Dual Growth Factors From Injectable Chitosan

Bone tissue has certain self healing abilities after an injury; providing that the impairment is mild and the defect size is small; Local administration of platelet deriving growth factor BB (PGDF-BB) and bone morphogenetic protein-2 (BMP-2) in a sequential release manner could substantially promote bone healing.

But clinical approaches to repairing large bone defects often involve the utilization of autografts and allografts; but these treatments have their own disadvantages. Nowadays, tissue engineering technique has emerging as an option for bone repair; Platelet deriving growth factor (PDGF) and bone morphogenetic protein-2 (BMP-2) are commonly using growth factors for bone fracture repair.

Dual Growth Factors

BMP-2 has been utilizing for the treatment of tibial fractures and for the lumbar spinal fusion by employing absorbable collagen sponge (ACS) as a carrier. Although the BMP-2-incorperating ACS set is clinically viable for fracture repair; its drawbacks can result in hypertrophic or atrophic non unions.

BMP-2 is knowing to be capable of reprograming some types of myoblasts through the transdifferentiation pathway. In this study, a biological assay basing on the BMP-2-induced ALP synthesis in C2C12 cells was used for detecting the activity of the releasing BMP-2; since BMP-2 has the ability to reprogram C2C12 cells to an osteogenic lineage; Chitosan (CH) polylactide (PLA) copolymers with free amino groups.

Fabricating ion

But which are soluble characters in water basing solvents finding to be suitable for fabricating ion crosslinking core shell microsphere that can carry BMP-2; PDGF-BB-loading alginate MPs were also successfully preparing by using calcium ions as a crosslinker.

But my composite gels that are constructing by embedding the PDGF BB loading alginate MPs and the BMP-2-loading core shell MPs into the CH/glycerophosphate hydrogel at optimal compositional proportions are finding to be injectable at ambient temperatures; and showing phase transition features near physiological temperature and pH; In addition, these composite gels were capable of effectively maintaining the bioactivity of the loaded factors. The optimzing composite gels have potential for applications in bone repair by sequentially providing growth-promoting cues for bone regeneration.