Preparation Technique, Characterizationand Biological Effects Of Nanoparticles As VEGF-P(HB-HO)

Repair of articular cartilage damage has been plagued by a major medical problem.The emergence and development of tissue engineering makes it possible to repairarticular cartilage. Currently in bone tissue engineering, the carrier bracket, seedcells and bioactive factors have become recognized as the three most importantfactors.Biological activity itself is mostly protein can easily be degraded by proteases invivo, in a short time will be metabolized, thus repairing the organization itself cannot be fully met, growth factor release microspheres can repair tissue engineeringtechnology pave the way for cartilage damage.Temporal control of bioactive signals in tissue engineering is greatly desired.In thisstudy,microspheres-based PHBHO(poly3-hydroxybutyrate-co-3-hydroxyoctanoate)ofencapslaed VEGF(vascular endothelial growth factor) were produced using threedifferent Particle Fabrication technique (electrospinning technique,solventevaporation technique,ultrasonic emulsification technique). Protein probablydenaturation and microspheres diameter was average10um by electrospinningmethod. microspheres adhere by solvent evaporation method.microspheres-particlesize distribution uniform, better dispersion are fabricated by ultrasonic emulsificationmethod.Mean diameter was detected by SEM(scanning electron microscopy),thenanospheres’diameter were524.75±67.46nm,The drug loading amount andencapsulation efficiency of VEGF-P(HB-HO)Ns were （1.397±0.018）×10-3%and90.77±1.67%, VEGF-P(HB-HO)NPs can not only sustain release VEGF,but also the vitro release profile displayed that nearly87.89%in the first13days.ThenVEGF-P(HB-HO)NPs were dropped in tissue engineering scaffolds or tissueengineering scaffolds were immersed in VEGF-P(HB-HO)NPs emultions,thescaffolds detected by SEM,the results showed that nanospheres adhesioned to tissueengineering scaffolds and distributed uniform.microspheres-based PHBHO(poly3-hydroxybutyrate-co-3-hydroxyoctanoate) of encapsulated VEGF(vascularendothelial growth factor) were prepared using ultrasonic emulsification technique,and evaluated its biological effects on cultured rabbit renal microvascular endothelialcells. Renal microvascular endothelial cells were cultured by three-step gradient meshmethod. MTT colorimetric assay were used to evaluate the proliferation of the renalmicrovascular endothelial cells according to the different culture mediumingredients,experiment groups were divided into three groups: simple culture mediumby adding VEGF (A group), adding VEGF-P (HBHO) NPs (B group), the onlyDMEM culture group (C group). Effective concentration of the first two groups wereset to10,20,50ng/ml, and five time points of each concentration was tested by MTTmethod. The results were analyzed by statistical software (SPSS13.0). During the first3days,the proliferation renal microvascular endothelial cells between group A and Bhad no significance(P>0.05), but much faster than group C(P＜0.01﹚;After3to7days,between A group and B group had significance(P＜0.01);7to10days,between Band A,C become much more significant(P＜0.01),but A and C had nosignificance(P>0.05).So VEGF-P (HBHO) NPs release had a more significantbiological effects than simple VEGF,and could continue to promote theirproliferation.