The aim of this study is to investigate the adsorptive property of proteins on surfaces of three kinds of carbon films (DLC, CN0.088, and CN0.15) and the medical origin of PMMA. The carbon films were first synthesized by magnetron sputtering with different deposition parameters. The surface characteristics of both the carbon films and the original samples were then measured using a contact-angle meter. A modified Coomassie brilliant blue (CBB) protein assay (or Bradford method) was used to detect the amount of proteins adsorbed on the material surfaces after the pilot research for the optimal ratio of protein- to CBB-solution had been performed. The results of the pilot research show that the optimal ratio of protein- to CBB-solution is 1:3, and the protein adsorption results show that the sequence amounts of proteins adsorbed on four kinds of surfaces are DLC > CN0.088 > PMMA > CN0.15. This was the same as the hydrophobicity sequence of four kinds of surfaces obtained from the contact-angle test. However, the ratio of albumin to IgG (RA/I) adsorbed on the four surfaces has an order of PMMA > CN0.15 > DLC > CN0.088, which indicates the anti-thrombogenicity property of the four kinds of surfaces.

Using a biomedical sensor setup RIfS we have investigated the kinetic behavior of human albumin (Alb), human fibrinogen (Fib), and human immunoglobulin G (IgG) adsorbed onto surfaces of chitosan. Polystyrene (PS) was used as the control material in this study. The optical thickness of three kinds of proteins measured by RIfS was related to their molecular dimensions and potential orientations on a film surface. According to the operation principle of RIfS and the molecular dimensions of three kinds of proteins, the adsorbed layers of proteins onto the surface of chitosan and PS was calculated by using a newly introduced equation. The microstructure of the chitosan and polystyrene film and the surfaces with adsorbed proteins were imaged by atomic force microscopy (AFM). With AFM analyses the lateral distribution of the protein molecules on surfaces have been recognized. The results show that the number of adsorbed layers of the three proteins on the surface of chitosan are 0.635 for Alb, 0.158 for Fib and 0.0967 for IgG, and of polystyrene are: 0.577 for IgG, 0.399 for Fib, 0.336 for Alb. This study confirmed that RIfS is a useful tool for the analysis of plasma proteins adsorbed on a surface of biomaterials. Results show that at first on the surface of chitosan film much more Alb than Fib was adsorbed which demonstrated that chitosan has an antithrombus function. Secondly, on the surface of chitosan film more Alb and less Fib were adsorbed than on the surface of PS film, which demonstrated that chitosan has a better blood compatibility than polystyrene. Thirdly, the calculated layer number of the three proteins indicated that on both chitosan and PS substrates monolayer coatings form.

The aim of this study was to compare the plasma protein adsorptive property of the natural hydroxyapatite (HA) and the synthesized HA to human albumin (Alb), fibrinogen (Fib) and immunoglobulin G (IgG). Different methods such as reflectometry interference spectroscopy (RIfS) measuring, Fourier transform infrared spectroscopy (FTIR) analysis and weighing assessment were used to measure the adsorbed amount of Alb, Fib and IgG on the natural HA and the synthesized HA. To compare the adsorptive property of protein adsorbed on these two kinds of materials, the ratio of Alb/Fib (RA/F) and the ratio of Alb/IgG (RA/I) were calculated. The results from all three methods showed that the values of RA/F and RA/I obtained with natural HA were smaller than those obtained with synthesized HA, that indicated that the natural HA adsorbed more human fibrinogen than human albumin and thas it would enhance blood coagulation and in favor of bone repairing.

Objective: The aim of this study was to investigate the competitive adsorption of human albumin (Alb), human fibrinogen (Fib) and human immunoglobulin G (IgG) on surface of biomaterial based on the special molecular recognition and interaction between antigen and antibody with a biomedical sensor Reflectometry Interference Spectroscopy (RIfS). Materials and Methods: The RIfS setup used has been developed in our laboratory (1). The materials to be tested were polyurethane (PU) and polystyrene (PS). The thin films of PU/PS were prepared using a spin-coating method. The thickness of the films was ~650 nm. Three kinds of proteins, Alb, Fib and IgG (Sigma Mo) were used as antigen and three kinds antibody used were sheep anti-human Alb, sheep anti-human Fib and rabbit anti-human IgG. 1. Investigation of interaction between three kinds of proteins alone with special antibodies: At first, the protein adsorption process has been performed as reported in (2). Then, bovine serum albumin (BSA) was added to fill in the areas of the material surface which were not covered by proteins and the PBS flowed over the surface of the PU/PS film to make cleaning. After such a treatment the special antibody solution flowed into the adsorption cell and the kinetic interaction process of antibody with proteins on the surface of the PU/PS film were oberseved in situ on the monitor of a computer. Until the kinitic adsorption curve of antibodies become stable, the PBS was driven into the adsorption cell again to wash off the antibodies which did not firmly adsorpted on the material surface. The wash process would get a response on the adsorption curve. For each kind of proteins, at least three tests were performed. 2. Performance of protein competitive adsorption: At first the protein adsorption process was performed with a mixture of three kinds of proteins (Aib:Fig:IgG=1:1:1). After mixed proteins were competitive adsorbed onto the surface of the PU/PS film, different antibodies were added to measure the interaction between the specific antibodys with each protein in mixed proteins layer adsorbed on the PU/PS film. 3. Caculation of the quantity of each protein in mixed protein layer that competitive adsorbed on the PU/PS: According to the results from 1 and 2, the percent of one kind of proteins in mixed protein layer competitive adsorbed on the surface of the material (Ppx ) was calculated with followed formula: Ppx=(Tp

In order to reform the traditional teaching methodology and to improve the teaching effect, we developed new teaching system for course “Biomedical Materials” in our university by the support of the computer technique and Internet. The new teaching system includes the construction of the multimedia courseware and web-based e-learning courses. More than 2000 PowerPoint slides have been designed and optimized and flash movies for several capitals are included. On the basis of this multimedia courseware, a web-based educational environment has been established further, which includes course contents, introduction of the teacher, courseware download, study forum, sitemap of the web, and relative link. The multimedia courseware has been introduced in the class teaching for “Biomedical Materials” for 6 years and a good teaching effect has been obtained. The web-based e-learning courses have been constructed for two years and proved that they are helpful for the students by their preparing and reviewing the teaching contents before and after the class teaching.