Electrochemical polishing of 316L stainless steel stent / 中国组织工程研究

Using direct current-electropolishing technique, the present study investigated the function of components and effects of operating conditions on polishing quality direct current-electropolishing of 316L stainless steel stent materials. Smooth surface was obtained quickly using this technique.

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.

The effect of surface free energy parameters of diamond-like carbon films deposited on medical polyethylene terephthalate on bacterial adhesion / 生物医学工程学杂志

Diamond-like carbon (DLC) films were deposited by acetylene plasma immersion ion implantation-deposition (PIII-D) on biomedical polyethylene terephthalate (PET). The capacities of Staphylococcus aureus (SA), Staphylococcus epidermidis (SE), Escherichia coli (EC), Pseudomonas aeruginosa (PA) and Candida albicans (CA) for adhesion to PETs are quantitatively determined by the plate counting and Gamma-ray counting of 125I radio labeled bacteria in vitro. The results indicate that the capacities of five types of bacteria for adhesion to PETs are all suppressed by C2H2 PIII-D (P<0.05). The surface energy components of the various substrates and bacteria are calculated based on measurements in water, formamide and diiodomethane and Lifshitz-van del Waals/acid-base approach (LW-AB). The surface free energies obtained are used to calculate the interfacial free energies of adhesion (deltaF(adh)) of five kinds of bacteria on various substrates, and the results show that it is energetically unfavorable for bacterial adhesion to the DLC films already deposited on PET by C2H2 PIII-D.

Research of plasma adsorption and action of platelet adhesion of Dacron modified by plasma surface modification / 生物医学工程学杂志

In this paper, polyethylene glycol (PEG) of different molecular weight was grafted on the polyethylene terephthalate (PET, Dacron) films by plasma surface grafting modification. The competitive adsorption relation of plasma (fibrinogen and albumin) adsorbing on materials surface was analyzed in light of surface energy and interface free energy. The results indicated that the PET films grafted PEG long chain molecular possesses the characteristic of preferentially adsorbing albumin and this adsorption tendency of grafted PEG6000 sample is most distinct. The platelet adhesion tests of the PET films whose surfaces were pre-set in contact with fibrinogen and albumin indicated that the surface adsorbing albumin can distinctly inhibit platelet adhesion and aggregation and possess favorable blood compatibility, but the surface adsorbing fibrinogen can enhance platelet adhesion and aggregation.