Papers by Author: Chang Sheng Liu

Abstract: A novel Ca/P-containing mesoporous silica-based xerogels (CaMSX) with good degradability and low heat generation were synthesized for hemorrhage control by a modified sol-gel process and physicochemically characterized. The mesoporous silica-based xerogels without Ca/P (MSX) was also prepared as comparison. The in vitro whole blood coagulation time, activated partial thromboplastin time (APTT) and prothrombin time (PT) of the CaMSX were measured with MSX, Chinese traditional medicin-Yunnan medical powder (YM) and traditional zeolite. In vivo bleeding model was tested with rabbit’ ear side veins. The results illustrated that the CaMSX could remarkably promote the intrinsic and extrinsic blood coagulation processes which greatly depend on the dosage and the content of Ca in the CaMSX. The CaMSX had better efficiency in promoting coagulation process than that of MSX, YM and zeolite.

Abstract: Nano-HAP (10-20nm) were obtained from East China University of Science and Technology. The osteoblasts were primary cultured from rat calvaria and then treated with five different concentrations(20，40，60，80，100µg/ml) of nano-HAP, the osteoblasts without nano-HAP was used as control group. Inhibition ratio, apoptotic rate were evaluated by MTT assay and flow cytometry (FCM), respectively. The specific surface area of nano-HAP was detected by BET. All date were expressed as mean ± standard deviation.Statistical analysis was performed by t test using software SPSS11.0 for Windows. The results indicated that the nano-HAP could inhibit the growth of osteoblasts in a dose-dependent manner. When the concentrations of nano-HAP were 20, 40, 60, 80, 100µg/ml, the inhibition ratio were 2.8%, 22.2%, 26.9%, 38% and 47.7%, and the apoptotic rate were 4.63%, 6.75%, 9.47%, 11.49%, 17.22%, respectively, which were obviously higher than that of control group. The nano-HAP significantly induced apoptosis in osteoblasts. There were the same tendency that the apoptotic and inhibition ratio of osteoblasts were rising with the increasing of the concentration of the nano-HAP. The specific surface area of nano-HAP was 148.140m2/g.

Abstract: Porous calcium phosphate cement (CPC) scaffolds were successfully fabricated utilizing particle-leaching method. Mesenchymal stem cells (MSCs) were cultured, expanded and seeded on the scaffolds and the proliferation and differentiation of MSCs into osteoblastic phenotype were determined using MTT assay, ALP activity and ESEM. The results revealed that the CPC scaffolds were biocompatible and had no negative effects on the MSCs in vitro. The in vivo biocompatibility and osteogenicity of the scaffolds were investigated. Both pure scaffolds and MSCs/scaffold constructs were implanted in rabbit mandibles and studied histologically. The results showed that CPC scaffolds exhibited good biocompatibility and osteoconductivity. Moreover, the introduction of MSCs into the scaffolds dramatically enhanced the efficiency of new bone formation initially.

Abstract: Hydroxyapatite (HAP)-forming calcium phosphate cement (CPC), due to the high biocompatibility, easy-to-shape characteristic, and the capacity to self-setting under ambient conditions, has been widely used for the repair of hard tissue defects. To satisfy the different clinical need, some modified CPC, including porous CPC, fast-biodegradable CPC, injectable CPC, water-resistant CPC, and rhBMP-2/CPC, have been designed and fabricated in recent years. This paper attempts to give an overview of different types of CPC that have being developed at the present time. Meanwhile, the application perspective of these modified CPC is also explored.

Abstract: In this paper, the hydration product of calcium phosphate cement with bioactive glass containing Si was used to investigate the effect of chemical composition on its bioactivity. The variation of concentrations of Ca2+, P and Si in TE solution complemented with electrolytes typical for plasma (TEE) and the formation of amorphous calcium phosphate layer on the surface of the materials were investigated by immersing the designed materials in TEE solution in vitro. The results showed that the composition of the bioactive composite CPC greatly affected its behavior in the solution and the formation of bioactive apatite. After immersed in TEE solution, the Ca ions were uptaken for all the samples, showing the decreases of Ca concentration during the entire duration, but the concentration of P ions increased sharply at the initial stage, and then decreased due to the formation of amorphous calcium phosphate layer on the surface of the materials. FTIR revealed that the layer was poorly crystallized Ca-deficient carbonate apatite. The thickness of the layer was more than 12 um, which layer was composed of rod-like apatite with directional arrangement. All the data obtained would be useful for the design and optimization of the orthopedic degradable implant inorganic materials.