Effect of Adding Nanocrystalline Cellulose on Reducing Micro-Crack of Three-Dimensional Printed Hydroxyapatite/Collagen Composite

Large bone defects can not be recovered by self-repair meanwhile, bone scaffold with biomimetic material is needed. The biomimetic materials are hydroxyapatite/collagen as inorganic and organic material. The study on printed hydroxyapatite/collagen has been conducted. However, the crack occurred after printing and drying. The novelty of the research is addition of nanocrystalline cellulose (NCC) into the HA/collagen composite to reduce microcrack. The hydroxyapatite/collagen/NCC composite scaffold was printed with ۳D bioprinting which was a modification in bracket and cartridge with  print speed and layer height of ۱۰ mm/min and ۰.۵ mm. The cracking process that occurred in the hydroxyapatite/collagen material was investigated using Mi-View microscope. Furthermore, the scaffold of hydroxyapatite/collagen/NCC composite with composition ۷۰/۱۵/۱۵ (%w/v) was examined using the Vickers hardness test, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and thermogravimetric analysis/derivative thermogravimetry (TGA/DTG). After the printing process, shrinkage occurs on the X, Y, and Z axes with values of ۱۴, ۱۵.۱ and ۲۰.۵%. Moreover, the hardness value was  ۰.۰۰۲ to ۰.۰۰۳ HV with the detection of hydroxyapatite, collagen, and NCC. The crystallinity of hydroxyapatite/collagen/NCC was ۲۸%. The presence of NCC in the composite material can maintain a uniform three-dimensional network structure with a dominant composition of oxygen (۴۷.۷۷%), calcium (۳۶.۶۲%), and phosphate (۱۲.۸%). The TGA/DTG represented the amount of weight loss of ۲۳.۴۶% with an initial temperature of ۶۱۰ °C and maximum temperature of ۶۵۰ °C. Therefore, hydroxyapatite/collagen/NCC is  promising material for bone tissue engineering.

کلیدواژه ها:

۳D bioprinting based on extrusion ، Micro Crack ، Shrinkage ، Composite ، Nanocrystalline cellulose