Functionalization of bacterial nanocellulose-based wound dressing for increased drug retention

Bacterial nanocellulose is a fascinating biopolymer with immense application potential, including as a wound dressing material. It is highly biocompatible and capable of keeping humidity needed for wound healing. However, it lacks specific affinity to pharmaceuticals to be delivered in a controlled fashion in a topical application, urged by the necessity to decrease the release of medicines to the environment. Solving this problem requires tailoring of the material functionality by chemical modification. In this work, a two-step strategy applying first phosphorylation and then introduction of biocompatible mineral particles was applied. Surface modification of commercially available wound dressing material based on dried bacterial nanocellulose led to phosphate grafting of 1.5–1.8 mmol/g and then uniform coverage of individual fibers (colloidal TiO2) or formation of aggregated platelets (TiBALDH®) on the surface (with Ti:P element ratios 0.45–0.80). To the titania functionalized dressing the broad spectrum antibiotic Tetracycline was bound (41–45 mg g-1) with its release delayed over several hours / days (over 50 % in 120 h for both nanocarriers). Biological essays indicated excellent biocompatibility and improved cell adhesion, offering a path to accelerated wound closure, promising for diverse tissue engineering applications. This study demonstrated a strategy in approach to dressing materials with delayed drug release properties exploiting the affinity of pharmaceuticals to mineral nanoparticles.