimuli responsive polymers can be advantageous for bringing multiple functionalities to these materials without sacrificing their intrinsic properties such as antibacterial activity and biocompatibility. Such LbL-coated hydrogels hold promise in wound treatment as they may promote fibroblast proliferation and skin tissue regeneration.