Study Of Bone And Cartilage Growth Factor Nanoparticles Of Release-Microspheres

Tissue engineering technology which made modern medicine step out of the scope of organ transplantion and enterd into a new era of organ reconstruction emerged in the1980s of last century. The technology of cartilage tissue engineering which serves as a important branch of tissue engineering developed fast and made progress in recent years. How ever, many key issues still needed to be resolved.Tissue engineering repair tissue organ damage technology including carrier support, seed cells, biological activity factor three basic elements. Active growth factor in the body short half-life, will soon be metabolism and dilution, and can’t meet the need of regeneration tissue repair. We developed the growth factor slow release microspheres, the aim is to extend the growth factor in the body, survival time for the application of tissue engineering cartilage damage repair lay the material foundation.Growth factors which are belong to protein substances are easy to be degraded by protease in vivo and cannot satisfy the need of tissue engineering for short half-life.It is necessary to prepare the sustained-release nanospheres containing a growth factor is to prolong their survival time in body, induce seed cell to differentiate and form bone or cartilage tissue. The purpose of this article is to create poly(hydroxybutyrate-co-hydroxyoctanoate) containing bone morphogenetic protein (rBMP) and make rBMP-PHBHOx sustained-release nanospheres which can provide growth factors for the bone layer of the joint integrative scaffold. Microspheres were prepared by electrospinning, solrent eraporatin and ultranic emulsification, respectively. Phacoemulsification nano microspheres were investigated by orthogonal test method for optimizing conditions preparation. The release properties of microspheres were investigated with PH7.4phosphate buffer as a medium in vitro. Nanosphere colloid was added into the bone tissue engineering scaffold by negative pressure method and the adhesion and compatibility were observed by electron microscopy. Microspheres prepared by Electrospinning method were larger and easy to make rBMP degenerate. The microspheres prepared by solvent evaporation method were easy to adhere together and form larger particles. The microspheres prepared by phacoemulsification were not only round but also smaller with good distribution. Optimized preparation conditions were as follows:density of PHBHOx was6.5%, Tween80was5%and Span80was1%, concentration of growth factors was10%, density of PVA was3%, the volume ratio of organic phase and aqueous phase was3tol. Microspheres technical parameters were as follows:average diameter was (564.75±53.46)nm, drug loading was (1.172±0.262) x10-2%, the encapsulation efficiency was (83.50±2.82)%, the in vitro release rate of13days up to87.89%. Microspheres were added to bone tissue engineering scaffold by negative pressure method. The results showed that microspheres were visible and had good property of adhesion on the scaffolds. rBMP-PHBHOx slow-release nano microspheres contained growth factor were prepared by phacoemulsification method in this paper. Results of these studies lay a certain foundation for the research of repairing the joint injury with integration stents.