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- 저자 : Yakai Feng (검색결과 5 건)
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Heyun Wang,Yakai Feng,Zichen Fang,Ruofang Xiao,Wenjie Yuan,Musammir Khan 한국고분자학회 2013 Macromolecular Research Vol.21 No.8
In this paper, heparin was introduced into electrospun gelatin nanofibrous scaffold for assessment as a controlled delivery device in vascular tissue engineering application. Hybrid gelatin-heparin fibers with smooth surfaces and no bead defects were produced from gelatin solutions with 18% w/v in acetic acid aqueous solution. A significant decrease in fiber diameter was observed when the heparin content was increased from 1 to 5 wt%. The properties of composite gelatin-heparin scaffolds were confirmed by Fourier transform infrared spectroscopy (FTIR)and differential scanning calorimetry (DSC) measurement. The gelatin-heparin fibrous scaffolds were also cross-linked using 1 wt% glutaraldehyde vapor-phase for 7 days. A sustained release of heparin could be achieved from gelatinheparin scaffolds over 14 days. The results of the biocompatibility in vitro tests carried out using human umbilical vein endothelial cells indicated good cell viability and proliferation on the gelatin-heparin scaffolds. The results demonstrated that the use of electrospun gelatin fibers as heparin carriers could be promising for vascular tissue applications.
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Immobilized Bioactive Agents onto Polyurethane Surface with Heparin and Phosphorylcholine Group
Mingqi Tan,Yakai Feng,Heyun Wang,Li Zhang,Musammir Khan,Jintang Guo,Qingliang Chen,Jianshi Liu 한국고분자학회 2013 Macromolecular Research Vol.21 No.5
Heparin (HEP) and phosphorylcholine groups (PC) were grafted onto the polyurethane (PU) surface in order to improve biocompatibility and anticoagulant activity. After the surface grafting sites of PU were amplified with the primary amine groups of polyethylenimine (PEI), heparin was covalently linked onto the surface by the reaction between the amino group and the carboxyl group. PC groups were covalently immobilized on the PU-PEI surface through the reaction between the amino group and the aldehyde group of phosphorylcholine glyceraldehyde (PCGA). The surface density of primary amine groups was determined by a ninhydrin assay. The amino group density reached a maximum of 0.88 μmol/cm2 upon incorporation of 10 wt% PEI. The amount of heparin covalently immobilized on the PU-PEI surface was determined by the toluidine blue method. The grafting chemistry resulted in the comparatively dense immobilization of HEP (2.6 μg/cm2) and PC to the PU-PEI surfaces. The HEP and PC modified surfaces were characterized by water uptake (PU 0.15 mg/cm2, PU-PEI 3.54 mg/cm2, PU-HEP 2.04 mg/cm2, PU-PC 2.38 mg/cm2), water contact angle (PU 95.3º, PU-PEI 34.0º, PU-HEP 39.5º, PU-PC 37.2º), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS),atomic force microscopy (AFM), and scanning electron microscope (SEM). The results demonstrated that the PUPEI surface was successfully grafted with HEP and PC. The hydrophilicity and hemocompatibility of these grafted surfaces were significantly improved. These results suggested that the PU-HEP and PU-PC composite films are promising candidates for blood contacting tissue engineering.
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Jian Lu,Jintang Guo,Yakai Feng,Bin Gao 한국고분자학회 2012 Macromolecular Research Vol.20 No.7
An original phosphorylcholine (PC) containing vinyl monomer (compound 1) was grafted onto the surface of polycarbonate urethane (PCU) films by ultraviolet (UV) initiated polymerization. The vinyl monomer was synthesized from 2-hydroxyethyl methacrylate (HEMA), hexamethylene diisocyanate (HDI) and L-α-glycerylphosphorylcholine (GPC) by two relative reactions through the coupling of the isocyanate groups in HDI with the hydroxyl groups in HEMA and GPC, respectively. The existence of phosphorylcholine groups on the surface of compound 1-grafted PCU films was verified by X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and water contact angle measurements. The surfaces of the grafted PCU films showed lower water contact angles than did the surfaces of non-grafted PCU films. Furthermore, the surface morphology of a grafted PCU film was observed using scanning electrical microscopy (SEM), which showed that the grafted polymer film exhibits a rough and pinhole-free surface. In addition, the blood compatibility of the compound 1-grafted PCU films was evaluated by platelet adhesion studies using the non-grafted PCU film as a reference. It was found by SEM that fewer platelets adhered to the surfaces of the grafted PCU films compared to the reference. The high PC-grafted PCU film did not show any substantial platelet attachment on its surface. These results indicated that these compound 1-grafted polymers may have potential application as biomaterials for vascular grafts and some subcutaneously implanted devices.
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Wei Gao,Jintang Guo,Yakai Feng,Jian Lu,Musammir Khan 한국고분자학회 2012 Macromolecular Research Vol.20 No.10
Phosphorylcholine groups were covalently introduced onto a polycarbonateurethane (PCU) surface in order to create a biomimetic structure on the polymer surfaces. After introducing primary amine groups onto the polymer surface by 1,6-hexanediamine, phosphorylcholine groups were covalently linked onto the surface by the reductive amination between the amino group and the aldehyde group of phosphorylcholine glyceraldehyde (PCGA). The results of water contact angle test, X-ray photoelectron spectroscopy (XPS), and X-ray fluorescence spectrometer (XRF) analysis of the modified films indicated that PCGA had already been covalently linked to the PCU surface. The topographies and surface roughnesses were both imaged and measured by atomic force microscopy (AFM). Scanning electron microscopy (SEM)observation of the PCU films after treatment with platelet-rich plasma demonstrated that platelets had rarely adhered to the surface of the PCGA-grafted PCU films but had mainly adhered to the surface of the blank PCU films. The platelet adhesion result indicated that the PC modified PCU films could resist platelet adhesion after grafting with PCGA, and that these PCGA-grafted PCU materials, potentially, might be applied as blood-contacting materials.
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