Biomedical subjects

Changren Zhou

Publications and source records attributed to Changren Zhou.

7 recordsLinked to original sources

PubMed2007

Fabrication and characterization of PLLA-chitosan hybrid scaffolds with improved cell compatibility.

To combine the individual advantages of synthetic and natural polymers, poly(L-lactic acid) (PLLA)-chitosan hybrid scaffolds were fabricated. PLLA sponges were prepared by particulate-leaching, and then PLLA-chitosan hybrid scaffolds were obtained by dipping the PLLA sponges in chitosan solution and subsequently freeze-drying. Physicochemical properties of the scaffolds were characterized by scanning electron microscopy (SEM), water uptake test, and mechanical strength measurement. Moreover, cell adhesion, cell proliferation, and cell viability on the scaffolds were evaluated through osteoblast-like cell culture. The experimental results indicated that, PLLA sponges exhibited macroporous structure and the interconnected microporous structure of chitosan was formed within the macropores of PLLA sponges. The incorporation of chitosan reinforced PLLA sponges in dependence on chitosan content. The hybrid scaffolds had higher water uptake ability compared with PLLA sponges. Particularly, the hybrid scaffolds exhibited excellent cell attachment efficiency, cell proliferation, and cell viability. This study suggests that the hybrid scaffolds obtain good mechanical strength from PLLA and excellent cell compatibility from chitosan.

Animals↗

PubMed2006

Novel injectable calcium phosphate/chitosan composites for bone substitute materials.

In this study, a novel injectable bone substitute material was developed which consists of chitosan, citric acid and glucose solution as the liquid phase, and tricalcium phosphate powder as the solid phase. This material was moldable because of its paste consistency after mixing. We used four groups of cement to investigate the mechanical properties and biocompatibility of the new biomaterial in vitro, which were named group A (10% citric acid), B (15% citric acid), C (20% citric acid) and D (25% citric acid). The setting times of the cements were 5-30 min. X-ray diffraction analysis showed that the products were hydroxyapatite (HA) and dicalcium phosphate anhydrous. When the concentration of citric acid was increased, the compressive strength of specimen increased. Through the simulated body fluid test, we observed the material was bioactive. Group D could induce Ca and P ions to deposit the surface group D quickly. These results indicated that the concentration of citric acid in the liquid component affected the mechanical properties and bioactivity of cements. The cell cultivation test showed that the cytocompatibility of the new biomaterial was good. The method for preparing the novel bone substitute material is simple. The starting material is more readily available and cheaper than HA, poly(methyl methacrylate), and so on. The cement could have good prospects for medical application.

Animals↗

PubMed2006

[Preparation and biocompatibility of a novel cornea scaffold material].

A novel cornea tissue scaffold material was prepared with N-vinly pyrrolidome (NVP) and a biodegradable crosslinking agent by radical polymerization, using azoisobutyronitrile (AIBN) as initiator. Water absorption test and contact angle measure were conducted, and the degradation process of material was investigated. The biocompatibility evaluation was carried out by implantation of material in the rabbits, and by cell culture. The water absorption was over 104%, the contact angle was lower than 41degrees, and the degradation speed in vitro kept steady. The results of implantation in the rabbits showed that the material was almost degraded 3 months later and lots of collagen and cornea stroma cells appeared in it,but there was no inflammation around it. The result of epithelial cells culture showed that the cells conglutinated on the material, but no remarkable cytotoxicity was noted.

Animals↗

PubMed2005

[Fabrication and properties of a composite chitosan/type II collagen scaffold for tissue engineering cartilage].

OBJECTIVE: To develop a novel porous three-dimensional scaffold and to investigate its physico-chemical properties for tissue engineering cartilage. METHODS: Refined 88% deacetylation degree chitosan was prepared and dissolved in 0.2 mol/L acetate acid and fully mixed with highly purified porcine type II collagen in 0.5 mol/L acetate acid solution in a ratio of 4 to 1 (wt/wt). Freeze-drying process was employed to fabricate the composite scaffold. The construct was cross-linked by use of 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). A mechanical tester was utilized to determine the tensile strength change before and after cross-linking. The microstructure was observed via scanning electron microscopy (SEM). The lysozyme degradation was performed to evaluate the degradability of the scaffold in vitro. RESULTS: A bulk scaffold with desired configuration was obtained. The mechanical test showed that the cross-linking treatment could enhance the mechanical strength of the scaffold. The SEM results revealed that the two constituents evenly distributed in the scaffold and that the matrix was porous, sponge-like with interconnected pore sizing 100-250 microm. In vitro lysozyme degradation indicated that cross-linked or uncross-linked composite scaffolds had faster degradation rate than the chitosan matrix. CONCLUSION: Chitosan and type II collagen can be developed into a porous three-dimensional scaffold. The related physico-chemical tests suggest that the composite scaffold meets requirements for tissue engineered scaffold and may serve as an alternative cell-carrier for tissue engineering cartilage.

Cartilage↗

PubMed2003

[Preparation and biological evaluation of PLA/chitosan composite materials].

Hypersusceptibility test, pyrogen test, cell cultivation, and toxicity examination were applied in the biological evaluation of the poly(lactic acid) (PLA)/chitosan composite materials. The results indicated that all the materials were negative, conforming to the ISO10993-1. The cell could grow well on the surface of the materials. So the PLA/chitosan composite materials have good biocompatibility and can be planted in the body as scaffolds.

Animals↗

PubMed2002

[Novel scaffold materials for tissue engineering].

In this paper, the resorbable and degradable biomaterials often used in recent years are reviewed. These materials include natural and synthetical ones such as collagen, protein fiber, chitosan, polylactic acid (PLA), polyglycolic acid(PGA), polyanlydrides, etc.

Biocompatible Materials↗

PubMed2002

[Study on preparation and property of PLA/liquid crystal composite membranes].

In this paper we synthesised two kinds of hydrophilic liquid crystal, i.e. cholesteryl triethenyl glycol carbonate (TCC), cholesteryl tetraethenyl glycol carbonate (TeCC), which were blended with PLA with certain contents to form composite membranes. Contact angle test showed that the contact angle decreases with the increase of liquid crystal. The blood-compatibility of the composite membranes was assessed by blood clotting time and hemolysis ratio which showed that these PLA/liquid crystal composite membranes with the content of 30%-40% liquid crystal appeared to be beneficial in improving the blood compatibility and anticoagulation.

Biocompatible Materials↗