Fabrication and investigation of a biocompatible microfilament with high mechanical performance based on regenerated bacterial cellulose and bacterial cellulose

•Bacterial cellulose nanocrystals (BCNCs) with a highly oriented nanofibril bundle structure have been prepared.•A secondary hyperfine structure consisting of nanofibrils with diameters of just several nanometers has been investigated.•A novel strategy involving partial dissolution BC greatly enhanced the mechanical performance of the spun filaments.•A post-treatment process was utilized to remove residual solvents from the RBC/BC fibers to ensure biocompatibility.

A high-strength regenerated bacterial cellulose (RBC)/bacterial cellulose (BC) microfilament of potential use as a biomaterial was successfully prepared via a wet spinning process. The BC not only consists of a 3-D network composed of nanofibers with a diameter of several hundred nanometers but also has a secondary structure consisting of highly oriented nanofibrils with a diameter ranging from a few nanometers to tens of nanometers which explains the reason for the high mechanical strength of BC. Furthermore, a strategy of partially dissolving BC was used and this greatly enhanced the mechanical performance of spun filament and a method called post-treatment was utilized to remove residual solvents from the RBC/BC filaments. A comparison of structure, properties, as well as cytocompatibility between BC nanofibers and RBC/BC microfilaments was achieved using morphology, mechanical properties, X-ray Diffraction (XRD) and an enzymatic hydrolysis assay. The RBC/BC microfilament has a uniform groove structure with a diameter of 50-60 μm and XRD indicated that the crystal form was transformed from cellulose Iα to cellulose IIII and the degree of crystallinity of RBC/BC (33.22%) was much lower than the original BC (60.29%). The enzymatic hydrolysis assay proved that the RBC/BC material was more easily degraded than BC. ICP detection indicated that the residual amount of lithium was 0.07 mg/g (w/w) and GC-MS analysis showed the residual amount of DMAc to be 8.51 μg/g (w/w) demonstrating that the post-treatment process is necessary and effective for removal of residual materials from the RBC/BC microfilaments. Also, a cell viability assay demonstrated that after post-treatment the RBC/BC filaments had good cytocompatibility.

Graphical abstractDownload high-res image (207KB)Download full-size image