Papers by Author: Shao Xing Qu

Abstract: The purpose of this paper was to investigate the effect of various Chinese medicine adding methods on their contents in calcium phosphate (CaP) and the crystal structure of the CaP comparatively. In the present study, CaP was synthesized by the wet chemistry method, in which starting reagent grades calcium nitrate and diammonium phosphate were used as the molar ratio Ca/P=1.5. Chinese medicine parenteral solution, Salvia Miltirrhiza Bunge (SMB), was added into the Ca2+ and PO43- reactive solutions before, during or after synthesis process. CaP was synthesized without adding SMB as the control. UV-VIS spectrophotometer was used to measure the supernatant absorbency. Zeta potential was used to characterize the various CaP slurries. Thermogravimetry, X-ray diffraction and transmission electron microscope were used to characterize the various powders, respectively. The presented results showed that adding SMB during the reaction can obtain the maximal medicine content among the four different adding methods. There was a slight effect on the crystal structure of CaP by adding SMB.

Abstract: In this study, biodegradable poly-lactic-acid (PLA) microspheres encapsulated with Salvia Miltiorrhiza Bunge (SMB), ranged from 100µm to 300µm, were prepared by a solvent evaporation method. Those PLA microspheres mixed with CPC powder, at a mass fraction of 0.2 to 0.8, to yield a self-emerged porous CPC. The surface morphology of PLA microspheres and CPC were observed by optical microscopy and scanning electron microscopy (SEM), respectively. The function groups of PLA microspheres and the phase composition of CPC were analyzed by Fourier transform infrared spectrometer (FTIR) and X-ray diffraction (XRD) , respectively. A preliminary study of drug release was performed by immersing PLA microspheres and CPC into simulated body fluid (SBF) for a various interval points. And the concentrations of SMB in SBF were measured by UV-VIS spectroscopy. The present results showed that the self-emerged porous CPC containing Chinese medicine could be prepared by adding biodegradable PLA microspheres. PLA microspheres can promote the CPC aqueous reaction to form final product, hydroxyapatite (HA).

Abstract: Hollow hydroxyapatite microspheres (H-HAMs) with controlled characteristic mesoporous structure on the shell were successfully fabricated by using core template technology and sol-gel process. The fabrication of H-HAMs mainly included three distinct steps: the preparation of core template spheres of chitin by emulsifying chitin solution in oil, the formation of core-shell composite spheres of chitin-HA/chitin after a layer of chitin/HA solution coated on the surface of chitin core templates by means of a gelling process of chitin solution with the help of water in the cores, and the harvest of H-HAMs through a special sintering procedure to remove chitin. The size and shape of H-HAMs were chiefly determined by the size and morphology of core templates. The thickness of shells was easily controlled by altering water content of the starting template particles, and the characteristic mesoporous structure on the shell was related to the proportion of chitin in the chitin/HA composite solution and the sintering temperature. H-HAMs with characteristic mesoporous architecture on the shell have many potential applications such as used as a carrier for sustained release of drugs in the therapy of hard tissue system.

Abstract: Influence of heat-treatment conditions on wear resistance of titanium was investigated. Titanium plates were subjected to heat-treatment in air and water vapor respectively. Heat-treatments increased micro-hardness of titanium. The plate heat-treated in air (H) has the highest roughness and the plate treated in water vapor (W) lowest. After heat-treatment surface oxide was rutile. The friction coefficient of W was the lowest and almost stable at about 0.18. Non-heat--treated titanium plate (S) had a highest coefficient up to 1.1. Wear resistance of heat--treated titanium, especially W was significantly superior to non-treated titanium. The wear of S resulted mainly from adhesion failure, H involved with abrasive wear and fatigue failure. For W, a complex wear mechanism was probably existed.

Abstract: A microporous apatite coating was fabricated by a heat-oxidation and chemical routine. The morphology, composition and structure were characterized by scanning electron microscopy with X-ray energy dispersion spectroscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The components of the coating were predominantly apatite, next tri-calcium phosphate and octa-calcium phosphate. The pore size ranged from 1µm to5µm. The thickness of the coating was about 6µm ~ 10µm. The microporous coating was Ca-deficient carbonate apatite.

Abstract: Hydroxyapatite (HA) spherulites had been fabricated successfully through a novel approach including chitin emulsion and geletion processes. The freeze-dried nano-HA powder was firstly dispersed in the chitin solvent before chitin dissolves in its solvent completely. The chitin sol containing nano-HA particles was dropped into oil and emulsified making use of liquids immiscibility effect between oil and chitin sol by stirring. The n-HA/Chitin sol spherulites gelled in situ with the existence of water molecules. Subsequently, the spherular gel granules were rinsed in distilled water to leach the solvent and dried in room circumstance. Finally, special sintering routines were carried to harvest spherular HA granules. The size and porosity of HA spherulites were controlled by the rate of nano-HA to chitin, the chitin concentration in the starting slurry, the stirring rate and the temperature of oil etc. In addition porosifier such as sugar was used in order to adjust the macro- and micro-porous structures in the HA spherulites. The morphological observation showed that the HA spherulites had good sphericity and characteristic microporous structure which were favorable for medical application.

Abstract: The purpose of this study was to investigate the in vitro degradation and release behaviors of calcium phosphate powders (Ca/P) containing Chinese Medicine for bone graft. Two kinds of Ca/P powders, one with the Chinese Medicine, Salvia Miltiorrhiza Bunge (SMB) and the other with Polyacrylic Acid (PAA) and SMB, were soaked in simulated body fluid (SBF) for up to 150h. The in vitro release of SMB was measured by UV-VIS spectroscopy. The Ca2+ concentrations and pH of SBF soaked Ca/P powders were measured by AAS and pH meter. TA and XRD were employed to analyze various Ca/P powders before and after soaked in SBF, respectively. The results demonstrated that a faster SMB release occurred during the first 24 hours, while a slow release was sustained up to150h. Furthermore, the released of SMB in Ca/P-PAA-SMB was faster than that of Ca/P-SMB. It was concluded that a controllable release of Chinese Medicine from Calcium phosphate may be carried out by the addition of suitable surfactant. Accordingly, calcium ions were released into SBF, which was benefit for bone tissue repairing and reconstructing. Additionally, the TA results showed that there was 1.66% SMB released from Ca/P-SMB-PAA powders. XRD confirmed that various Ca/P powders possessed poorer crystallinity and smaller grain size.

Abstract: The influence of calcium (Ca) at titanium surface on co-precipitation of Ca-P and bovine serum albumin (BSA) has been investigated by scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The titanium surface containing Ca was prepared by immersing titanium plates into a saturated calcium hydroxyl (Ca(OH)2) solution. A solution containing BSA, calcium and phosphate ions was used for the co-precipitation test. Both BSA and calcium phosphate co-precipitated onto titanium surfaces with and without Ca. For the former, however, a thicker carbonate apatite coating, which consisted of finer crystal grains, formed and more protein precipitated compared to the surface without Ca. These results indicated that Ca at the titanium surface was favorable to the co-precipitation of BSA and Ca-P. Moreover, chemical interactions probably occurred during the co-precipitation of BSA and Ca-P.

Abstract: Porous blocks of bioactive ceramics are a more preferable tissue substitute to replace and reconstruct the defected tissues in that their interconnective pores are beneficial to new tissue ingrowth. The most important specification requires the controlled interconnective pores with required mechanical strength. A novel chitin-gel-cast approach is utilized to prepare porous bioceramic blocks. In order to improve their interconnection of pores, several acids are selected to etch the windows between porous. Light microscope (LM) and Scanning electronic microscope (SEM) are used to investigate the etching effect on the windows and walls of porous blocks. The results show that the acid etching can improve the interconnection of porous blocks with slight decrease of compressive strength under carefully controlled process conditions.