Research on fibrinogen adsorption and its transformation response in hemocompatibility / 生物医学工程学杂志

In this research,enzyme linked immunoassay (ELISA) was used to assay the fibrinogen (FIG) adsorbed on the Ti-O films and on the low temperature isotropic carbon (LTIC) films which were planted in the femoral arteries of 6 mongrel dogs for six months, respectively. The Ti-O films were planted in the dogs' left femoral arteries; the LTIC films as controls were planted in the dogs' right femoral arteries. The contents adsorbed in these two kinds of films were examined by scanning electron microscopy (SEM). The quantities of FIG adhered or denatured on the Ti-O films or LTIC films determined by ELISA, and the platelets adhered on the two kinds of films examined by SEM were of significant difference between the two groups. In the blood vessel, the amount of FIG adhered on biomaterial was related to its component and construction. FIG released electron to the biomaterial and induced the unfolding of C term of the gamma-chain of FIG, and the conjugation point and effect point were exposed. In conclusion, the biomaterial, which has the capability for resisting the electron release from FIG as well as for maintaining the invariable electric condition, will have excellent hemocompatibility.

An experimental study on the cytokine expression of macrophage influenced by biomaterials / 生物医学工程学杂志

This experiment was designed to investigate the influence of two biomaterials, titanium oxide (Ti-O) and stainless steel (SS), on the cytokine expression of macrophage, and further, to evaluate their biocompatibility. After being co-cultured with Ti-O and SS for 72 h, the cell number and morphology of macrophages attached on materials were detected by fluorescent microscope and SEM. Nitride oxide (NO) and monocyte chemoattractant protein 1 (MCP-1) released by the macrophages co-cultured with different materials were also examined and compared. We found that the cell number of macrophages attached to Ti-O was smaller than that attached to SS. The levels of NO and MCP-1 released by the macrophages co-cultured with Ti-O were lower when compared with those released by macrophages co-cultured with SS. These results demonstrate that Ti-O has better biocompatibility than does SS.

Anti-restenosis study on a new drug eluting stent / 生物医学工程学杂志

The objective of this experimental study was to assess the effects of a new kind of drug eluting coronary stent. Fourteen mini-pigs were used; seven normal stainless stents and seven new drug eluting stents were implanted in their normal coronary arteries, respectively. Angiography was performed and followed by pressure-fixation of the coronary arteries for light and electron microscopic examinations at the end of three months after implantation. Repeated angiography showed that all the stented coronary segments were open. With no additional antithrombotic treatment, there was no thrombus formed in the stented coronary segments. Scanning electron microscopy analysis showed the implanted stent surface was covered by endomembrane without thrombus formation. The endothelial cell in the membrane was clear and lined by the direction of blood flow. Histomorphological analysis revealed the neointima in normal stainless stent group was thicker than that in new drug eluting stent group, and the neointima was composed of smooth muscle cell and extracellular matrix. The result of this study shows that this kind of stent could reduce the rate of the re-stenosis and occlusion of PTCA. This stent can be used in clinical trials.

Effects of Stainless Steel and Titanium Oxide in Stimulation of Endothelial Cells Releasing NO and MCP-1 / 现代生物医学进展

To investigate the influence of stainless steel(SS)and titanium oxide(Ti-O)thin films on the cytokine released by en-dothelial cells.Ti-O films were prepared by unbalanced magnetron sputtering deposition system(UBMS).Human umbilical vein en-dothelial cells(HUVECS)were isolated and seeded on SS and Ti-O materials.Nitride oxide (NO)and monocytc chemotactic protein one(MCP-1)concentrations were determined in the supematants with enzyme linked immunosorbent assay(ELISA)at 1,3 and 5 days after culture,and the morphology of the cells was observed using scanning electron microscopy(SEM).The results showed that the similar amount of HUVECs was presented in SS and Ti-O culture.But HUVEC had better morphology on Ti-O film than SS.The NO and MCP.1 test also showed that HUVECs on Ti-O film had a better bio-function than SS.It is concluded that Ti-O film as a biomaterial may have a better endothlieal compatibility,which can be used to enhance the endothelialization.

Study on a novel vascular stent material (titanium oxide, Ti-O) coated with albumin and heparin: is it hemocompatible with fibrinogen / 生物医学工程学杂志

The functional hemocompatibility between fibrinogen (FIG) and a novel vascular stent material (Ti-O film fixed with albumin and heparin) was investigated as follows: (1) Preparing the new biologic material (Ti-O) film; (2) Coating albumin and heparin on the Ti-O film; (3) Testing platelets (PL) adsorption; (4) Determining FIG adhesion number by use of enzyme linked immunoassay (ELISA); (5) Implanting the films from the test group of Ti-O film and from the comparison group of stainless steel (SS) film into the left and right femoral arteries respectively in 4 dogs. It was proved that albumin and heparin were fixed on Ti-O film. After 6 months, the femoral arteries of the dogs were resected. In the test group of Ti-O film coated with albumin and heparin, few PL adhered to the coat, their form did not change, and no thrombus was found by scanning electron microscopy; the result was better than that of plain Ti-O film, and was much better than that of SS film. Ti-O maintained normal transformation condition of FIG, and no C terminal of gamma chain in FIG was revealed. As it is known whether the hemocompatibility of a biomaterial is good depends upon its adsorption of FIG, and Ti-O has excellent reaction on albumin and heparin by chemical processes. In this study, the Ti-O film coated with albumin and heparin further reduced the absorption of FIG and PL when compared against the plain Ti-O film. So the Ti-O film coated with albumin and heparin has the insistent and permanent anticoagulant character.