Preparation and characterization of bamboo fiber/chitosan/nano-hydroxyapatite composite membrane by ionic crosslinking

To obtain an ideal guided bone tissue regeneration (GBR) membrane, carboxylated bamboo fiber (BF) was designed to be introduced into the chitosan/nano-hydroxyapatite (CS/n-HA) system by ionic crosslinking to fabricate a novel BF/CS/n-HA composite membranes with different weight ratios. The formation mechanism of the BF/CS/n-HA ternary composite membrane and the effect of BF different contents on the BF/CS/n-HA composite membranes were studied by Fourier Transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), electromechanical universal tester, in vitro soaking in simulated body fluid (SBF). Results demonstrated that CS and modified BF would be ionic crosslinked by electrostatic interaction to form a three dimensional polyelectrolyte structure, meanwhile, n-HA was loaded in the polyelectrolyte structure by hydrogen bonding, which ensured the modified BF/CS/n-HA composite membranes to possess excellent tensile strength, compared to the CS/n-HA and untreated BF/CS/n-HA composite membrane. Moreover, the weight ratio of the modified BF/CS/n-HA of 2:6:2 displayed the highest tensile strength, whose tensile strength was improved by over two folds than that of CS/n-HA composite membrane owing to the most suitable proportion. In addition, in vitro simulated body fluids soaking results indicated that the modified BF/CS/n-HA composite membranes presented different degradation rates and could promote the apatite to deposit by investigating the weight loss, water absorption rate, SEM morphology observation and tensile strength reduce. All results revealed that the ionic crosslinking of carboxylated BF and CS was conducive to fabricate BF/CS/n-HA composite membrane with higher mechanical property, more suitable degradation and better bioactivity, in contrast with the CS/n-HA and untreated BF/CS/n-HA composite membranes, which had a great promising to obtain more satisfactory GBR membrane, moreover, the study would provide a new application for natural BF in the biomedical membrane field. Graphic abstract In this manuscript, carboxylated bamboo fiber (BF) was designed to be introduced into the chitosan/nano-hydroxyapatite (CS/n-HA) system to fabricate a novel BF/CS/n-HA composite membranes with different weight ratios. The formation mechanism of the BF/CS/n-HA ternary composite membrane and the effect of modified BF different contents on the BF/CS/n-HA composite membranes were studied, and the main purpose of the study was to