Effect of ultraviolet rays on the re-activation of the physicochemical properties and bioactivity of aging titanium surface / 中国组织工程研究

BACKGROUND:The physicochemical properties and bioactivity of titanium surface will degrade with time because of the aging phenomenon,affecting the efficiency of implant-bone osseointegration.Therefore,the re-activation of the implant surface physicochencical properties and bioactivity is important.OBJECTIVE:To investigate the re-activation effect of ultraviolet rays on aging titanium surface.METHODS:Sand-blasted and acid-etched titanium discs were divided into three groups randomly:Group A was new titanium surface,Group B was stored in a sealed container for 4 weeks,Group C was treated with ultraviolet rays for 15 minutes after stored in the sealed container for 4 weeks.The surface roughness,elemental composition and surface energy of the titanium surface were examined by optical profilometer,X-ray photoelectron spectroscopy and contact angle measuring device,respectively.The bioactivity of the titanium surface was examined by cell culture experiments.MG63 osteoblast-like cells were cultured on the different titanium surfaces.After 30 minutes,1,2,4 hours of incubation,the cells were strained with Hoechst33342 fluorescence,and initial attachment of cells was evaluated by measuring the amount of cells attached to the titanium surface.The proliferation of cells was quantified in terms of cell density at 1 and 3 culture days using tetrazolium salt (MTS)-based colorimetry.RESULTS AND CONCLUSION:There was no obvious difference in the surface roughness of the three groups,and ultraviolet treatment did not change the surface morphology of titanium surface.X-ray photoelectron spectroscopy showed that the C element content of group A and group C was lower than that of group B (P ＜ 0.05),and the content of Ti,O,N elements was significantly higher than that of group B (P ＜ 0.05).No difference in the surface element composition between group A and group C was found.Both of the surface contact angles of group A and group C were Oo,but in group B,the value was 115°.The number of initially attached cells of group A and group C was significantly higher than that of group B after incubated 30 minutes,1,2 and 4 hours (P ＜ 0.05),and no difference between group A and group C was found.The proliferation of cells of group A and group C was significantly higher than that of group B after incubated 1 and 3 days (P ＜ 0.05),but no difference between group A and group C was found.In conclusion,ultraviolet rays show good effects on the re-activation of the aging titanium surface,which can reduce hydrocarbon contamination and recover the high surface energy to increase cell adhesion and proliferation.

Preparation and characterization of genipin-crosslinked silk fibroin/chitosan controlled-release microspheres / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the property of genipin-crosslinked silk fibroin(SF)/chitosan(CS) microspheres for slow releasing of bovine serum albumin (BSA).</p><p><b>METHODS</b>BSA-loaded genipin-crosslinked SF/CS microspheres were prepared by emulsion cross-linking technique. The micropheres were observed for surface morphology and size distribution under scanning electron microscope (SEM), and X-ray diffractometry (XRD) and fourier transform infrared spectroscopy (FTIR) were used to analyze their structural characteristics. BCA method was used for determining the drug entrapment, loading rate and cumulative drug release in 21 days.</p><p><b>RESULT</b>The microspheres were spherical and showed a smooth surface with an average diameter of 7.84∓0.97 µm. The drug entrapment efficiency of the microspheres was (50.16∓4.32)% with a drug loading ratio of (1.25∓0.11)% and a cumulative release of the total drug of (75.2∓2.53)% in 21 days.</p><p><b>CONCLUSION</b>Genipin-crosslinked SF/CS microspheres have a high drug entrapment efficiency and possess good capacity of sustained drug release.</p>

The influence of ultraviolet irradiation on sandblasted and acid-etching surface adsorbing human fibronectin / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To study the influence of ultraviolet (UV) irradiation on physical and chemical properties of sandblasted and acid-etched (SA) titanium surface and their ability to adsorb human fibronectin (HFn).</p><p><b>METHODS</b>SA and UV-SA surfaces were separately prepared. Surface morphology, roughness, elemental composition, wettability and HFn adsorption assay were performed for comparative analysis of these two surfaces.</p><p><b>RESULTS</b>SA and UV-SA surface had a similar morphology with multi-holes, and average roughness. UV-SA surface had a lower C content (22.83%) and higher O content (51.20%) and presented hydrophilicity, while SA surface showed hydrophobicity. But the quantity of adsorbed HFn on SA surface at 10 min assay point [(0.41 ± 0.07) µg] was statistically higher than that on UV-SA surface [(0.26 ± 0.08) µg](P = 0.007).</p><p><b>CONCLUSIONS</b>UV irradiation would not change the morphology and roughness of SA surface. However, it could reduce the hydrocarbon and increase the hydroxyl groups, and the absorption of HFn on UV-SA surface at 10 min assay point was statistically lower than that on SA surface. Therefore, the in-vitro bioactivity of UV-SA surface was not as good as that of SA surface.</p>