Jamshidi K, Shimizu T, Usui Y, Eberhart R C, Mooney V
Department of Surgery, University of Texas Southwestern Medical Center, Dallas 75235-9031.
ASAIO Trans. 1988 Jul-Sep;34(3):755-60.
The long-term goal of this research is to assist the resurfacing of damaged articular cartilage. Coralline hydroxyapatite (HA) was coated with a thin film of polylactide (PLa), maintaining pore structural characteristics. Cylindrical plugs (3 x 7 mm) implanted in non-load-bearing femoral and tibial diaphyses of the rabbit indicated substantial bone ingrowth at 3 weeks, with no significant difference between coated and uncoated HA in the amount and distribution of new bone. PLa-epsilon caprolactone polymeric negative replicas of coral Goniopora (G), inserted into the rabbit femur for 4 wks, showed newly formed bone grown deeply into the pores. Tight attachment of new bone to the implant and minimal inflammatory response suggested an osteocompatible reaction. In order to maintain the desirable pore structure of G while introducing controllable degradation rate and mechanical properties, a novel technique was employed to replicate G with PLa and its co-polymers. An intermediary negative replica of G was prepared with aspirin. A co-polymer positive replica of G was then prepared by solution or melt infusion into the negative replica; the aspirin was removed by methanol. A macro- (300-500 microns) and microporous (5-15 microns) structure was prepared by freeze-drying. This replica received appreciable bone ingrowth when implanted in the rabbit tibia for 3 wks. Our results demonstrate the feasibility of creating devices with interconnected pore structures and controlled porosity, elasticity, and mechanical strength sufficient for articular cartilage application, osteocompatibility, and controlled degradation rate.
本研究的长期目标是辅助受损关节软骨的修复。将聚丙交酯（PLa）薄膜涂覆在珊瑚羟基磷灰石（HA）上，同时保持孔隙结构特征。植入兔非负重股骨干和胫骨干的圆柱形栓体（3×7毫米）在3周时显示有大量骨长入，涂层HA和未涂层HA在新骨数量和分布上无显著差异。插入兔股骨4周的珊瑚角孔珊瑚（G）的聚丙交酯-ε-己内酯聚合物阴性复制品显示，新形成的骨深入孔隙生长。新骨与植入物紧密附着且炎症反应最小，表明存在骨相容性反应。为了在保持G所需孔隙结构的同时引入可控的降解速率和机械性能，采用了一种新技术，用PLa及其共聚物复制G。用阿司匹林制备G的中间阴性复制品。然后通过溶液或熔体注入阴性复制品制备G的共聚物阳性复制品；用甲醇除去阿司匹林。通过冷冻干燥制备宏观（300 - 500微米）和微孔（5 - 15微米）结构。该复制品植入兔胫骨3周时，有明显的骨长入。我们的结果证明了制造具有相互连接的孔隙结构、可控孔隙率、弹性和机械强度的装置的可行性，这些装置足以用于关节软骨应用、骨相容性和可控降解速率。
