Medical polyurethane fiber membrane after extraction with water, and then establish the determination of N, N dimethyl acetamide (DMAC) in Medical polyurethane fiber membrane by GC, and discuss the analysis and evaluation of other extracts of polyurethane fiber membrane for the determination of DMAC in the linear range of the average recovery rate was more than 90%, the RSD 1.51%-2.08% (n = 6). This method is simple, fast, sensitive and accurate, and may serve as a mass control method for DMAC in Medical polyurethane fiber membrane.
Acetamides ; chemistry ; Chromatography, Gas ; Membranes, Artificial ; Polyurethanes ; chemistry ; Water

Gastrointestinal (GI) cancers cause obstruction of the GI tract including biliary tree. In advanced GI cancer, endoscopic stent insertion is the treatment of choice. However, the current stent allows only mechanical palliation of obstructed GI tract and has no anti-tumor effect. The primary role of a drug eluting stent (DES) in gastrointestinal malignancy is that it decreases the tumor re-growth and sustains the stent patency. This might not be as impressive as the effect of a vascular DES which decreases the incidence of restenosis and thus increases the survival rate of the patient. However, in terms of improving the quality of life of the patient, maintaining the stent patency is one of the most important task of GI doctors. With an advanced technology in stent production, Korea would be able to play an active role in the field of DES especially with more advanced anti-tumor effect. Moreover, advances in this type of drug delivery system will enable the development of local treatment of GI malignancy using endoscopy.
*Drug-Eluting Stents ; Gastrointestinal Diseases/*drug therapy ; Humans ; Polyurethanes/*chemistry

A novel Cu-IUDs material, PU/PEG/Cu nanocomposite, was prepared by melt blending method with thermoplastic polyurethane (PU) as the matrix, with polyethylene glycol (PEG) as a hydrophilic modifier, and with nanometer particles of copper as active matter instead of copper wire or copper tube. The structure, morphology, mechanical properties, thermal stability and water absorption were investigated by using FT-IR, XRD, SEM and so on. The results indicated that the nanometer particles of copper were uniformly dispersed in the matrix in PU/PEG/ Cu nanocomposites. It can be seen that the water absorption ability of this nanocomposite was obviously improved while mechanical properties and thermal stability were at high levels. These results provided a good basis for the studies on the cupric ions release of the nanocomposites in future.
Biocompatible Materials ; chemistry ; Intrauterine Devices, Copper ; Nanocomposites ; chemistry ; Polyethylene Glycols ; chemistry ; Polyurethanes ; chemistry

Acrylic Resins ; chemistry ; Composite Resins ; chemistry ; Dental Research ; Dental Stress Analysis ; Polymerization ; Polyurethanes ; chemistry

The progress of research of the physical and chemical modification methods to improve the antithrombogenic property of biomedical polyurethane (PU) in the past five years is reviewed in this paper. The physical modification method includes physical blending, physical vapor deposition (PVD) and replication molding technique. Meanwhile, chemical modification method is focused on the covalent bonding to immobilized special molecular. Moreover, the covalent bonding method covered functionalizing the PU surface with tailor-made groups in the bulk and the activation of the surface to form unstable active sites for further reactions.
Animals ; Biocompatible Materials ; chemistry ; pharmacology ; Chemical Phenomena ; Fibrinolytic Agents ; chemistry ; pharmacology ; Humans ; Polyurethanes ; chemistry ; pharmacology

A series of bio-based thermosetting polyurethanes (Bio-PUs) were synthesized by the crosslinking reaction of polylactide and its copolymers diols with hexamethylene diisocyanate (HDI) trimer. The obtained Bio-PUs were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Thermal Gravimetric Analysis (TGA), universal tensile testing machine and cytotoxicity test. Results indicate that the PLA copolymer (P(LA-co-CL)) diols reduced the glass transition temperature (Tg) of Bio-PUs and improved their thermal stability, compared with PLA diols. The Bio-PUs synthesized from P (LA-co-CL) diols exhibit better mechanical performance and shape memory properties. Especially, Young modulus and elongation at break of the obtained Bio-PUs were 277.7 MPa and 230% respectively; the shape recovery time of the obtained Bio-PUs at body temperature was only 93 s. Furthermore, alamar blue assay results showed that the obtained Bio-PUs had no cell toxicity.
Biocompatible Materials ; chemistry ; Materials Testing ; Polyesters ; chemistry ; Polymers ; Polyurethanes ; chemistry ; Spectroscopy, Fourier Transform Infrared ; Temperature

BACKGROUNDPeople recently realized that it is important for artificial vascular biodegradable graft to bionically mimic the functions of the native vessel. In order to overcome the high risk of thrombosis and keep the patency in the clinical small-diameter vascular graft (SDVG) transplantation, a double-layer bionic scaffold, which can offer anticoagulation and mechanical strength simultaneously, was designed and fabricated via electrospinning technique.

METHODSHeparin-conjugated polycaprolactone (hPCL) and polyurethane (PU)-collagen type I composite was used as the inner and outer layers, respectively. The porosity and the burst pressure of SDVG were evaluated. Its biocompatibility was demonstrated by the 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyl-2H tetrazolium bromide (MTT) test in vitro and subcutaneous implants in vivo respectively. The grafts of diameter 2.5 mm and length 4.0 cm were implanted to replace the femoral artery in Beagle dog model. Then, angiography was performed in the Beagle dogs to investigate the patency and aneurysm of grafts at 2, 4, and 8 weeks post-transplantation. After angiography, the patent grafts were explanted for histological analysis.

RESULTSThe double-layer bionic SDVG meet the clinical mechanical demand. Its good biocompatibility was proven by cytotoxicity experiment (the cell's relative growth rates (RGR) of PU-collagen outer layer were 102.8%, 109.2% and 103.5%, while the RGR of hPCL inner layer were 99.0%, 100.0% and 98.0%, on days 1, 3, and 5, respectively) and the subdermal implants experiment in the Beagle dog. Arteriography showed that all the implanted SDVGs were patent without any aneurismal dilatation or obvious anastomotic stenosis at the 2nd, 4th, and 8th week after the operation, except one SDVG that failed at the 2nd week. Histological analysis and SEM showed that the inner layer was covered by new endothelial-like cells.

CONCLUSIONThe double-layer bionic SDVG is a promising candidate as a replacement of native small-diameter vascular graft.

Animals ; Bionics ; Blood Vessel Prosthesis ; Cell Line ; Collagen ; Dogs ; Heparin ; chemistry ; Mice ; Polyesters ; chemistry ; Polyurethanes ; chemistry

Polyurethanes are popularly used in cardiovascular and other biomedical fields due to their good biocompatibility as well as mechanical properties. But they are subject to biodegradation in vivo for a long time, and cause inflammation, so improving the biocompatibility of medical polyurethanes is an important subject of biomaterials. Recent researches have focused on biological modelling of biomaterials for improving the biocompatibility of polyurethanes. This paper reviews two main methods for improving biocompatibility of polyurethanes-endothelial cells seeding and mimic biomembrane (phospholipid surface), and summarizes the main procedures and questions of these two methods.
Biocompatible Materials ; chemistry ; Endothelial Cells ; drug effects ; Humans ; Phospholipids ; chemistry ; Polyurethanes ; chemistry

In order to improve the interfacial bonding strength of hydroxyapatite/polyurethane implanted material and dispersion of hydroxyapatite in the polyurethane matrix, we in the present study synthesized nano-hydroxyapatite/polyurethane composites by in situ polymerization. We then characterized and analyzed the fracture morphology, thermal stability, glass transition temperature and mechanical properties. We seeded MG63 cells on composites to evaluate the cytocompatibility of the composites. In situ polymerization could improve the interfacial bonding strength, ameliorate dispersion of hydroxyapatite in the properties of the composites. After adding 20 wt% hydroxyapatite into the polyurethane, the thermal stability was improved and the glass transition temperatures were increased. The tensile strength and maximum elongation were 6.83 MPa and 861.17%, respectively. Compared with those of pure polyurethane the tensile strength and maximum elongation increased by 236.45% and 143.30%, respectively. The composites were helpful for cell adhesion and proliferation in cultivation.
Biocompatible Materials ; chemistry ; Cell Adhesion ; Cell Line ; Durapatite ; chemistry ; Humans ; Polymerization ; Polyurethanes ; Tensile Strength ; Transition Temperature

It has been well known that fluorinated polyurethanes exhibit unique low surface energy, biocompatibility, biostability and nonsticking behavior. Consequently, these polymers have attracted considerable interest. In this study, the effect of various concentrations of fluorinated polyurethanes in the polyurethanes on the surface structures of the blends and their hemocompatibility were investigated by XPS, AFM, contact angle and platelet adhesion. It was found that the high concentration fluorine on the outer surfaces of the blends obtained with the low concentration of fluorinated polyurethanes (F: 0.342 wt%) in the blends was the same as that of the fluorinated poly(ether urethane)s, and all of the blends and the fluorinated poly(ether urethane)s had good hemocompatibility, compared with poly(ether urethane)s. The polymer blends and fluorinated poly(ether urethane)s suppressed platelet adhesion due to their high hydrophobicity and low surface tension. The XPS, AMF and contact angle results indicated that the high hydrophobicity of outer surface of the polyurethane blends is independent of the fluorinated polyurethanes content in the polymer blends but related to the concentration of the CF3 groups because the lower critical surface tensions and higher contact angle of many fluorinated surfaces reflect the concentration of CF3 groups.
Coated Materials, Biocompatible ; chemistry ; Ethers ; Fluorine ; Humans ; Platelet Adhesiveness ; Polyurethanes ; chemistry ; pharmacology ; Prostheses and Implants ; Surface Properties