Study on the in vitro release behavior of bovine serum albumin from calcium phosphate coating on pure titanium surface / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the incorporation rate and release behavior of bovine serum albumin (BSA) incorporated into the calcium phosphate coating by biomimetic deposition, as well as the physical and chemical properties of the hybrid coating, and to provide experimental basis for the fabrication of growth factor/biomimetic calcium phosphate coating and exploration for the loading/release behavior of growth factors.</p><p><b>METHODS</b>Pure titanium specimens were immersed into saturated calcium phosphate solutions(SCP) containing no BSA (controlled group) and 3 different concentrations of BSA (experimental groups) : 1, 10 and 100 mg/L. Biomimetic calcium phosphate coating was formed on titanium surface and BSA was incorporated into the coating through co-deposition. The topography of the specimen was observed using scanning electron microscopy (SEM). Chemical structure and phase composition of coatings were detected by Fourier infrared spectroscopy (FTIR) analysis and X-ray diffraction (XRD) respectively. BSA incorporation rate and release profile were determined by bicinchoninic acid protein assay kit.</p><p><b>RESULTS</b>The biomimetic calcium phosphate coating was mainly composed of hydroxyapatite and octacalcium phosphate. BSA was successfully incorporated into the calcium phosphate coatings in all the 3 experimental groups. With the increase of BSA concentration, plate-like units of the coatings were turned into small grid structure. BSA incorporation rates of the three experimental groups were (72.4 ± 2.4)%, (62.3 ± 0.9)% and (42.2 ± 1.7)% respectively. The in vitro release test showed that all three BSA release profiles could be divided into two significant different stages: early burst release stage and later sustained release stage. The amount of BSA release of the 3 experimental groups in 24 h and 30 d were (1.57 ± 0.09), (8.82 ± 0.93), (140.24 ± 3.12) µg, and (2.39 ± 0.29), (14.39 ± 0.70), (151.06 ± 2.00) µg respectively.</p><p><b>CONCLUSIONS</b>Biomimetic calcium phosphate coating can be used as an effective carrier for protein. BSA concentration has an impact on the incorporation rate and release speed of BSA from the calcium phosphate coating. Favorable BSA incorporation rate and release behavior can be obtained at BSA concentration of 10 mg/L.</p>

Cell bioactivity of micro-arc oxidation coating on the surface of pure titanium / 中国组织工程研究

BACKGROUND:Micro-arc oxidation technique is used to modify the surface properties of titanium and titanium al oy. OBJECTIVE:To explore the surface properties of micro-arc oxidation film and its effect on the attachment, proliferation and alkaline phosphatase activity of MC3T3-E1. METHODS:Forty-six pure titanium discs, 10 mm in diameter and 2 mm in thickness, were randomly divided into two groups. The discs of the experimental groups were treated by micro-arc oxidation technique in an electrolytic solution containing 0.02 mol/L sodiumβ-glycerophosphate and 0.2 mol/L calcium acetate;while the discs of the control group was machine-polished. The surface appearance of the discs was observed by a scanning electron microscopy, the ratio of calcium to phosphorus on the coating surface was detected by X-ray spectroscopy, and the crystal ine phase composition of the coating was detected by X-ray diffraction analysis. cellular morphology in the process of attachment was observed under the scanning electron microscope. cellproliferation was determined by cellcounting kit-8 at 2, 4, 74 days, while alkaline phosphatase activity were determined at 7 and 14 days. RESULTS AND CONCLUSION:After micro-arc oxidation treatment, a rough and porous calcium-phosphate film was formed on the surface of titanium. The elements of micro-arc oxidation coating main mainly included Ca, P, O and Ti, and the micro-arc oxidation film was mainly composed of titanium oxide, calcium titanate, calcium phosphate and calcium metaphosphate. Under the scanning electron microscope, pseudopods appeared to grow out of the cells on the surface of micro-arc oxidation coating after 1 hour culture, and the typical morphology of the MC3T3-E1 cells could be observed at 4 hours. MC3T3-E1 proliferation (4 and 7 days of culture) and alkaline phosphatase activity (7 and 14 days of culture) were enhanced significantly in the micro-arc oxidation group compared with the control group. These findings indicate that the rough and porous calcium-phosphate coating produced by micro-arc oxidation technique on pure titanium surface could promote the early attachment, proliferation and osteogenic differentiation of MC3T3-E1.

Preparation of novel bioactive PCL bone tissue engineering scaffold / 生物医学工程学杂志

In the present study, porous PCL (poly (epsilon-caprolactone)) scaffolds were prepared through a melted extrusion manufacturing (MEM) machine, and carboxylate groups were formed on the surfaces of specimen by hydrolyzation with NaOH aqueous solutions. Apatite precursor was introduced on the surfaces of specimens with CaCl2 and K2 HPO4 under vacuum condition, and mineralization study was applied to these specimens. The results showed that the hydrophilicity of PCL surface was improved with the introduction of carboxylate groups, and the contact angle of surface was decreased to 26.52 degrees. A dense and uniform bone-like layer was confirmed to be formed on the surface of Ca-P treated specimens after mineralizing for less than 24 h in SBF by SEM and EDAX.