Frontiers of Hydroxyapatite Composites in Bionic Bone Tissue Engineering

Abstract

Bone defects caused by various factors may cause morphological and functional disorders that can seriously affect patient’s quality of life. Autologous bone grafting is morbid, involves numerous complications, and provides limited volume at donor site. Hence, tissue-engineered bone is a better alternative for repair of bone defects and for promoting a patient’s functional recovery. Besides good biocompatibility, scaffolding materials represented by hydroxyapatite (HA) composites in tissue-engineered bone also have strong ability to guide bone regeneration. The development of manufacturing technology and advances in material science have made HA composite scaffolding more closely related to the composition and mechanical properties of natural bone. The surface morphology and pore diameter of the scaffold material are more important for cell proliferation, differentiation, and nutrient exchange. The degradation rate of the composite scaffold should match the rate of osteogenesis, and the loading of cells/cytokine is beneficial to promote the formation of new bone. In conclusion, there is no doubt that a breakthrough has been made in composition, mechanical properties, and degradation of HA composites. Biomimetic tissue-engineered bone based on vascularization and innervation show a promising future.

Electrospinning Inorganic Nanomaterials to Fabricate Bionanocomposites for Soft and Hard Tissue Repair

“…Hydroxyapatite (HA, Ca 10 (PO 4 ) 6 (OH) 2 ) exhibits structure and composition similar to that of natural apatite found in bone tissues and, owing to its high mechanical strength and biocompatibility, it is widely used as a scaffold material for bone TE. However, HA may have several drawbacks as a scaffold material, including a mismatch between the degradation rate and new bone formation as well as the low porosity and plasticity of the scaffolds, which impede its widespread use [ 95 , 96 ].…”

“…For bone TE, HA composites have been shown to exhibit compressive strength between 2 to 230 MPa and modulus of elasticity in the range of 0.05 to 30 GPa, thereby matching the mechanical properties of bone tissues. In addition, the scaffolds displaying pore sizes above 50 μm and degradation period between 2 to 6 months have been shown to facilitate cellular infiltration and angiogenesis for bone TE [ 95 ]. As mentioned above, despite good potential of hybrid scaffolds solely fabricated by using natural/synthetic polymers, additional candidates, such as inorganic NMs may be harnessed to further ameliorate the limitations associated with these scaffolds as well as confer additional bioactivity to scaffolds.…”

Three-Dimensional Plotted Calcium Phosphate Scaffolds for Bone Defect Augmentation—A New Method for Regeneration

“…Considering the absorbability, it was observed that a fast resorbing calcium phosphate bone substitute was directing the structural alterations of the host bone to vital bone tissue in a radiographical study [ 5 ]. It was stated that the optimal degradation rate of the scaffold is similar to the rate of osteogenesis [ 6 ]. Thus, the scaffold’s structure would be replaced by new bone.…”

Mussel-inspired HA@TA-CS/SA biomimetic 3D printed scaffolds with antibacterial activity for bone repair

“…Moreover, bioactive scaffolds avoid the drawbacks of traditional bone repair procedures, such as lack of bone cells and immune rejection, which can considerably reduce the patient’s suffering from bone diseases ( O'Brien, 2011 ; Delloye et al, 2007 ). The ideal scaffold is also required to have superior osteoinductivity, matching the new bone production rate’s degradation rate, mechanical strength compatible with the original bone, etc., ( Lee et al, 2022 ; Shi et al, 2022 ). Generally, bone tissue engineering scaffolds are available in four categories: natural polymers, synthetic polymers, bioceramic materials, and composite biomaterials ( Boos et al, 2010 ; Lee et al, 2022 ; O'Brien, 2011 ; Zhang et al, 2019 ).…”