Immobilization of bone morphogenetic protein-2 to gelatin/avidin-modified hydroxyapatite composite scaffolds for bone regeneration

Abstract

Bone scaffold surface characterization is important for improving cell adhesion, migration, and differentiation. In this study, bone morphogenetic protein-2 (BMP-2) was immobilized to the surface of the gelatin/hydroxyapatite composite using avidin–biotin binding system to produce a bone-tissue engineering scaffold. Firstly, hydroxyapatite particles reacted with hexamethylene diisocyanate and then the terminal group was converted into a primary amine group. Avidin was then immobilized on the surfaces of hydroxyapatite particles using N-ethyl-N′-(3-(dimethylamino)propyl) carbodiimide and N-hydroxysuccinimide as coupling agents. Gelatin was blended with avidin-modified hydroxyapatite and pure hydroxyapatite to obtain gelain/hydroxyapatite composite. The composite was then cross-linked with glutaraldehyde. Finally, biotin-conjugated BMP-2 was immobilized on the surface of the composite via avidin–biotin binding. In vitro study indicated that BMP-2-immobilized composite film had a higher ALP activity than that composite film without BMP-2. The composite scaffolds were then implanted into rabbit skulls to check bone-tissue regeneration. Ultrasound and micro-CT scans demonstrated that neovascularization and new bone formation in the BMP-2-immobilized composite scaffolds were higher than those in composite scaffolds without BMP-2. Histological evaluation result was similar to that of the micro-CT. Therefore, the surface immobilization of BMP-2 could effectively improve osteogenesis in the gelatin/hydroxyapatite composite scaffold.

Remodeling Effects of the Combination of GGT Scaffolds, Percutaneous Electrical Stimulation, and Acupuncture on Large Bone Defects in Rats

“…In previous studies, we developed a TCP-crosslinked gelatin scaffold and a bone morphogenetic protein-2 (BMP-2)-immobilized gelatin/HA composite for promoting bone regeneration ( Lin et al, 1998 ; Cheng et al, 2019 ). To investigate the effect of physical treatments, we also developed a method to remodel bone tissues via ES treatment, indicating that ES treatment stimulates bone tissue regrowth after 12 weeks ( Yang et al, 2013 ).…”

Generating a High Valency Biotin Binder by Selecting Uniform Protein Assemblies via Crystallization

“…Many studies employ the avidin-biotin system as specific molecular glue and would benefit from the added binding sites and consequent binding capacity. A relevant system became recently apparent where avidin was used in bone-tissue engineering studies [41].…”

Strategies to Control or Mimic Growth Factor Activity for Bone, Cartilage, and Osteochondral Tissue Engineering

“…EDC mediates the reaction between a carboxylic acid and an amine to form a stable amide bond between the GF and the substrate surface. It has been used to conjugate TGF-β1, , TGF-β3, , BMP-2, ,− and BMP-4 , to a variety of biomaterials. SMCC links amines and thiols and has been used to conjugate TGF-β1 , and BMP-2. ,,,, …”