Papers by Keyword: Poly(DL-Lactic-Co-Glycolic Acid)

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Authors: Guo Ping Chen, Takashi Ushida, Tetsuya Tateishi
Authors: Z. Yang, E.S. Thian, Serena Best, Ruth Cameron
Abstract: α-tricalcium phosphate (α-TCP) was prepared by a wet precipitation reaction between calcium hydroxide and orthophosphoric acid solutions. The as-synthesised powder was then characterised using a Scanning Electron Microscope (SEM) equipped with Energy Dispersive Spectroscope (EDS), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscope (FTIR). Analyses revealed that a phase-pure powder with a Ca/P ratio of 1.5 was produced. In addition, nanosized α-TCP particles of diameter ~ 70 nm were agglomerated to form larger particles of 10μm in diameter. It was found that by the combination of attritor milling and solution evaporation, the agglomerates of α-TCP nanoparticles could be broken down, and distributed evenly within the poly(D,L-lactic-co-glycolic acid) (PLGA) matrix. Thus, a α-TCP/PLGA nanocomposite was successfully produced by a modified solution evaporation method at room temperature followed by hot pressing at 150 °C. The achievable ceramic loading was approximately 38 wt.%, which was confirmed by thermal gravimetric analysis (TGA).
Authors: Takashi Ushida, Tamotsu Tamaki, Guo Ping Chen, Yoshikazu Umezu, Tetsuya Tateishi
Authors: Z. Yang, E.S. Thian, Roger A. Brooks, Neil Rushton, Serena Best, Ruth Cameron
Abstract: In this study, a biocomposite comprising nanostructured α-tricalcium phosphate (α-TCP) in a poly(D,L-lactic-co-glycolic acid) (PLGA) matrix was fabricated by a modified solution evaporation method. As a potential temporary bone fixation and substitution material, its bioactivity was evaluated by its ability to form bone-like apatite layer in simulated body fluid (SBF). Owing to the increased surface area covered by the osteoconductive bioceramic of α-TCP, rapid apatite formation was observed. After 7 days of immersion, enhanced nucleation of apatite was observed on the nanocomposite. At day 14, dense lamellar-like apatite was formed on the nanocomposite whilst apatite nucleation had only just started to develop on the surface of pure PLGA. At the same time, a preliminary in-vitro cell culture study was conducted using human osteoblast-like (HOB) cells. A significant increase in cell number with culturing time was observed for the nanocomposite. After 9 days incubation, a confluent lamellar-like apatite layer was formed on the composite surface. This apatite layer was also shown beneath the proliferating HOB cells at Day 16.
Authors: Dong Lim Seol, Hyeong In Kim, Woo Jung Lee, Won Hee Jang, Jeong Koo Kim, Sung Jae Lee, Young Il Yang
Abstract: A culture system that is capable of providing even and uniform distribution and deposition of cells and extracellular matrix (ECM) is desired to enhance biological functions of the tissue-engineered artificial dermis (TEADs). For this purpose, we have developed a perfusion culture system that offers uniform exchange of nutrients and gases along the scaffold. Viability and effectiveness of the system were investigated by comparing biological and mechanical properties of TEADs. Results showed that the TEADs constructed by the perfusion culture system revealed significantly increased cell growth, ECM synthesis, and elastic modulus compared to those by the conventional static culture system. In addition, histological findings indicated that cells were more evenly distributed and ECM deposition increased in TEADs with the perfusion culture system. Therefore, it can be suggested that the perfusion culture system can constitute a more promising approach for constructing the TEADs.
Authors: Jin Hyun Chung, Hye Ryeon Lim, Tek Hyung Lee, Mi Hee Lee, Yeon I Woo, Hyun Sook Baek, Seung Jin Lee, Jeong Koo Kim, Jong Chul Park
Abstract: Poly (D,L-latic-co-glycolic acid) (PLGA) has been used as the artificial scaffold for blood vessel formation. In order to hinder smooth muscle cell (SMC) angiogenesis, new scaffold design method of loading Epigallocatechin 3-O-gallate (EGCG) on PLGA film was introduced. PLGA and EGCG were dissolved in acetone and film-shape scaffold was manufactured. Antiangiogenetic effect of EGCG released on scaffold was analyzed for SMC and human umbilical vein endothelial cell (HUVEC) and method for selective inhibition from the difference of growth of SMC and HUVEC was suggested.
Authors: Jia Shen Li, Arthur F.T. Mak
Abstract: This paper describes a novel method for coating hydroxyapatite (HA, Ca10(PO4)6(OH)2) nano-particles onto poly(DL-lactic-co-glycolic acid) (PLGA) scaffold. Paraffin micro-spheres were used as porogens to create porous scaffolds and as vehicles to transfer HA into PLGA scaffold. HA nano-particles / 50% ethanol suspension was mixed with paraffin micro-spheres. The paraffin micro-spheres / HA suspension were pressed together to form a paraffin scaffold. After it was dried, the HA was coated on the surface of the paraffin spheres. Then, PLGA solution was cast into the inter space among the paraffin micro-spheres and then the solvent was evaporated. Afterwards, the paraffin micro-spheres were dissolved and removed. PLGA scaffolds with controlled pore size, good interconnectivity and high porosity were obtained. The HA nano-particles were transferred from the paraffin surface to the surface of the pore wall throughout the PLGA scaffold.
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