Construction of ultrasmooth PTFE membrane for preventing bacterial adhesion and cholestasis.

Bacterial adhesion and bile sludge accumulation can increase the risk of complications such as stent restenosis after biliary stent implantation. Compared with active and passive antimicrobial surfaces, a significant advantage of slippery liquid-infused porous surfaces (SLIPSs) is their recoverable anti-adhesive properties. According to the mechanism of SLIPSs and the application environments of the biliary system, a polytetrafluoroethylene (PTFE) electrospun fibrous membrane-impregnated silicone-oil system was developed to construct an ultrasmooth surface. Experimental results indicated that a PTFE SLIPS with 350 cSt of silicone oil had an extremely small roll angle (< 5°) and a high slip rate (4.8 ± 0.1 mm/s) and maintained excellent sliding stability after 7 d of immersion in model bile system. Thus, it can inhibit the adhesion of proteins, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, and bile sludge. Moreover, when human fibroblasts were cultured on the PTFE SLIPS, it exhibited good cytocompatibility. Therefore, the proposed ultrasmooth PTFE membranes provide a promising alternative for biliary system to prevent bacterial adhesion and bile sludge accumulation.

An enhanced periosteum structure/function dual mimicking membrane forin-siturestorations of periosteum and bone.

Periosteum plays a pivotal role in bone formation and reconstruction. The ideal repair process for critical-size bone defects with periosteum damage is to induce regeneration of periosteum tissue and the subsequent bone regeneration derived by the periosteum. Inspired by the bilayer structure of the natural periosteum, we develop a periosteum structure/function dual mimicking membrane for thein-siturestoration of periosteum and bone tissue. Among them, the macroporous fluffy guiding layer (TPF) simulates the fibrous layer of the natural periosteum, which is conducive to infiltration and oriented growth of fibroblasts. And the extracellular matrix-like bioactive layer (TN) simulates the cambium layer of the natural periosteum, which significantly enhances the proliferation and osteogenic differentiation of rat bone marrow mesenchymal stem cells. A middle dense layer (PC) connects the above two layers and has the function of preventing the invasion of soft tissues while enhancing the biomimetic periosteum.In vivorestoration results show that the tri-layer biomimetic periosteum (TPF/PC/TN) has an outstanding effect in promoting the regeneration of both vascularized periosteum and bone at the same time. Therefore, the enhanced biomimetic periosteum developed in this research has a great clinical value in the efficient and high-quality reconstruction of critical-size bone defects with periosteum damage.

Research Progress of Antibacterial Biliary Stent / 中国医疗器械杂志

Biliary stent has been widely used in the treatment of biliary stricture and obstruction, it can relieve the pain of patients effectively, but bacterial infection and stent obstruction are still troublesome after surgery. We introduce the mechanism of infection and stent blockage caused by bacterial invasion after biliary stent implantation, and expound the formation mechanism of bacterial biofilm and bile sludge in this review. Antibacterial biliary stent is an effective way to inhibit biliary tract infection, the literatures on antibacterial modification of biliary stent with different antibacterial methods in domestic and abroad are reviewed, and the research prospect of antibacterial biliary stent is summarized and prospected.

Influence of PEG on heparin release of heparin-loading PCL/PEG vascular prosthesis membranes / 国际生物医学工程杂志

Objective To investigate the influence of polyethylene glycol (PEG) on heparin release of heparinloaded polycaprolactone/polyethylene glycol (PCL/PEG) membranes used in artificial vascular peosthesis.Methods Heparin-loaded PCL/PEG membrane samples with different PEG mass contents of 0,0.5％,10％ and 15％ were prepared by blending method and freeze-drying technology.The influence of PEG on heparin release was experimental studied in vitro.The influence of PEG on the structural characteristics of the samples were investigated by X-ray diffraction,Fourier transform infrared spectrum and differential scanning calorimeter.Results The addition of PEG reduced the heparin release resistance.The results showed that the average release rate of heparin in the first day and the release amount for 34 d were improved.Both these parameters increased with the increase of PEG mass content.The X-ray diffraction,Fourier transform infrared spectroscopy and differential scanning calorimetry showed that the crystallinity of PCL membrane was slightly enhanced by the addition of heparin,but the overall effect was not significant.In addition,the addition of heparin could promote the crystalline grain growth of PEG,and a common distribution of heparin and PEG in the matrix was observed.Conclusions The heparin release control can be achieved by adjusting the PEG mass content in heparin-loading PCL/PEG membranes prepared by blending method and freeze-drying technology.The proposed samples may have anticoagulant effect,which can be expected to be used as small-diameter artificial vascular prosthesis material.

Detection of blocking antibodies in sera of RSA / 中国免疫学杂志

Recurent spontaneous abortion (RSA) was classified into the primary (1?) and the sec-ondary (2?) according to patients histoty.Occurence of blocking antibodies between them wasinvestigated with mixed lymphocyte reaction—blocking assay and complement dependent cyto-toxicity assay.It was found that the primary abortion had been mainly caused by lack of block-ing antibodies,the secondary abortion without lack of blocking antibodies.Thus,the primaryabortion is different from the secondary abortion in aspects of immune aetiology and immunemechanisms although their clinical manifestations are similar.