Injectable self-healing supramolecular hydrogels with conductivity and photo-thermal antibacterial activity to enhance complete skin regeneration

Hydrogel dressings with good biocompatibility and the ability to maintain a moist environment at the wound site have great potential for clinical application. Multifunctional injectable self-healing supramolecular hydrogel with conductivity and photo-thermal property as wound dressing to promote wound healing has been not reported. Herein, a series of antibacterial, injectable self-healing and conductive supramolecular hydrogels were fabricated through host-guest interaction based on quaternized chitosan-graft-cyclodextrin (QCS-CD), quaternized chitosan-graft-adamantane (QCS-AD) and graphene oxide-graft-cyclodextrin (GO-CD) polymer solutions which combined the good antibacterial activity of QCS and photo-thermal property of reduced graphene oxide (rGO). These supramolecular hydrogels wound dressings have a conductivity value similar to that of the skin and a rapid self-healing behavior, and have great antibacterial property against E. coli (gram-negative), S. aureus (gram-positive), and multi-drug resistant bacteria (such as Methicillin-resistant Staphylococcus aureus, MRSA). Furthermore, QCS-CD-AD/GO4 (0.4 wt% of rGO in the sample) shows a good balance between antibacterial activity, cell proliferation and hemocompatibility. Compared with commercial dressings (Tegaderm™ film) and QCS-CD-AD/GO0, the hydrogel QCS-CD-AD/GO4 significantly accelerated the in vivo healing process of full-thickness wounds with promoted epidermis and granulation tissue thickness, increased area coverage of collagen, and up-regulated VEGF expression. In short, these antibacterial, conductive self-healing supramolecular hydrogels are promising biomaterials as wound dressings for full-thickness skin repair.