[Preparation and examination of BMP-2 loaded chitosan nanospheres in vitro].
OBJECTIVE
To prepare chitosan nanospheres for loading of BMP-2 and to evaluate its size, zeta potential, appearance, degradation and release characteristic in vitro, and then to investigate its feasibility as a carrier for sustained release of BMP-2.


METHODS
The BMP-2 loaded chitosan nanospheres were prepared using ionic crosslinking method with tripolyphosphate (TPP) and chitosan. Transmission electron microscope was used to evaluate the morphological properties, and laser particle size analyzer was used to analyze particle size, Zeta potential and distribution. Lysozyme degradation experiment was performed to assess the biodegradation behavior. ELISA assay was used to determine the loading efficiency, encapsulation efficiency and in vitro drug release kinetics. The data was analyzed by SPSS 19.0 software package.


RESULTS
The BMP-2 loaded chitosan nanospheres were spherical in shape, smooth on surface and uniform dispersion without aggregation. The mean diameter was 150.85 nm. The dispersion index was 0.37, and zeta potential was +35.42 mV. The average loading efficiency and encapsulation efficiency were (56.83 ± 2.26)% and (68.24 ± 3.83)%, respectively. Release experiment in vitro showed that the releasing property of BMP-2 loaded chitosan nanospheres was consistent with two-phase kinetic regulation and BMP-2 was controlled to release from the chitosan nanospheres over 30 days.


CONCLUSIONS
The BMP-2 loaded chitosan nanospheres prepared by ionic crosslinking method are successfully prepared which show a good controlled release property. It provides the basis for further application in bone tissue engineering.
Department of Oral and Maxillofacial Surgery, The Affiliated Hospital of Qingdao University. Qingdao 266003, Shandong Province, China.E-mail:878995334@qq.com.
Feng
F
Liu
Jian
J
Sun
Ya-li
YL
Li
Li-qiang
LQ
Chen
Jing-sen
JS
Xie
Xiao-long
XL
Zang
D055396:Bone Morphogenetic Protein 2; D048271:Chitosan; D016503:Drug Delivery Systems; D066298:In Vitro Techniques; D054118:Nanospheres; D010316:Particle Size; D010599:Pharmacokinetics; D011122:Polyphosphates
C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D011122:Polyphosphates; D048271:Chitosan; C005692:triphosphoric acid