To develop a new kind of natural self-hardening bone-rehabilitative composite and to study the chemical and biomechanical properties and the biocompatibility of the natural self-hardening composite. The self-hardening composite was prepared by combination the natural hydroxyapatite (NHA) obtained from pig bones, chitosan, CaO and ZnO. The setting time, the exothermic temperature and the pH value of the self-hardening composite were performed during and after the hardening of the samples. Compressive strength of composite was measured 48h after the setting by using a universal testing machine and the microstructure of them was observed by using a SEM. Biological evaluations both in vitro and in vivo were also taken out. The setting time of self-hardening composite was 11.2

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.

Test circuits for the signal detection and the function electrical stimulation (FES) of neurons have been designed, implemented at first by using discrete devices and characterized off-body. The detecting circuit consisting of three-stage operational amplifiers has a controllable gain up to 105, a -3 dB bandwidth of 30 kHz, and an equivalent input noise of about 9 nV/(开方Hz). The FES circuit consisting of two-stage operational amplifiers has a bandwidth of more than 10 kHz and a variable gain from 20 dB to 60 dB can provide a current of more than 1 mA to a load of 10 kΩ. They are intended to connect with both cuff-type and stag-type microelectrodes. Integrated circuits (IC) for the neural signal process have been designed with features of low voltage and low power. A more biocompatible composite has been synthesized to modify the silicon and related material.

An effective method for the quantitative evaluation of proteins adsorbed on biomaterial surfaces has been developed. First, the kinetic behavior of a range of human fibrinogen (Fib) adsorbed onto polystyrene (PS) films was investigated by using a reflectometry interference spectroscopy setup. The specific molecular number of adsorbed proteins, Np, was then defined. According to the definition, the numbers of Fib molecules adsorbed on PS films were calculated. An atomic force microscope (AFM) was used to scan the lateral distribution of the Fib molecules adsorbed on the PS films. From the AFM images, the practical specific molecular numbers were obtained by direct counting of the molecules. In order that the adsorbed number of Fib molecules on a unit area of the PS films could be counted easily, the solution concentration of proteins was reduced to 5ag/mL (10－18g/mL). There was good consistency between the numbers calculated with the formula defined by us and the numbers counted from AFM images. Therefore, the results of the present study prove the validity of our definition of the specific molecular number of adsorbed proteins and the effectiveness of the reflectometry interference spectroscopy-based method for quantitative evaluation of adsorptive proteins.

介绍了一种牙科材料细胞毒性评定的新方法—MTT试验法。该比色法以MTT四唑为基质，只测定体外存活的细胞数量，具有快速、简便、灵敏等优点。其指标客观且能定量分析，显示了与其他细胞毒性测定方法良好的相关性。作者依据自己的经验，强调了建立细胞生长代谢标准曲线的必要性。