Papers by Author: Li Liao

Abstract: 5-Fluorouracil-poly(L-lactide) (5-Fu-PLLA) microspheres have been co-precipitated in a process namely solution-enhanced dispersion by supercritical CO2 (SEDS). First, the 5-Fu is successfully micronized and then used to produce the 5-Fu-PLLA microspheres. The 5-Fu-PLLA microspheres synthesized in the SEDS process exhibited a rather spherical shape, smooth surface, and a narrow particle size distribution, where it ranged from 531 nm to 1280 nm, with a mean particle size of 793 nm. The dichloromethane residue in the 5-Fu-PLLA microspheres is 46 ppm. The average drug load of the 5-Fu-PLLA microspheres is 12.7%. The results of this study indicate that the SEDS process is an effective technique to co-precipitate 5-Fu and PLLA as composite microspheres.

Abstract: The ability of apatite to form on the surface of biomaterials in simulated body fluid (SBF) has been widely used to predict the bone-bonding ability of bioceramic and bioceramic/polymer composites in vivo. Porous β-tricalcium phosphate/poly(L-lactic acid) (β-TCP/PLLA) composite scaffold was synthesized by new method. The ability of inducing calcium phosphate (Ca-P) formation was compared in static simulated body fluid(sSBF) and dynamic simulated body fluid (dSBF). The Ca-P morphology and crystal structures were identified using SEM, X-ray diffraction and Fourier transform infrared (FT-IR) spectroscopy. The results showed that the typical features of bone-like apatite formation on the surface and the inner pore wall of β-TCP/PLLA. Ca-P formation on scaffold surfaces in dSBF occurred slower than in sSBF and was more difficult with increasing flow rate of dSBF. The ability of apatite to form on β-TCP/PLLA was enhanced by effect of each other that has different degradable mechanism. Porous β-TCP/PLLA composite scaffold indicates good ability of Ca-P formation in vitro.

Abstract: To increase the mechanical properties of PLA used for fracture inner fixation, β-calcium metaphosphate whiskers were prepared by controlled crystallization in the glass. The factors influencing the morphology of the samples, such as component, time and temperature of crystallization were discussed. Results showed that the high quality of β-calcium metaphosphate whiskers can be obtained by crystallization treating for 36 hours and washing for 48 hours at 80°C distilled water. β-calcium metaphosphate whiskers having high aspect ratios of 20-100 with diameters of 1-5μm were achieved at the optimized conditions.