Objective To review the research progress of growth factor sustained-release microspheres in fat transplantation. Methods The recently published 1iterature at home and abroad related the growth factor sustained-release microspheres in fat transplantation was reviewed and analyzed. Results The sustained-release microsphere carrier materials include natural polymer materials and synthetic polymer materials.The sustained-release complexes of different microsphere materials with different growth factors can promote the vascularization of transplanted fat in a timely manner, improve the survival rate of grafts, and reduce the incidence of complications such as liquefaction, calcification, and necrosis. Conclusion The growth factor sustained-release microspheres have the characteristics of persistence and controllability, which is a research hotspot in the field of fat transplantation and has broad application prospects.
Objective To evaluate the effect of the local del ivery of basic fibroblast growth factor 2 (bFGF-2) on the osseointegration around titanium implant of diabetic rats. Methods The bFGF-2-loaded poly (lactic-co-glycol ic acid) microspheres were prepared by water/oil/water (W/O/W) double-emulsion solvent evaporation method. Thirty-five male SPF level Sprague Dawley rats, weighing 220-250 g and aged 9 weeks, were selected as experimental animals. Ten rats were fedwith the routine diet as normal control group. The other 25 rats were made the diabetic animal model by giving high fat-sugar diet and a low dose streptozotocin (30 mg/ kg) intravenously; 20 rats were made the diabetic animal model successfully. Then 20 rats were randomly divided into diabetic control group (n=10) and bFGF-2 intervention group (n=10). A hole was drilled in the right tibia bone of all rats, and the titanium implant treated by micro-arc oxidation surface was planted into the hole. Simultaneously, the previously prepared microspheres and blood were mixed and were loaded on the surface of the implant before it was implanted into the rats of the bFGF-2 intervention group. At 4 and 8 weeks, the tibia containing implants was harvested, embedded with resin and made undecalcified tissue sl ices to compare the osseointegration. Results At 4 weeks, the implants of the normal control group were surrounded by new lamellar bone with continuity; whereas the tissue around the implants of the diabetic control group contained l ittle woven bone and some fibrous tissue; and obvious new formed bone with continuity was observed in bFGF-2 intervention group. At 8 weeks, the results of 3 groups were similar to those at 4 weeks. At 4 weeks, the percentage of bone-implant contact (BIC) in diabetic control group was significantly less than those in normal control group (P lt; 0.05) and in bFGF-2 intervention group (P lt; 0.05); the BIC in bFGF-2 intervention group was less than in normal control group, but showing no significant difference (P gt; 0.05). After 8 weeks, the BIC in normal control group and in bFGF-2 intervention group were significantly greater than that in diabetic control group (P lt; 0.05), but there was no significant difference between bFGF-2 intervention group and normal control group (P gt; 0.05). Conclusion Local del ivery of bFGF-2 around titanium implants may improve the osseointegration in diabetic rats.
Objective To construct polyhydroxyalkanoate (PHA) microspheres loaded with bone morphogenetic protein 2 (BMP-2) and human β-defensin 3 (HBD3), and evaluate the antibacterial activity of microspheres and the effect of promoting osteogenic differentiation, aiming to provide a new option of material for bone tissue engineering. Methods The soybean lecithin (SL)-BMP-2 and SL-HBD3 were prepared by SL-mediated introduction of growth factors into polyesters technology, and the functional microsphere (f-PMS) containing BMP-2 and HBD3 were prepared by microfluidic technology, while pure microsphere (p-PMS) was prepared by the same method as the control. The morphology of microspheres was observed by scanning electron microscopy and the water absorption was detected; the release curves of BMP-2 and HBD3 in f-PMS were detected by ELISA kit. The antibacterial effect of microspheres in Staphylococcus aureus and Escherichia coli was tested with the LIVE/DEADTM BacLightTM bacterial staining kit; the biocompatibility of microspheres was tested using Transwell and cell counting kit 8 (CCK-8). The effect of microspheres on osteogenic differentiation was determined by collagen type Ⅰ (COL-1) immunofluorescence staining and alkaline phosphatase (ALP) concentration. Results In this experiment, the f-PMS and p-PMS were successfully constructed. Morphological characteristics showed that p-PMS surface was rough and distributed with micropores of 1-3 μm, while f-PMS surface was smooth and existed white granular material. There was no significant difference in water absorption between the two groups (P>0.05). The release curves of BMP-2 and HBD3 in the f-PMS and p-PMS were basically the same, showing both early sudden release and late slow release. The antibacterial activity of f-PMS was significantly higher than that of p-PMS in the test that against Staphylococcus aureus and Escherichia coli (P<0.05), but there was no significant difference in biocompatibility between the two groups (P>0.05). The results of osteogenic differentiation of human BMSCs showed that the fluorescence intensity of osteogenic specific protein COL-1 of f-PMS was significantly higher than that in p-PMS, and the activity of ALP in f-PMS was also significantly higher than that in p-PMS (P<0.05). Conclusion The p-PHA have good antibacterial activity and biocompatibility, and can effectively promote the osteogenic differentiation of human BMSCs, which is expected to be applied to bone tissue engineering in the future.
Calcium phosphate cement (CPC) has been widely used as bone fillers because of its excellent bioactivity and biocompatibility. Meanwhile, CPC is also an attractive candidate for the incorporation of drug or microspheres, because the preparing procedure avoids sintering and heating release. This paper summarizes the clinical applications of microspheres incorporated in CPC from the aspects of sustained drug release, accelerated degradation, porous structure and improved mechanical properties. The paper is aimed to analyze the methods and principles of microspheres loaded CPC, and so as to lay a foundation for the further research of improving and manufacturing the CPC with ideal properties.
Objective To investigate the preparation and properties of the novel silica (SiO2)/hydroxyapatite (HAP) whiskers porous ceramics scaffold. Methods The HAP whiskers were modified by the SiO2 microspheres using the Stöber method. Three types of SiO2/HAP whiskers were fabricated under different factors (for the No.1 samples, the content of tetraethoxysilane, stirring time, calcination temperature, and soaking time were 10 mL, 12 hours, 560℃, and 0.5 hours, respectively; and in the No.2 samples, those were 15 mL, 24 hours, 650℃, and 2 hours, respectively; while those in the No.3 samples were 20 mL, 48 hours, 750℃, and 4 hours, respectively). The phase and morphology of the self-made HAP whisker and 3 types of SiO2/HAP whiskers were detected by the X-ray diffraction analysis and scanning electron microscopy. Taken the self-made HAP whisker and 3 types of SiO2/HAP whiskers as raw materials, various porous ceramic materials were prepared using the mechanical foaming method combined with extrusion molding method, and the low-temperature heat treatment. The pore structure of porous ceramics was observed by scanning electron microscopy. Its porosity and pore size distribution were measured. And further the axial compressive strength was measured, and the biodegradability was detected by simulated body fluid. Cell counting kit 8 method was used to conduct cytotoxicity experiments on the extract of porous ceramics. Results The SiO2 microspheres modified HAP whiskers and its porous ceramic materials were prepared successfully, respectively. In the SiO2/HAP whiskers, the amorphous SiO2 microspheres with a diameter of 200 nm, uniform distribution and good adhesion were attached to the surface of the whiskers, and the number of microspheres was controllable. The apparent porosity of the porous ceramic scaffold was about 78%, and its pore structure was composed of neatly arranged longitudinal through-holes and a large number of micro/nano through-holes. Compared with HAP whisker porous ceramic, the axial compressive strength of the SiO2/HAP whisker porous ceramics could reach 1.0 MPa, which increased the strength by nearly 4 times. Among them, the axial compressive strength of the No.2 SiO2/HAP whisker porous ceramic was the highest. The SiO2 microspheres attached to the surface of the whiskers could provide sites for the deposition of apatite. With the content of SiO2 microspheres increased, the deposition rate of apatite accelerated. The cytotoxicity level of the prepared porous ceramics ranged from 0 to 1, without cytotoxicity. Conclusion SiO2/HAP whisker porous ceramics have good biological activity, high porosity, three-dimensional complex pore structure, good axial compressive strength, and no cytotoxicity, which make it a promising scaffold material for bone tissue engineering.
Objective To estimate the relationship between arterial blood ketone body ratio (AKBR) and liver function and to appraise the feasibility of adding AKBR into liver function estimate. MethodsFrom 1994 to 1998, 44 patients with unresectable liver cancer recieved the combined radiochemoembolization with mixed emulsion of phosphorus32 glass microspheres (32PGMS), chemoagent and glycerine or lipiodol, via intraoperative hepatic artery instillation, hepatic artery ligation and operational arterial embolization (HAL+OAE) or transcatheter hepatic artery embolization (TAE). Preoperative and postoperative function and energy change level of the liver were tested by liver function test and AKBR. CT, SPECT, AFP were used to judge the therapy effect; multivariate statistical analysis methods were used to evaluate the correlation between AKBR and liver function. Spearmen rank correlation analysis was used to evaluate whether there was any relationship between AKBR and liver function test, and to evaluate that there was any relationship between AKBR and survival time. ResultsA negative correlation showed between the level of AKBR and liver function. The correlation coefficient of the three level of AKBR before operation and survival time was 0.4409. Conclusion AKBR can well reflect the degree of liver function.
Objective To investigate the promotion effects of the collagen membrane incorporating bFGF impregnated microspheres on the wound healing of the pigskin losing its full-thickness layers. Methods The bFGF containing microspheres was added into the dry microspleres.The collagen membranes were prepared by incorporating bFGF-impregnated microspheres, and 6 York pig models of skin wounds with loss of their full-thickness layers were established for the ob servation of the effects on the wound healing. Results The healing time and the 28day healing rate were 27.30±1.14 days and 98.12%±1.97%, respectively.The healing rate was significantly higher and the healing time was significantl y shorter in the experimental group than in the control group (Plt;0.05). The histological examination showed that the proliferation condition of the epidermiswasalso much better in the experimental group. Conclusion Incorporation of bFGF-impregnated microspheres into the collagen membrane is a promising method of pro moting the healing of the wound with a loss of the fullthickness skin.
Objective To evaluate the suitability of the biodegradable microsphere encapsulation of adenovirus as a targeting vector for gene therapy of hepatocellular carcinoma. Methods Encapsulate the recombinant adenovirus in PLG 〔poly (lactic/glycolic)〕 copolymer by the solution evaporation method, the release test and the bioactivity of viruses incorporated in vitro were studied. Results More than 19.3% of adenovirus was encapsulated in PLG microspheres. The release test shows that the adenovirus was released for more than 200 h, 50% were shed within the first 100 h, and their activity was retained. Conclusion Recombinant adenovirus can be formulated in a polymer preparation of PLG with retention of bioactivity. It may be a valuable vector for the gene therapy of liver cancer.
Objective To study the outcomes of nerve defect repair with the tissue engineered nerve, which is composed of the complex of SCs, 30% ECM gel, bFGF-PLGA sustained release microspheres, PLGA microfilaments and permeable poly (D, L-lacitic acid) (PDLLA) catheters. Methods SCs were cultured and purified from the sciatic nerves of 1-day-old neonatal SD rats. The 1st passage cells were compounded with bFGF-PLGA sustained release microspheres andECM gel, and then were injected into permeable PDLLA catheters with PLGA microfilaments inside. In this way, the tissueengineered nerve was constructed. Sixty SD rats were included. The model of 15-mm sciatic nerve defects was made, and then the rats were randomly divided into 5 groups, with 12 rats in each. In group A, autograft was adopted. In group B, the blank PDLLA catheters with PBS inside were used. In group C, PDLLA catheters, with PLGA microfilaments and 30% ECM gel inside, were used. In group D, PDLLA catheters, with PLGA microfilaments, SCs and 30% ECM gel inside, were used. In group E, the tissue engineered nerve was appl ied. After the operation, observation was made for general conditions of the rats. The sciatic function index (SFI) analysis was performed at 12, 16, 20 and 24 weeks after the operation, respectively. Eelectrophysiological detection and histological observation were performed at 12 and 24 weeks after the operation, respectively. Results All rats survived to the end of the experiment. At 12 and 16 weeks after the operation, group E was significantly different from group B in SFI (P lt; 0.05). At 20 and 24 weeks after the operation, group E was significantly different from groups B and C in SFI (P lt; 0.05). At 12 weeks after the operation, electrophysiological detection showed nerve conduct velocity (NCV) of group E was bigger than that of groups B and C (P lt; 0.05), and compound ampl itude (AMP) as well as action potential area (AREA） of group E were bigger than those of groups B, C and D (P lt; 0.05). At 24 weeks after the operation, NCV, AMP and AREA of group E were bigger than those of groups B and C (Plt; 0.05). At 12 weeks after the operation, histological observation showed the area of regenerated nerves and the number of myel inated fibers in group E were significantly differents from those in groups A, B and C (Plt; 0.05). The density and diameter of myel inated fibers in group E were smaller than those in group A (Plt; 0.05), but bigger than those in groups B, C and D (P lt; 0.05). At 24 weeks after the operation, the area of regenerative nerves in group E is bigger than those in group B (P lt; 0.05); the number of myel inated fibers in group E was significantly different from those in groups A, B, C (P lt; 0.05); and the density and diameter of myel inated fibers in group E were bigger than those in groups B and C (Plt; 0.05). Conclusion The tissue engineered nerve with the complex of SCs, ECM gel, bFGF-PLGA sustained release microspheres, PLGA microfilaments and permeables PDLLA catheters promote nerve regeneration and has similar effect to autograft in repair of nerve defects.
The purpose of this study is to investigate the effect of superparamagnetic chitosan FGF-2 gelatin microspheres (SPCFGM) on the proliferation and differentiation of mouse mesenchymal stem cells. The superparamagnetic iron oxide chitosan nanoparticles (SPIOCNs) were synthesized by means of chemical co-precipitation, combined with FGF-2. Then The SPCFGM and superparamagnetic chitosan gelatin microspheres (SPCGM) were prepared by means of crosslinking-emulsion. The properties of SPCFGM and SPIONs were measured by laser diffraction particle size analyser and transmisson electron microscopy. The SPCFGM were measured for drug loading capacity, encapsulation efficiency and release pharmaceutical properties in vitro. The C3H10 cells were grouped according to the different ingredients being added to the culture medium: SPCFGM group, SPCGM group and DMEM as control group. Cell apoptosis was analyzed by DAPI staining. The protein expression level of FGF-2 was determined by Western blot. The proliferation activity and cell cycle phase of C3H10 were examined by CCK8 and flow cytometry. The results demonstrated that both of the SPIOCNs and SPCFGM were exhibited structure of spherical crystallization with a diameter of (25±9) nm and (140±12) μm, respectively. There were no apoptosis cells in the three group cells. Both the protein expression level of FGF-2 and cell proliferation activity increased significantly in the SPCFGM group cells(P<0.05). The SPCFGM is successfully constructed and it can controlled-release FGF-2, remained the biological activity of FGF-2, which can promote proliferation activity of C3H10 cells, and are non-toxic to the cell.