Advanced Biomaterials VI

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Authors: Jun Ying Chen, Yong Xiang Leng, Sh.N. Ge, Ping Yang, Jin Wang, H. Sun, Guo Jiang Wan, An Sha Zhao, Nan Huang
Abstract: In the work reported here, titanium oxide film were synthesized using magnetron sputtering from a high-purity Ti metal target while sustaining a differential oxygen partial pressure of from 0.02 to 0.30 Pa. The biological behavior of endothelial cells grown on the film surface was studied by in vitro human umbilical vein endothelial cell (HUVEC) culture investigation. Our studies revealed that the adherence, growth, and proliferation of endothelial cells on different Ti-O film surfaces were strongly affected by the oxygen partial pressure. The biocompatibility mechanisms of ECs on Ti-O film surfaces were explored using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), a-step profilometry, scanning electron microscopy (SEM), and atomic force microscopy (AFM). We conclude that the various film characteristics such as structure, composition and surface morphology due to the different oxygen partial pressures significantly influence the biological behavior of EC.
Authors: Hyun Joo Son, Dong Wook Han, H.H. Kim, Hee Joong Kim, In Seop Lee, Jeong Koo Kim, Jong Chul Park
Abstract: In this study, human dermal fibroblast behaviors onto non-porous PLGA (75:25) films immobilized with 1, 10 and 100 µg/ml collagen (CN) or fibronectin (FN) were investigated according to different cell-seeding densities (1,000, 10,000 and 100,000 cells/ml). Cell attachment and proliferation were assessed using water soluble tetrazolium salt. The results indicated that 1 µg/ml of FN-immobilized PLGA film demonstrated significantly (p < 0.05) superior cellular attachment to the intact PLGA film after 4 hr of incubation. Moreover, the number of attached cells was shown to be directly proportional to that of initially seeded cells. After 48 hr, the cells showed significantly (p < 0.05) higher proliferation onto 1 or 10 µg/ml of FN-immobilized PLGA films than onto other PLGA films, regardless of the initial cell-seeding density. In terms of CN-immobilization, cell proliferation was appreciably increased but it was relatively lower than FN-immobilization. These results suggested that ECM-immobilization can enhance the cell affinity of hydrophobic scaffolds and be used to potential applications for tissue engineering by supporting cell growth.
Authors: Nan Huang, Ping Yang, Yong Xiang Leng, Jin Wang, Jun Ying Chen, H. Sun, Guo Jiang Wan, An Sha Zhao, Pei Dao Ding
Abstract: In the present paper, the scientific basis, technique approaches, the present status and the development trends of surface modification for blood contacting materials are discussed briefly. The work in authors’ Lab. is also presented.
Authors: Lan Xin Xu, Yong Xiang Leng, Hong Fang Zhou, Y.W. Liu, Nan Huang
Abstract: Titanium oxide films were prepared by reactive magnetron sputtering using continuous or pulsed DC sputtering power. The results of the structure and vitro hemocompatibility analyses indicated that non-stoichiometric titanium oxide films possess better hemocompatibility than LTIC and that the hemocompatibility of the titanium oxide films are evidently improved with the increase of rutile phase. This can result from the lower interface tension between titanium oxide films and biological substances and lower ratio of dispersive and polar component of the surface energy.
Authors: Feng Juan Jing, Nan Huang, Jun Ying Chen, Yong Xiang Leng, H. Sun
Abstract: Aminopropyltriethoxysilane (APTE) was covalently interacted with hydroxyl on the surface of Ti-O films prepared by magnetron sputtering, and albumin and heparin were immobilized on the APTE-coated surface with addition of 1-ethyl-3- (3-dimethyl aminopropyl) carbodiimide (EDC) as cross-link agent. X-ray photoelectron spectroscopy (XPS) was used to investigate the modified surface. Contact angle results indicate that there was an increase in the contact angle to the surface of APTE-coated Ti-O films, and a decrease in the contact angle to the surface of albuminand heparin-immobilized surfaces. Blood platelet adhesion in vitro was improved significantly after immobilization of albumin and heparin on Ti-O films. Endothelial cell (EC) culture tests showed that EC could grow on the surface of Ti-O films immobilized with albumin and heparin, but the growth and proliferation behavior of endothelial cells was not as good as on naked Ti-O films. This investigation showed that the surface of bio-inert inorganic materials immobilized with biological molecules is feasible and effective for improving the blood compatibility.
Authors: In Seop Lee, J.M. Park, Hyun Joo Son, Jong Chul Park, Geun Hee Lee, Y.H. Lee, Fu Zhai Cui
Abstract: Implantable neural prostheses form hybrid interfaces with biological constructs, and the application of electrical fields can restore functions of patients with neurological damages. The various stoichiometric compositions of iridium oxide were synthesized using reactive magnetron sputtering. The charge injection behavior of iridium oxide deposited with an O2/Ar ratio of 0.5 was similar to pure Ir. The charge density of iridium oxide increased with increasing O2/Ar ratio, and increasing thickness of iridium oxide.
Authors: Yong Xiang Leng, Ping Yang, Ji Yong Chen, Lan Xin Xu, An Sha Zhao, H. Sun, Jin Wang, Nan Huang
Abstract: Surface modification has shown great potential for improving the hemocompatibility of biomedical materials and devices. In this paper we describe our work on improving blood compatibility with Ti–O thin films prepared by unbalanced DC magnetron sputtering. The structure and surface chemical and physical properties of the films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), SEM, sheet resistance tests, and Hall effect measurements. The sheet resistance of the titanium oxide samples increased with oxygen pressure and shows a sharp increase when only TiO2 exists in the films. The band gap, carrier density and sheet resistance of the titanium oxide films synthesized at different oxygen pressure are different. These properties affect blood compatibility significantly. We suggest that the semiconducting nature of n-type Ti–O films with bandgap 3.0~3.2 eV, sheet resistance greater than 1 Ω.cm and carrier density of about 1.17 x 1016cm-2 leads to their excellent blood compatibility.
Authors: Quan Zeng, Zhi Qing Chen, Quan Li Li, Gang Li, Brian W. Darvell
Abstract: The improvement of the amount of OH functional groups and bioactivity of titanium metal was attempted by chemical treatment and subsequent hot water treatments. The surface morphology, chemical composition and crystal structure were used to characterize the Ti surfaces and their biocompatibility was evaluated by culturing with osteoblasts. Porous network bioactive anatase were prepared by immersion in the 5 M NaOH at 80ı for 24 h, followed by soaking in the water at 80ı for 48 h. The treatment with H2O2/HCl solution at 80ı for 30 min followed by hot water aging also produced an anatase titania gel layer. Percentage of surface OH groups was determined by XPS analysis. After chemical treatment and subsequent aging in hot water, the amount of surface OH groups increased. The modified Ti surface promoted the proliferation and the ALP activities of osteoblasts. These results indicate that the NaOH or H2O2/HCl treatment and subsequent hot water immersion improve the biocompatibility of Ti samples. On the other hand, a high OH group concentration is very important as functional groups for the apatite nucleation or biochemical modification via an organometallic interface of immobilizing biomolecules.
Authors: Wei Chang Xue, Chuan Xian Ding, Cong Cao, Yuqi Dong
Abstract: A new bioceramic coating based on diopside was prepared by plasma spraying. The surface and cross-section microstructure of the coating were examined by scanning electron microscopy. The thermal expansion coefficient of the diopside coating measured by a dilatometer adapted to that of titanium alloy. The bond strength of the coating was about 32.5 MPa, which is higher than that of HA coatings used in orthopedics and dentistry. The bioactivity of diopside coating was evaluated in vitro. After 15 days soaking in simulated body fluid, an apatite layer was formed on the surface of the coating. The cytocompatibility was investigated by studying the behaviour of human osteoblast cultured directly onto the surface of the coating. MTT assay was performed to assess the influence of the coating on cell proliferation. The morphologies of the cell were observed by SEM after incubation for 1 and 7 days. The results obtained indicated that plasma sprayed diopside coating may be a suitable candidate for bone and dental implant.
Authors: Feng Wen, Nan Huang, H. Sun, Ping Yang, Jin Wang
Abstract: Amorphous hydrogenated carbon (a-C:H) thin films were deposited on silicon wafers and Ti6Al4V substrate using plasma ion immersion implantation and deposition (PIII-D) at room temperature (R.T.). The composition and structure of a-C:H films were employed by X-ray photoelectron spectra (XPS) and Raman spectra. Nano-indenter tests measured the hardness of the films. In addition, wettability and bloodcompatibility were investigated. In this paper, the effects of hydrogen content on structure, mechanical properties, surface wettability and haemocompatibility were discussed.

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