Papers by Author: Nan Huang

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Authors: Feng Zhou, Liang Liang Wu, Yuan Yuan Cui, Ying Chen, Jie Yang, Nan Huang
Abstract: The experiments of artificial heart valves were divided into in vivo and in vitro experiments; in vivo experiments provide accurate experimental parameters serving in vitro research. Simulation experiment used in vitro usually goes like this, firstly design a similar model or prototype phenomenon, then analysis the model working out the regular parameters related to the process, ruled out the possibility of impact on the study of individual exist in vivo experiment. In vitro experiments are likely designed; performance can be simplified and prominently concerned about contents, even designed some extreme conditions to test. A number of means related to fluid experimental measurement are included, such as the Particle Image Velocimetry(PIV)[1], Dual Catheter Method [2],and ultrasonic method[3] and so on. However, these methods have different kinds of limitations, for example the Dual Catheter Method cannot be used as a routine determination for clinic due to its destructiveness, and PIV test requires expensive equipment. This study was designed by the image processing technology of high-speed photography aiming at the production of a reliable, simple, economic, injury-free and non-contact measurement method.
Authors: Zhi Hao Wang, Yong Xiang Leng, Nan Huang, Min Hao Zhu
Abstract: Titanium oxides films were deposited on tensile sample and vascular stents made of 316L stainless steel by unbalanced magnetron sputtering. The effects of structures, deposition temperature, Ti interlayer and thickness on the adhesion of titanium oxide films were investigated by tensile tests. The results revealed that the structure of the Ti-O films affect their adhesion dramatically. TiO film is brittle and fragile, lacking ability of deformation. Therefore its adhesion was worse than that of TiO2 film. The higher substrate temperature was helpful to improve adhesion of film, the adhesion of the TiO film deposited at 673K was better than those of the TiO films deposited at 323K and 473K. The adhesion of the TiO film with Ti interlayer was better than the one without interlayer. The introduction of Ti interlayer was beneficial to adhesion of film. The adhesion of thinner TiO2 film was better than that of thicker one. TiO2 film deposited on stents had good adhesion. After expansion, the film didn’t crack and peel off. TiO2 film has potential application on the vascular stents for improving its blood compatibility.
Authors: Jia Long Chen, Quan Li Li, Jun Ying Chen, Nan Huang
Abstract: This study deals with improving the cytocompatibility of titanium by a coating with heparin(hep), collagen(col) and CD34 antibody. Collagen and heparin molecules were adsorbed onto a titanium surface using a layer-by-layer (LBL) self-assembly technique. The col/hep coating were formed by alternating deposition of negatively charged heparin and positively charged collagen based on electrostatic interactions. Finally the CD34 antibody was absorbed onto the surface of col/hep coating by electrostatic interactions. The chemical composition and surface topography were investigated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The fluorescence microscopy images proved that the CD34 antibody was existed on the surface of the col/hep coating. The SEM results and the MTT test results showed that, compared to the surface of col/hep coating and the surface of titanium, the CD34 surface had better endothelial progenitor cells (EPCs) attachment and proliferation. The EPCs on the CD34 surface displayed the morphology of flat endothelium, and a confluent cell layer after cultured for 2d. This study suggested that this method maybe have good potential for surface modification of cardiovascular devices.
Authors: Jia Ju Tang, Jin Wang, Chang Jiang Pan, Ya Jun Weng, Nan Huang
Abstract: Three kinds of curcumin-loaded films (3wt%, 5wt%, 8wt%) were prepared using poly(lactic acid-co-glycol acid (PLGA) as the carrier of curcumin, and studied. The result of Fourier transform infrared spectroscopy (FTIR) and X-ray electron spectroscopy (XPS) show that the curcumin is dispersed in the PLGA films. High performance liquid chromatography (HPLC) analysis suggests that the release of curcumin can last 22-43 days. A fewer number of adhered and activated platelets are observed on the curcumin-loaded PLGA films. The activated partial thromboplastin time (APTT) increases for all curcumin-loaded films.
Authors: Guo Jiang Wan, Nan Huang, An Sha Zhao, Ping Yang, Paul K. Chu
Abstract: Ammonia implanted silicon was performed by using plasma immersion ion implantation (PIII) to form a silicon nitride films. Blood compatibility of the prepared samples was investigated by platelets adhesion testing. It showed less activation i.e. lower thrombosis risks occurs on the prepared silicon nitride films than control silicon sample. The enhanced blood compatibility of the material is attributed to the modified surface properties such as hydrophilicity from thermodynamic adsorption perspective, which is related to surface chemical bonding states achieved by PIII process.
Authors: Feng Juan Jing, Lu Wang, Y.W. Liu, J.Y. Cheng, Yong Xiang Leng, R.K.Y. Fu, X.B. Zhao, Paul K. Chu, Nan Huang
Abstract: Cerium oxide films have been fabricated using dual plasma deposition. X-ray diffraction. (XRD) reveals a crystalline phase and X-ray photoelectron spectroscopy (XPS) shows that La exists predominantly in the +4 oxidation state. The activated partial thromboplastin time is longer than that of blood plasma and stainless steel. Furthermore, the numbers of adhered, aggregated and morphologically changed platelets are reduced compared to low-temperature isotropic carbon (LTIC). HUVEC cells exhibit good adhesion and proliferation behavior on cerium oxide films. This study suggests rare earth oxide films are potential blood-contacting biomedical materials.
Authors: Ling Ren, Jin Wang, Jia Ju Tang, Ch.J. Pang, M. Maitz, Nan Huang
Abstract: Sirolimus-loaded poly (lactic acid-co-glycol acid) (PLGA) films were prepared by a casting method. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to determine the optimal concentration of sirolimus for vascular smooth muscle cell (VSMC) inhibition effect. Based on the results of MTT, three samples of different weight percent loaded-sirolimus (2wt%, 6wt%, 15wt%) PLGA films were selected. The release of lactate dehydrogenase (LDH) was used to evaluate the immediate toxicity of the sirolimus-loaded PLGA films and it was shown that the three different concentrations of sirolimus-loaded films have low toxicity. Alamar blue results indicate that the sirolimus-loaded films have better antiproliferation effect than 316 stainless steel (SS). The higher the sirolimus concentration in the film is, the better is the antiproliferation effect. These films may be used for stent coating to inhibit in-stent restenosis induced by VSMC proliferation.
Authors: Quan Li Li, Nan Huang, Zhi Qing Chen, Xu Yan Tang
Abstract: Phosphorylated chitosan (PCS) was used as the template to control hydroxyapatite(HAp) growth, a novel nanocomposite composed of PCS and HAp was synthesized by biomimetic method. Calcium phosphate (Ca 2+= 60mM, Ca/P = 1.67) solution in HCl was added dropwise into PCS solution in NaOH. The precipitate was lyophilized to obtain the composite. The biocompatibility of the PCS-HAp nanocomopite was evaluated by osteoblast culture in vitro. The results showed that low crystallized HAp nanocrystals was formed on the PCS fibers and its crystallographic c-axis were aligned preferentially parallel to the long axis direction of PCS; the composite have good biocompatibility in vitro. It is expected that the novel composite to be a potential material for bone repair.
Authors: Jin Wang, P. Li, H. Sun, Ping Yang, Y.X. Leng, Ji Yong Chen, Nan Huang
Abstract: We report a study involving chitosan chains immobilized on poly (ethylene terephthalate) (PET) films by plasma and ultraviolet (UV) grafting modification. The surface structure of the modified PET is determined by means of attenuated total reflection Fourier transform infraed spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS). The results show that the chains of chitosan are successfully grafted on the surface of PET. Platelet adhesion evaluation in vitro is conducted to examine the blood compatibility in vitro. Scanning electron microscopy (SEM) and optical microscopy reveal that the amounts of adhered, aggregated and morphologically changed platelets are reduced on the chitosan-immobilized PET films. The number of platelet adhered on the modified film is reduced by almost 48% compared to the amount of platelets on the untreated film. Our result thus shows that chitosan immobilized on the PET surface improves blood compatibility.
Authors: Y. Xu, Nan Huang, Hong Sun
Abstract: In this work, nonstoicheometric titanium oxide film on silicon matrix was prepared by unbalanced reactive pulsed magnetron sputtering /hydrogen plasma reduction method. The film chemical composition was analyzed by X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The XRD patterns of the prepared films showed that titanium oxide films possess the single phase rutile structure . the XPS spectra of the film displayed that the valence state of Ti is Ti4+, Ti3+ and Ti2+ respectively and the films were nonstoichiomeric Ti-O film. The evidence showed that isolated oxygen exist in films. Ti/O ratio of Ti-O film from the XPS data vary with depth under different reduction temperature and time. And it corresponded with platelet adhesion tests of Ti-O film in vitro. Antithrombotic property of reduced titanium oxide thin films was examined by platelet adhesion tests. The results showed that the Ti-O films with lower non-stoicheometrical extent posses the better anticoagulation property than stoichiomeric TiO2 film and the Ti-O films with higher non-stoicheometrical extent. Hence hydrogen introducing is an effective way to improve the bloodcompatibility of titanium oxide film.
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