A physically crosslinked polydopamine/nanocellulose hydrogel as potential versatile vehicles for drug delivery and wound healing

In this study, we reported a pH/near-infrared (NIR)-responsive hydrogel for on-demand drug delivery and wound healing. Cellulose nanofibrils (TOCNFs) were produced by 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation method. Polydopamine (PDA) was introduced into TOCNFs network to fabricate a PDA/TOCNFs hydrogel through ion-crosslinking with calcium ion as a crosslinker. Then, tetracycline hydrochloride (TH) which loaded on PDA could be released from the prepared hydrogels in an on-demand fashion under NIR exposure or at lower pH conditions. In addition, the in vivo skin defect experiments illustrated that the resultant composite hydrogel had a synergistic effect on promoting wound healing. Therefore, owing to the unique pH/NIR responsiveness, long time period drug releasing property, antibacterial and mechanical properties, together with their biodegradability and biocompatibility, the prepared PDA/TOCNFs hydrogel is highly promising as a new drug delivery vehicle, offering simple and safe alternatives to the conventional systems based on the petroleum-based polymers.