Development of N,O-Carboxymethyl Chitosan-Starch Biomaterial Inks for 3D Printed Wound Dressing Applications

In this paper, a novel hybrid biomaterial ink consisting of two water-soluble polymers is investigated: starch and N,O-carboxymethyl chitosan (NOCC). The biomaterial ink is used to fabricate controlled release biodegradable wound dressing scaffolds via a novel low-temperature solvent (organic)-free 3D printing technique. NOCC is a variant of chitosan with a high degradation rate that can lead to an immediate release of the drugs, and starch, on the other hand, is used to alter degradation and drug release characteristics of the biomaterial. Mupirocin, a topical anti-infective, is incorporated into the biomaterial inks. Different biomaterial inks in terms of NOCC to starch ratio are prepared and characterized. Printability and rheology of the samples are investigated, and the release of mupirocin over time is quantified. The efficacy of the developed 3D printed wound dressings against Staphylococcus aureus is examined through disk diffusion assays. Increasing NOCC accelerated the release of the drug from the scaffold and led to larger zones of inhibition in the early hours of the in vitro tests; this phenomenon is correlated to the enhanced hydrophilicity of NOCC-dominated scaffolds. The drug release and the zone of inhibition are controlled by altering starch to NOCC ratio in the biomaterial ink.