Production of Hollow Bacterial Cellulose Microspheres Using Microfluidics to Form an Injectable Porous Scaffold for Wound Healing.

Bacterial cellulose (BC) is a biocompatible material with high purity and robust mechanical strength used to fabricate desirable scaffolds for 3D cell culture and wound healing. However, the chemical resistance of BC and its insolubility in the majority of solutions make it difficult to manipulate using standard chemical methods. In this study, a microfluidic process is developed to produce hollow BC microspheres with desirable internal structures and morphology. Microfluidics is used to generate a core-shell structured microparticle with an alginate core and agarose shell as a template to encapsulate Gluconacetobacter xylinus for long-term static culture. G. xylinus then secretes BC, which becomes entangled within the shell of the structured hydrogel microparticles and forms BC microspheres. The removal of the hydrogel template via thermal-chemical treatments yields robust BC microspheres exhibiting a hollow morphology. These hollow microspheres spontaneously assemble as functional units to form a novel injectable scaffold. In vitro, a highly porous scaffold is created to enable effective 3D cell culture with a high cell proliferation rate and better depth distribution. In vivo, this injectable scaffold facilitates tissue regeneration, resulting in rapid wound-healing in a Sprague Dawley rat skin model.

Near-infrared light triggerable deformation-free polysaccharide double network hydrogels.

To prepare a hydrogel with robust mechanical properties and programmable remotely-controlled releasing ability, we synthesized an agarose/alginate double network hydrogel incorporating polypyrrole (PPy) nanoparticles as a near-infrared (NIR) laser responsive releasing system. This hydrogel exhibited pulsatile releasing behaviours according to the laser switching while maintaining its morphology and mechanical strength.