Poly(lactic acid) microspheres with different surface charges have been prepared by using cationic, anionic or nonionic surfactants as the microspheres' surface stabilizers. Embedded with these microspheres, the modified PLA membranes with different surface charges have been obtained. The test of stability by CLSM and the morphological test by SEM confirmed that we obtained the microspheres modified PLA membranes with different surface charges successfully. The chondrocyte compatibility test of these modified PLA membranes showed that the attachment, proliferation and activity of chondrocytes on the positive surface of the modified PLA were better than those of other modified PLA membranes. The positive charge on the surface of PLA membrane could improve the cell-compatibility of PLA well.
Animals ; Animals, Newborn ; Biocompatible Materials ; chemical synthesis ; Cations ; Lactic Acid ; chemical synthesis ; chemistry ; Membranes, Artificial ; Microspheres ; Polyesters ; Polymers ; chemical synthesis ; chemistry ; Rabbits ; Surface-Active Agents ; chemistry

The factors controlling the microstructure and properties of collagen-based bioactive artificial dermis are reviewed. The second component, the pore diameter and porosity, the thickness of scaffold, the bioactive factors as well as the cross-linking density that are important parameters of artificial dermis should be carefully researched and designed. Experiment methods controlling these parameters are suggested.
Biocompatible Materials ; chemistry ; Collagen ; chemistry ; Dermis ; cytology ; Humans ; Porosity ; Skin, Artificial ; Tissue Engineering ; methods

As regeneration scaffolds or templates in tissue engineering, polymeric materials play key roles in inducing tissue regeneration, and mediating cell growth and differentiation, i.e. functioning as artificial extracellular matrix. The polymeric materials including biological derived biopolymers and synthetic polymers, which are usually employed in tissue engineering, are reviewed in this paper.
Biocompatible Materials ; Cellulose ; Collagen ; Hyaluronic Acid ; Lactic Acid ; Polyesters ; Polymers ; Tissue Engineering

Three-dimensional cell scaffolds play an important role in tissue engineering. They can modulate cell response and guide the regeneration of tissues. Injectable scaffolds can mimic the chemical and physical environments of natural extracellular matrix, and can be easily applied in clinic with the merits of minor or nonsurgical operations. Hence, special care should be given to the use of this kind of scaffolds in tissue engineering hydrogels, and composites with other fillers have been used as a basic component to construct the injectable scaffolds. Most of these injectable scaffolds are applied to repair bone and cartilage. Experimental results have development of the injectable scaffolds in recent years. The advantages and disadvantages are discussed with the development of the injectable scaffolds in recent years. The advantages and disadvantages are discussed with the suggestions for future development.
Absorbable Implants ; Biocompatible Materials ; Bone and Bones ; physiology ; Cartilage ; physiology ; Guided Tissue Regeneration ; Humans ; Hydrogels ; Tissue Engineering ; methods ; Tissue Scaffolds

Attenuated total reflection (ATR) FT-IR spectroscopy was used to quantitatively characterize the extent of bovine serum albumin (BSA) adsorbed on the surface-coating-modified poly(ether urethane) (PEU) matrix. The two surface modifying additives (SMA) were respectively a tri-block-coupling-polymer of stearyl poly (ethylene oxide)-4,4'-methylene diphenyl diisocyanate-stearyl poly(ethylene oxide), for short MSPEO, and another similar block-coupling polymer with the Cibacron Blue F3G-A endgroups, for short cibaMPEO. The experiments of static BSA adsorption were composed by two parts. One was static isothermal adsorption, and the other was static adsorption kinetics. The quantitative characterization was based on the optical principles of FT-IR, method of experiment and index of the apparatus, by which the enhancement of BSA adsorption on the SMA-modified surfaces was confirmed.
Adsorption ; Animals ; Biocompatible Materials ; Cattle ; Polyethylene Glycols ; Polyurethanes ; Serum Albumin, Bovine ; metabolism ; Spectroscopy, Fourier Transform Infrared ; Stearates

Amphiphilic coupling-polymer of stearyl poly (ethylene oxide)-co-4, 4'-methylendiphenyl diisocyanate-co-stearyl poly(ethylene oxide), MSPEO, was specially designed as surface-modifying additives. The blends of MSPEO in both polyether urethane (PEU) and chitosan(Chi), as the coating materials for intravascular device were investigated. Two kinds of static clotting time tests, plasma recalcification time (PRT) and prothrombin time(PT), as well as the static platelet adhesion experiment were carried out. And the dynamic anti-coagulation experiment was performed with a closed-loop tubular system under a blood shear rate of 1,500 s-1. The results demonstrate that both blend coatings can improve the anti-coagulation of polyurethane greatly and will not lead to hemolysis, and that more platelets adhere to the surface modified by Chi-MSPEO blend coating as compared with those adhere to the surface modified by PEU-MSPEO blend coating. The surface modified by Chi-MSPEO has longer PRT, whereas the surface modified by PEU-MSPEO has longer PT.
Blood Coagulation Tests ; Chitin ; analogs & derivatives ; chemistry ; Chitosan ; Coated Materials, Biocompatible ; chemistry ; Ethylene Oxide ; chemistry ; Humans ; Materials Testing ; Platelet Adhesiveness ; Polymers ; chemistry ; Polyurethanes ; chemistry ; Prothrombin Time ; Surface Properties

The schematic structure model, materials selection and microstructure modulation are introduced for the design of artificial dermis equivalent. The artificial skin should also possess a bilayer structure that imitates then natural skin, i.e. the top layer functions as a temporary epidermis which is composed of polymer elastomer that is permeable for moisture but not for water, the bottom layer is the skin regeneration template employing collagen based sponge. In addition to collagen, polysaccharides like glycosaminoglycan is also used in the artificial dermis equivalent in order to simulate the natural extracellular matrix of skin and to modulate the degradation rate. The pore size and morphology of collagen porous membranes can be controlled by variation of the pH value, concentration and freezing temperature. Hence, the microstructure of the dermis equivalent can be optimized. The collagen based artificial dermis equivalent thus fabricated may be an option to skin graft in the clinical treatment of full skin injuries and ulcers.
Biocompatible Materials ; Collagen ; Equipment Design ; Humans ; Models, Structural ; Polysaccharides ; Skin, Artificial ; Tissue Engineering

BACKGROUND: The restenosis occurs up to 20%-30% following metal coronary stent implantation. Under the support of the 863 program, the feasibility to treat coronary artery stenosis using a novel drug-eluting stent (DES) has been investigated to reduce restenosis. OBJECTIVE: A drug-eluting stent (rapamycin as drug mode) was implanted into porcine models of coronary stenosis. The safety and efficacy of the drug-eluting stent were observed and compared with bare-metal stent. DESIGN, TIME AND SETTING: A randomized controlled animal experiment was performed in the Fu Wai Hospital for Cardiovascular Disease between November 2003 and April 2004. MATERIALS: A novel bioinspired phospholipid copolymer was synthesized by free radical polymerization of stearyl methacrylate, β-hydroxypropyl methacrylateand 3-(trimethoxysilyl) propylmethacrylate. METHODS: Twenty-one pigs were randomly divided into 3 groups: bare-mental stent, drug-eluting stent, and polymer-coated stent. The treated stents pre-loaded onto a delivery system through the use of crimping instrument were implanted into pig's coronary artery, with 2 stents per pig. MAIN OUTCOME MEASURES: Determination of luminal diameter, luminal area, mean intimal thickness on and between the stents, neointimal area, percentage of luminal area restenosis, and damage index using an image analysis instrument. RESULTS: At 28 days after implantation, there was significant difference in mean intimal thickness on and between the stents, as well as neointimal area, between the DES and bare-metal stent groups (P < 0.05). The neointimal area was reduced by 44.87% in the DES group compared with the bare-metal stent group. No significant difference in percentage of luminal area restenosis was found between the DES and bare-metal stent groups, but P value equaled to 0.053, which was close to 0.05. In addition, no restenosis was found in the DES group. CONCLUSION: Rapamycin DES can markedly resist intravascular intimal hyperplasia and restenosis following stenting.

A novel crosslinkable coating for biomedical device was prepared by copolymerization of the constituent monomers via a free radical method. 1H-NMR and IR results indicated it had desirable structure. Surface characterization revealed that surface reorganization occurred in aqueous environment and a polyethylene oxied (PEO) enrichment surface was developed on coated surface. The in-vitro platelet-adhesion test and the plasma recalcification time(PRT) determination showed that the coated surface could resist the blood coagulation effectively.
Blood Coagulation ; Coated Materials, Biocompatible ; chemistry ; Cross-Linking Reagents ; chemistry ; Materials Testing ; Platelet Adhesiveness ; Polyethylene Glycols ; chemistry ; Surface Properties

A novel bioinspired phospholipid copolymer has been synthesized by the radical polymerization of poly2-Methacryloyloxyethylphosphorylcholine (MPC), stearyl methacrylate (SMA), hydroxypropyl methacrylate (HPMA) and trimethoxysilylpropyl methacrylate (TSMA). Contact angle results indicated that the coating surface rearranged to get a more hydrophilic surface at the polymer/water interface. The membrane mimic phosphorylcholine coating surface could resist the platelet adhesion and prolong plasma recalcification time significantly. Rapamycin was used as model drugs to prepare drug-eluting coating. The animal experiments showed that this novel drug-eluting stent could effectively prevent the phenomena of restenosis.
Angioplasty, Balloon, Coronary ; instrumentation ; Animals ; Coated Materials, Biocompatible ; Coronary Restenosis ; prevention & control ; Drug-Eluting Stents ; Female ; Humans ; Male ; Materials Testing ; Methacrylates ; chemistry ; Phosphorylcholine ; analogs & derivatives ; chemistry ; Pilot Projects ; Polymers ; chemistry ; Prosthesis Design ; Random Allocation ; Sirolimus ; chemistry ; Swine ; Swine, Miniature