A double cross-linked hydrogel based on water-soluble chitosan and oxidized hyaluronic acid as an antibacterial dressing

Quaternary ammonium chitosan (QCS) is a cationic polymer with high antimicrobial properties, but its cations can cause damage to normal cells. Thus, the biocompatibility of QCS in hydrogel dressings should be concerned. In this study, QCS was used as an additive in the preparation of the carboxymethyl chitosan (CMC) and oxidized hyaluronic acid (OHA) hydrogel, and the effect of its content in the hydrogel on antibacterial and biocompatibility was systematically investigated. First, QCS was mixed at a different ratio with CMC to form a QCS/CMC solution. Then, the QCS/CMC solution was added into the OHA solution to obtain the OHA-CMC/QCS hydrogel, which is a double cross-linked network formed by the Schiff base and electrostatic interaction. With the increase of the QCS content in the hydrogel, its mechanical and antibacterial properties were enhanced. The antibacterial rate of OHA-CMC/QCS5 hydrogel with 5% QCS content against Staphylococcus aureus reached 99.80%, and it also showed biocompatibility under the experimental conditions. This work provides a theoretical basis for the use of QCS to prepare the hydrogels that are both antibacterial and biocompatible. The prepared OHA-CMC/QCS5 hydrogel is an ideal candidate for antimicrobial dressings.