Hasirci V, Lewandrowski K, Gresser J D, Wise D L, Trantolo D J
Middle East Technical University, Department of Biological Sciences, Biotechnology Research Unit, Ankara 06531, Turkey.
J Biotechnol. 2001 Mar 30;86(2):135-50. doi: 10.1016/s0168-1656(00)00409-0.
Biodegradable materials have various important applications in the biomedical field. There are basically two groups of polyesters which have significant importance in this field. These are polylactides and polyhydroxybutyrates. Both groups degrade via hydrolysis with the rates of degradation depending on medium properties such as pH, temperature, solvent and presence of biocatalysts, as well as on chemical compositions. In order for these biomaterials to be suitable for use in load bearing applications without deformation or warping their strengths and their capability to maintain their form must be improved. To insure dimensional stability during degradation and to match modulus and strength to that of bone, introduction of a reinforcing structure for those applications to plate fixation through the creation of an interpenetrating network might be a feasible approach. In this study, poly(lactide-co-glycolide) (PLGA), was the major structural element to be strengthened by a three-dimensional network or "scaffold" of another biodegradable polymer, poly(propylene fumarate) (PPF). PPF would be crosslinked with a biocompatible vinyl monomer, vinylpyrrolidone (VP). Three different approaches were tested to create dimensionally stable bone plates. First, via in situ crosslinking of PPF in the presence of PLGA. Secondly, by blending of precrosslinked PPF with PLGA. Finally, by simultaneous crosslinking and molding of the PLGA, PPF and VP. These were compared against extruded or compression molded PLGA controls. Results showed that compression molding at room temperature followed by crosslinking under pressure at elevated temperature and subsequently by gamma-irradiation appeared to yield the most favorable product as judged by swelling, hardness and flexural strength data. The composition of the implant material, PLGA(3):PPF(1):VP(0.7), appeared to be suitable and formed the compositional and procedural basis for in vivo biocompatibility studies.
可生物降解材料在生物医学领域有多种重要应用。在该领域中，基本上有两类聚酯具有重要意义。它们是聚丙交酯和聚羟基丁酸酯。这两类聚酯都通过水解降解，降解速率取决于介质性质，如pH值、温度、溶剂和生物催化剂的存在，以及化学组成。为了使这些生物材料适用于承重应用而不变形或翘曲，必须提高它们的强度以及保持其形状的能力。为确保降解过程中的尺寸稳定性，并使模量和强度与骨骼相匹配，通过创建互穿网络为那些用于钢板固定的应用引入增强结构可能是一种可行的方法。在本研究中，聚（丙交酯-共-乙交酯）（PLGA）是主要的结构元素，要通过另一种可生物降解聚合物聚（富马酸丙酯）（PPF）的三维网络或“支架”来增强。PPF将与生物相容性乙烯基单体乙烯基吡咯烷酮（VP）交联。测试了三种不同的方法来制造尺寸稳定的骨板。首先，通过在PLGA存在下对PPF进行原位交联。其次，将预交联的PPF与PLGA共混。最后，通过对PLGA、PPF和VP进行同时交联和模塑。将这些与挤出或压缩模塑的PLGA对照进行比较。结果表明，根据溶胀、硬度和弯曲强度数据判断，室温下压缩模塑，随后在高温下加压交联，然后进行γ射线辐照，似乎能得到最有利的产品。植入材料的组成PLGA(3):PPF(1):VP(0.7)似乎是合适的，并为体内生物相容性研究奠定了组成和程序基础。
