ABSTRACT
BACKGROUND: Revascularization is a challenge for the tissue-engineered bone carrying cells after implanted into human body. Previous studies have found that tanshinol can improve the functions of endothelial progenitor cells and exert vascular protective effects.OBJECTIVE: To prepare the β-calcium phosphate (β-TCP) scaffold with tanshinol coating, and to observe its cytocompatibility.METHODS: The β-TCP scaffolds coated with 10-7, 10-6 and 10-5 mol of tanshinol were constructed by negative pressure absorption method. The distribution of tanshinol coating on the scaffold was observed using scanning electron microscopy,and the inner ingredients were analyzed by infrared spectrum. Human endothelial progenitor cells (hEPCs) were cultured in the extracts of β-TCP and β-TCP scaffolds with 10-7, 10-6, 10-5 mol of tanshinol coatings, respectively. The cell proliferation was detected at 2, 4, 6, 8 and 10 days of culture; the levels of nitric oxide and vascular endothelial growth factor in the supernatants were detected at 1, 7 and 14 days of culture; the lumen formation on the matrigel was observed after 14-day culture. hEPCs were respectively seeded onto the β-TCP and β-TCP scaffolds with different dosages of tanshinol coating,and then the cell growth was observed under scanning electron microscope at 7 days.RESULTS AND CONCLUSION: The tanshinol coating evenly distributed on the inner surface of the pores, and its crystalline structure became dense with dosage increasing. Infrared spectrum analysis revealed no changes in the characteristic absorption peak of tanshinol and TCP in the scaffold. The β-TCP scaffolds with tanshinol coating could promote the proliferation of hEPCs, especially the scaffolds with 10-6 and 10-5 mol tanshinol coating. Compared with the β-TCP scaffold, the scaffolds with 10-6 and 10-5 mol tanshinol coating significantly upregulated the nitric oxide level at 14 days of culture, and significantly increased the level of vascular endothelial growth factor at 7 and 14 days of culture (P <0.05). Although it could be found in all β-TCP scaffolds with tanshinol coating, the lumen formation was the maturest in the scaffold with 10-5 mol tanshinol coating. These results suggest the β-TCP scaffolds with tanshinol coating can promote the proliferation and endothelial differentiation of hEPCs, and hold a good cytocompatibility.
ABSTRACT
BACKGROUND:Col agen/bioactive glass composite materials possess excellent osteogenic potential and biocompatibility, but its application in bone tissue engineering is limited by mechanical property and degradation. OBJECTIVE:To construct col agen/bioactive glass/chitosan composite scaffolds with good mechanical property, anti-degradation ability and bone repair property. METHODS:Bioactive glass/col agen composite scaffolds with chitosan as dispersant were prepared by lyophylization. Fourier transform infrared spectroscopy, scanning electron microscope, X-ray diffraction, and dynamic biomechanical testing were used to characterize the structure and properties of the composite scaffolds. RESULTS AND CONCLUSION:Results show that charge-attractions in pre-prepared bioactive glass/chitosan solution increased the homogeneity of bioactive glass dispersed in col agen gel and the compressive modulus and strength increased significantly due to the homogeneity and intermolecular interactions between chitosan and col agen. The enzymatic degradation rate and mineralization activity in the simulated body fluid were also lower because of a high degree of embedment of bioactive glass in col agen/chitosan matrix, and entanglement of col agen in chitosan at molecular level, which decreased the exposure of bioactive glass to the simulated body fluid, and col agen to enzyme solution.
ABSTRACT
BACKGROUND:Research on ethyl pyruvate detection methods is reported rarely, and moreover, literature about reversed-phase high-performance liquid chromatography (RP-HPLC) for detection of ethyl pyruvate is less. OBJECTIVE:To establish an RP-HPLC method for determination of ethyl pyruvate in ethyl pyruvate-chitosan nanoparticles. METHODS: The chromatographic analysis was performed on a ZORBAX Eclipse XDB-C18 column (4.6 mm× 150 mm, 5μm) at 25℃, with the mixture of acetonitrile and water (40:60, V/V) as the mobile phase at the flow rate of 1 mL/min. The determination wavelength wasset at 210 nm and the injection volume was 20 μL. RESULTS AND CONCLUSION: The peak of ethyl pyruvate and the peaks of auxiliary materials and solvent were separated wel. The linear rang of ethyl pyruvate was 1-100 mg/L (r=0.999 6). The relative standard deviation of both the intra-and inter-day precision was less than 3% for low-, moderate-, and high-concentration ethyl pyruvate. The relative standard deviation of reproducibility test and stability test was 1.25% and 1.3%, respectively. Sample average recovery rates were (91.5±1.0)%, (3.5±0.2)%, (94.4±0.4)%, respectively. Encapsulation efficiency of samples were (87.2±0.22)%, (90.5±0.15)%, (91.1±0.17)%, respectively. The relative standard deviation of different sample content were 0.9%, 0.5%, 0.3%, respectively. The RP-HPLC method for determination of ethyl pyruvate is sensitive, accurate and highly specific with wide linear range and high sample average recovery.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the apatite forming ability of pure titanium implant after micro-arc oxidation treatment in simulated body fluid (SBF) and obtain implants with calcium phosphate (Ca-P) layers.</p><p><b>METHODS</b>The implants were immersed in (SBF) after micro-arc oxidation treatment for different time lengths, and their apatite forming ability and the morphology and constituents of the Ca-P layers formed on the sample surface were analyzed using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive electron probe.</p><p><b>RESULTS</b>After immersion in SBF, large quantities of Ca-P layers were induced on the surface of the samples. The Ca-P layers were composed of octacalcium phosphate and carbonated hydroxyapatite, and the crystals showed a plate-like morphology with an oriented growth.</p><p><b>CONCLUSION</b>The implants with micro-arc oxidation treatment show good apatite forming ability on the surface with rich calcium and phosphorus elements. The formed layers are composed of bone-like apatite including octacalcium phosphate and carbonated hydroxyapatite.</p>
Subject(s)
Apatites , Chemistry , Biomimetic Materials , Chemistry , Body Fluids , Chemistry , Calcium Phosphates , Chemistry , Coated Materials, Biocompatible , Chemistry , Durapatite , Chemistry , Oxidation-Reduction , Prostheses and Implants , Random Allocation , Surface Properties , Titanium , ChemistryABSTRACT
BACKGROUND: The contact lenses were easily contaminated by adsorbing components from the tear film, particularly protein after wearing for a period of time. Lysozyme adsorption dynamics of fluorosilicone acrylate contact lenses has been studied in order to further improve data of protein adsorption, reduce adsorbing amount of surface protein, and prevent surface contamination of contact lenses.OBJECTIVE: To investigate the adsorption dynamics of fluorosilicone acrylate contact lenses to lysozyme in vitro. METHODS: A stock solution of lysozyme was prepared in Hanks balanced salt solution (2.0 g/L, solution Ⅰ) and different trifluoroacetic acid (TFA) concentrations were prepared. Recovery experiment, the contact lenses were placed in shaking incubator at 37 ℃ for varying time intervals. After incubation there was a single rinsing in Hanks balanced salt solution. Contact lenses in control group were placed in diluted water, and contact lenses in the other group were placed in different concentrations of TFA. For deposition, FSA contact lenses in experimental group were placed in shaking incubator at 37 ℃ for varying time intervals. After incubation there was a single rinsing in Hanks balanced salt solution. Then FSA contact lenses were immersed in 0.2% TFA solution. The amount of lysozyme was assayed with BCA method.RESULTS AND CONCLUSION: Lysozyme which attached to fluorosilicone acrylate contact lenses could be resolved by TFA, and the recovery was influenced by the immersed time and the concentration of TFA. The optimal time was 1 hour, and the optimum concentration was 0.2%. The adsorption dynamics of lysozyme on FSA contact lenses was a second-phased process, i.e., lysozyme adsorption increased rapidly during 10 minutes-1 hour, reached a plateau at 1 hour, stably adsorbed during 1-24 hours, and reached a saturation of 0.349 mg/cm~2. The recovery of lysozyme was lower at 10 and 30 minutes, but reached 90%-100% while the time of incubation was between 40 minutes and 24 hours.