Improving the mechanical, degradation properties and biocompatibility of nano-hydroxyapatite/chitosan composite scaffold by the introduction of carboxylated bamboo fiber

In this work, carboxylated bamboo fiber (BF) was first incorporated into nano-hydroxyapatite/chitosan (n-HA/CS) system to obtain a novel porous composite by freeze-drying method for bone tissue engineering scaffold. The results of infrared spectrometer analysis, scanning electron microscope observation, porosity and compressive strength test revealed that the ionic-crosslinking of carboxylated BF and CS played an important role in the formation of the composite scaffold with a highly orientation groove porous structure. Especially, when 30 wt% carboxylated BF was added, the compressive strength of n-HA/CS composite scaffold was enhanced up to over three times, and the porosity was still higher than 80%. Moreover, simulated body fluids soaking demonstrated that the introduction of carboxylated BF not only slowed down the degradation of n-HA/CS composite scaffold by the ionic-crosslinking, but also induced more apatite to deposit owing to the exposure of excessive carboxyl of carboxylated BF. Additionally, in vitro cell culture results indicated that the introduction of BF were helpful for cell compatibility. Conclusively, carboxylated BF endowed the scaffold with a highly interconnected orientation porous structure, excellent compressive strength, appropriate degradation and good biocompatibility, which would provide a new way for realizing high value-added applications of BF as a low-cost biomass resource.