Cu-bearing stainless steel has been found to have obvious inhibition performance against encrustation in vitro. This study was aiming to further investigate the inhibitory effect of a Cu-bearing stainless steel（316 L-Cu SS） on the infectious encrustation based on its antimicrobial activity. The encrustation in presence of bacteria, antibacterial performance, urease production and Ca and Mg precipitation were examined by scanning electron microscopy, antibacterial assay, enzyme-linked immunosorbent assay and inductively coupled plasma-mass spectrometry, respectively. It was found that 316 L-Cu SS could inhibit the formation of bacterial biofilm due to the release of Cu^（2＋） ions and then decrease the urease amount splitting by bacteria, which produced a neutral environment with pH around 7. However, more encrustations coupled with bacterial biofilms on the surface of comparison stainless steel（316 L SS） with an alkaline environment were recorded. It can thus be seen that the 316 L-Cu SS highlights prominent superiority against encrustation in the presence of microorganisms.
Jing ZhaoLing RenBingchun ZhangZhiqiang CaoKe Yang
Implant-associated infection remains a difficult medical problem in orthopedic surgery. Therefore, the development of multifunctional bone implants for treating infection and regenerating lost bone tissue, which may be a result of infection, is important. In the present study, we report the fabrication of enoxacin- loaded poly （lactic-co-glycolic acid） （PLGA） coating on porous magnesium scaffold （Enox-PLGA-Mg） which combine the favorable properties of magnesium, the antibacterial property and the effect of inhibition of osteoclastic bone resorption of enoxacin. The drug loaded PLGA coating of Mg scaffold enables higher drug loading efficiency （52%-56%） than non-coating enoxacin loaded Mg scaffold （Enox-Mg） （4%-5%）. Enox- PLGA-Mg exhibits sustained drug release for more than 14 days, and this controlled release of enoxacin signifcantly inhibits bacterial adhesion and prevented biofilm formation by Staphylococcus epidermidis （ATCC35984） and Staphylococcus aureus （ATCC25923）. Biocompatibility tests with Balb/c mouse embryo fibroblasts （Balb/c 3T3 cells） indicate that PLGA-Mg has better biocompatibility than Mg. Finally, we also demonstrate that Enox-PLCA-Mg extract potently inhibited osteoclast formation in vitro. Therefore, Enox- PLCA-Mg has the potential to be used as a multifunctional controlled drug delivery system bone scaffolds to prevent and/or treat orthopedic peri-implant infections.
Yang LiXuqiang LiuLili TanLing RenPeng WanYongqiang HaoXinhua QuKe YangKerong Dai
In this work, porous Ti6Al4V alloys with 30%-70% porosity for biomedical applications were fabricated by diffusion bonding of alloy meshes. Pore structure was characterized by Micro-CT and SEM. Compressive behavior in the out-of-plane direction and biocompatibility with cortical bone were studied. The results reveal that the fabricated porous Ti6Al4V alloys possess anisotropic structure with square pores in the in-plane direction and elongated pores in the out-of-plane direction. The average pore size of porous Ti6Al4V alloys with 30%-70% porosity is in the range of 240-360 Bin. By tailoring diffusion bonding temperature, aspect ratio of alloy meshes and porosity, porous Ti6Al4V alloys with different compressive properties can be obtained, for instance, Young＇s modulus and yield stress in the ranges of 4-40 GPa and 70-500 MPa, respectively. Yield stress of porous Ti6Al4V alloys fabricated by diffusion bonding is close to that of alloys fabricated by rapid prototyping, hut higher than that of fabricated by powder sintering and space-holder method. Diffusion bonding temperature has some effects on the yield stress of porous Ti6Al4V alloys, but has a minor effect on the Young＇s modulus. The relationship between compressive properties and relative density conforms well to the Gibson-Ashby model. The Young＇s modulus is linear with the aspect ratio, while the yield stress is linear with the square of aspect ratio of alloy meshes. Porous Ti6Al4V alloys with 60%-70% porosity have potential for cortical bone implant applications.
It is not clear what effects of CD34-and CD133-specific antibody-coated stents have on reendothelialization and in-stent restenosis(ISR)at the early phase of vascular injury.This study aims at determining the capabilities of different coatings on stents(e.g.gelatin,anti-CD133 and anti-CD34 antibodies)to promote adhesion and proliferation of endothelial progenitor cells(EPCs).The in vitro study revealed that the adhesion force enabled the EPCs coated on glass slides to withstand flow-induced shear stress,so that allowing for the growth of the cells on the slides for 48 h.The in vivo experiment using a rabbit model in which the coated stents with different substrates were implanted showed that anti-CD34 and anti-CD133 antibody-coated stents markedly reduced the intima area and restenosis than bare mental stents(BMS)and gelatin-coated stents.Compared with the anti-CD34 antibody-coated stents,the time of cells adhesion was longer and earlier present in the anti-CD133 antibody-coated stents and anti-CD133 antibody-coated stents have superiority in re-endothelialization and inhibition of ISR.In conclusion,this study demonstrated that anti-CD133 antibody as a stent coating for capturing EPCs is better than anti-CD34 antibody in promoting endothelialization and reducing ISR.
