摘要:

The effect of exposure time of thin films of soluble collagen to glutaraldehyde (GTA) vapour was studied at 37°C, and was evaluated by examining the thermal and biological stability and the swelling ratio. It was found that the collagen films treated with GTA vapour for 18 h showed the highest denaturation temperature, the lowest swelling ratio, and an enhanced proteolytic stability. This study shows that soluble collagen can be effectively cross-linked with GTA vapour and that the degree of cross-linking can be controlled by varying the exposure time.

ISSN:0920-5063    

DOI:10.1163/156856295X00535

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Thin films of both pure soluble collagen (CLG) and poly(vinylalcohol) (PVA) and mixtures of the two, ranging from 20-80% PVA composition were studied to test the effects of PVA content and of glutaraldehyde vapour cross-linking. Both the thermal and mechanical behavior and, in addition, proteolytic stability were clearly influenced by the ratio of CLG/PVA. The experimental results indicate that no thermodynamic compatibility occurs between the two homopolymers. However, there is evidence that strong interactions, probably due to hydrogen bond formation, occur between the biological and synthetic polymers. The interactions appear stronger in those films with a lower PVA content and which were not cross-linked. Both the thermal and biological stability are increased and there is an improvement of the mechanical properties. The mutual intermolecular influence appears to allow the attainment of a good mechanical compatibility between CLG and PVA.

ISSN:0920-5063    

DOI:10.1163/156856295X00544

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Many types of proprietary processing aids are used by the manufacturers of polymer medical devices, which are difficult to completely eliminate from the end product. In such cases, it is important to investigate how such processing aids affect the properties of the materials. One such material is Pellethane and a most commonly found processing aid is wax. We investigated the effect of the presence of such wax on hecompatibility properties, particularly on the adhesion and activation of human platelets, on a group of Pellethane samples with varying amounts of wax. The effectiveness of cleaning agents, like Freon, was examined for wax removal. The type and quantity of wax present within the near-surface regions of the Pellethane tubings was estimated by using the FT-IR-ATR technique. The presence of bis amide processing wax was found to affect the hemocompatibility properties of the Pellethane samples. Correlation between hemocompatibility and the amount of wax was made; platelet activation, as well as amount and density of fibrin formation, showed a linear correlation.

ISSN:0920-5063    

DOI:10.1163/156856295X00553

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Poly(methyl methacrylate-methacrylic acid-2-hydroxyethyl methacrylate) latex (ACRYLAT) was synthesized by radical precipitation polymerization. The mass median diameter (MMD) and the geometical standard deviation (GSD) of the ACRYLAT particles were 138 nm and 1.2, respectively. The concentration of the titrable carboxylic groups in the surface layer of latex particles was equal to 8.41 × 10-6mol m-2. Latex was able to bind up to 2.82 × 10-7mol of 1-aminopyrene per 1 m2of the surface of the latex particles due to the ionic interactions between carboxylate anions and ammonium cations of protonated 1-aminopyrene. ACRYLAT was able to immobilize covalently human serum albumin in amounts up to 0.23 mg m-2. Aggregation of ACRYLAT with immobilized HSA, induced with specific antibodies (anti-HSA), was investigated turbidimetrically. The results indicated that in the model turbidimetric immunoassay, ACRYLAT coated with HSA can be used for the detection of anti-HSA in the goat anti-HSA serum diluted from 50 to 7000-fold. Immobilization of rabbit antibodies to plasminogen (anti-Plg) to ACRYLAT via the ε-aminocaproic acid linkers provided particles which were used for the development of the turbidimetric immunoassay for plasminogen. In this assay plasminogen could be detected in concentration ranging from 0.75 to 75μg ml-1in the blood plasma.

ISSN:0920-5063    

DOI:10.1163/156856295X00562

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The tetrapeptide, Arg-Gly-Asp-Ser (RGDS), which corresponds to a core sequence of cell adhesion proteins, was coimmobilized with insulin on to surface-hydrolyzed poly(methyl methacrylate) film. Adhesion of STO mouse fibroblast cells was enhanced by the immobilization of RGDS, but not of insulin. On the other hand, growth of the cells was accelerated by the insulin immobilization, but not by the RGDS immobilization. Coimmobilization of insulin and RGDS did not affect cell adhesion but accelerated cell growth remarkably. This acceleration effect is considered to be attributable to a prolonged interaction of immobilized insulin and insulin receptor by adhesion enhancement, and to a postulated interaction between activated insulin receptor and integrin.

ISSN:0920-5063    

DOI:10.1163/156856295X00571

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Copolymerization of NN-dirnethylacrylamide (DMAA) and p-acryloyloxiacetanilide (AOA) was carried out at different mole ratios of the monomers to obtain copolymers of varying compositions. DMAA contents were very near to the corresponding monomer feed and varied between 0.20 and 0.80. Investigation of the protein adsorption of these polymer surfaces showed that copolymers with higher DMAA content adsorbed more albumin than fibrinogen. The scanning electron micrographs of the polymer-coated coverslips after contact with blood showed an antithrombogenic behaviour of these surfaces.

ISSN:0920-5063    

DOI:10.1163/156856295X00580

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper reports quantification of a method for measuring amounts of protein adsorbed to a surface; the method is especially useful for revealing macroscopic spatial patterns of adsorption. The experiments tested the effectiveness of iron oxide suspensions adsorbed onto the adsorbed protein to indicate, in separate trials, the amount of either human plasma fibrinogen or human serum albumin (HSA) present on glass slides. Corresponding trials, using radioactively labeled proteins, were performed to calibrate the amount of either albumin or fibrinogen adsorbed onto similar slides out of solutions of varying bulk concentrations. The oxide deposits were quantified using a scanner and an image analysis program. The isotherms produced from the collected data indicate a continuous, monotonic correlation between light absorbed by adherent oxide and surface concentration of protein. The same correlation applies to albumin and fibrinogen when surface concentrations are expressed in weight units. These results confirm that patterns of oxide deposition correspond to patterns of protein deposition and show clearly how qualitative observations, such as those previously reported, can be made quantitative with scanning and digital image analysis.

ISSN:0920-5063    

DOI:10.1163/156856295X00599

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0920-5063    

DOI:10.1163/156856295X00607

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor