Biomedical subjects

Changxiu Wan

Publications and source records attributed to Changxiu Wan.

11 recordsLinked to original sources

PubMed2006

[Research on intelligent controlled drug delivery with polymer].

The intelligent controlled drug delivery systems are a series of the preparations including microcapsules or nanocapsules composed of intelligent polymers and medication. The properties of preparations can change with the external stimuli such as pH value, temperature, chemical substance, light, electricity and magnetism. According to this properties, the drug delivery can be intelligently controlled. This paper has reviewed research on syntheses and applications of intelligent controlled drug delivery systems with polymers.

Delayed-Action Preparations↗

PubMed2006

[Progress in study of self-assembling peptides].

Self-assembly of peptides is ubiquitous in the body of creatures. The molecules of peptides combine with each other to form proteins with different functions through self-assembly. The formation of a specific conformation of one type of protein is owing to the self-assembly of its compositive amino acids. So, researchers can design self-assembly of peptides at the molecular level and can control its formation and configuration. It has the potential for application in the preparation of new medicines and biomaterials. In recent years, self-assembling peptides have been increasingly high-lighted and used to simulate the function of natural biomolecules, to synthesize peptide-medicine, and to serve as the carriers of medicine.

Biocompatible Materials↗

PubMed2006

[Structure and performance of calcium polyphosphate for bone tissue engineering].

Porous calcium polyphosphate (CPP) has shown promise of tissue engineered implant application because of the biocompatibility and biodegradation. CPP with different polymerization degree were prepared by controlling the calcining time, and its polymerization degree could be calculated by developed method in this paper. Different crystal types CPP were prepared by quenching from the melt and crystallization of amorphous CPP. From the in vitro degradation, carried out in Tris-HCl buffer, the degradation velocity of CPP was controllable. The weight loss of CPP with different polymerization degrees and crystal types were different. With the increasing of polymerization degree, the weight loss during the degradation was decreasing, contrarily the strength of CPP was increasing. The amorphous CPP could degrade completely in 17 days while gamma-CPP do completely in 25 days. The degradation velocity beta-CPP and alpha-CPP was slower than gamma-CPP and the weight loss was about 12% and 5% respectively. The results of this study indicate that CPP have potential applications for bone tissue engineering as inorganic polymeric biomaterials.

Absorbable Implants↗

PubMed2005

[Effect of RGD peptide on adhesive stability of human umbilical vein endothelial cell on polyethylene terephthalate surface].

In this study for exploring the effect of RGD peptide on adhesive stability of endothelial cells biomaterial surface, all materials were divided into three groups, RGD group (PET covalently grafted synthetic RGD peptides), control group (PET precoated with fibronectin) and blank group (Non-coated surface). Cultured human umbilical vein endothelial cells (HUVECs) were seeded on the materials, then adhesive stability of HUVECs on the varied PET surfaces was observed under steady flow condition, and effects of shear stress and shear time on adherent cells were compared. The results showed that the resistance adherent endothelial cells to detachment by flow was shear stress and shear time dependent. Comparison three groups under the same condition revealed that the ECs retention rates of RGD-grafted or fibronectin-coated group were much higher than that of the non-coated group. Under 8.19 dyne/cm2 shear stress after 4h, retention rates were 13.73% (blank group), 43.33% (RGD group) and 40.75% (control group) respectively. These data indicated that RGD peptide can improve the adhesive stability of endothelial cell on biomaterial and the effect of RGD in vivo needs further studies.

Biocompatible Materials↗

PubMed2005

[Advances in research on calcium polyphosphate bioceramic for bone tissue engineering scaffold].

Bone tissue engineering is a novel, developing and challenging science which provides a new way to repair bone lost from injury and disease. Porous calcium polyphosphate bioceramic is one kind of absorptable bioceramic. Owing to its fine biocompatibility and degradability, more and more pieces of research wark have been carried out in bone tissue engineering, and because of its special characteristics, calcium polyphosphate bioceramic is regarded as a promising material for solving the problem of how to match the degradation velocity of scaffold with the velocity of cell growth. The recent research of using calcium polyphosphate bioceramic as the scaffold in bone tissue engineering is summarized, including the property, synthesis and advances.

Bone Substitutes↗

PubMed2004

[Biocompatibility study of the UV surface modified Dacron material].

The enzyme histochemistry method was used in this experiment to study the biocompatibility of the UV surface modified Dacron. The activity of the enzymes such as ALP, ACP, NADHD and LDH in the tissue surrounding both the modified and unmodified materials after a certain implantation period was semiquantitatively measured. The results showed that the biocompatibility of the surface modified Dacron was as good as that of the unmodified one.

Biocompatible Materials↗

PubMed2004

[The advance in researches for biomedical intelligent polymer materials].

The properties of biomedical intelligent polymer materials can be changed obviously when there is a little physical or chemical change in external condition. They are in the forms of solids, solutions and polymers on the surface of carrier, including aqueous solution of hydrophilic polymers, cross-linking hydrophilic polymers (i.e. hydrogels) and the polymers on the surface of carrier. In this paper are reviewed the progress in researches and the application of biomedical intelligent polymer materials.

Biocompatible Materials↗

PubMed2003

[Investigation of the degradation behavior of different modified bovine pericardial in vitro].

Bovine pericardium is mainly composed of collagen which has many good properties of extracellular matrix. This in vitro study was performed to quantitatively investigate and compare the degradation behavior of the bovine pericardial, which were modified with different methods. The purpose is to find out one method that presents not only the degradation regularity of material but also minimum antigenicity, so that bovine pericardium can be used as a well degradable guide tissue regeneration material. The results of the experiments showed that the bovine pericardium treated with ethanol is more appreciated than that treated with epoxy cross-linking agent or glutaraldehyde. The mensuration of protein and special amino acid may be a useful base of constructing a mathematic model for further researches on the rate of degradation of bovine pericardium.

Animals↗

PubMed2003

[Research in synthesis of bioactive peptide RGD and the method for its grafting on PET surface].

The aim of this experiment is to graft synthesizing Arg-Gly-Asp peptides (RGD) on the surface of polymer materials, combine endothelial cells with its special site, enhance the adhesion of endothelial cells on the surface, promote the blood compatibility of the biomaterials. Carboxy group (-COOH) was grafted on the materials surface by ultraviolet (UV) radiation, and the RGD serial obtained by liquid phase synthesis was successfully grafted on the disposed materials by chemical reaction. The endothelialization experiment was made also. The grafting results were measured by X-ray photoelectron spectroscopy (XPS), and endothelialization was observed using optical microscope and scanning electron microscope (SEM). The results indicated that the method improves the effect of materials endothelialization. The experiment has made successful use of UV grafting and chemical coupling methods to graft bioactive RGD onto PET film surface. This is a new method of grafting bioactive peptide.

Biocompatible Materials↗

PubMed2003

[The advance of bioactive peptide RGD in the research of bone regeneration].

Clinically, there has been so far no effective way to repair the bone-missing of large extent due to gash, infection and removal of tumor. The solution of this problem can be assisted by the addition of bioactive substances to substrate materials, because the growth of peripheral tissue and the fiber tissue growing the materials can be induced to the direction of bone-tissue by these biomaterials with bioactive peptides. The peptide Arg-Gly-Asp is the point between the integrin which comes from membrane and the ligand. In certain cases, the artificially synthesized RGD can be competitively combined with the integrin on cell surface, and outer-cell information is transmitted into cells, which will cause a series of physiological changes in cells. Presently, it is reported that the RGD has the ability to induce the growth of osteoblasts, restrain the adhesion between osteoclasts and substrates. This paper reviews and introduces the progress made with the work of RGD-inducing bone regeneration.

Biocompatible Materials↗

PubMed2002

[The study of photochemical immobilization of urease on polyether sulfone film surface].

A new method of using photoactivable ester with azido group was described to immobilize urease on polyether sulfone(PES) film surface. The effects of photoactive enzyme concentration, temperature, pH, irradiation time on the activity of immobilized urease were investigated. Reused times and storage stability were also studied. The results showed that the surface concentration of urease immobilized on PES surface was about 0.33 mg/cm2. When the irradiation time was 5 minutes, the relative activity of immobilized urease was the highest and the activity increased with the increase of the concentration of photoactive urease solution. The optimum pH and temperature of immobilized urease were 7 and 50 degrees C respectively. The relative activity of immobilized urease was stable (50%) after 12 times reused at 50 degrees C.

Enzyme Stability↗