Beauregard G P, James S P
Rocky Mountain Materials Research, Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado 80523, USA.
Biomed Sci Instrum. 1999;35:415-9.
A novel, biomimetic, interpenetrating polymer network (IPN) between poly-L-lysine (PLL) and ultra high molecular weight polyethylene (UHMWPE) has been synthesized in an attempt to decrease wear in joint prostheses. A biomaterial with a gradient IPN of cationic PLL and UHMWPE has been synthesized, in the surface of bulk UHMWPE, to recruit the poly-anion, hyaluronic acid, from the synovial fluid. It is hypothesized that the hyaluronic acid molecules and their associated hydration layer will improve lubrication between the articulating surfaces, thus lowering both friction and wear. The synthesis involves four steps. Silylation of the PLL-HBr to PLL-SiMe3 utilizing bis(trimethylsiyl)acetamide (BSA). Swelling of the UHMWPE in a solution of PLL-SiMe3/xylenes at 60 degrees C with ultrasonics. Crosslinking of the PLL-SiMe3 within the UHMWPE with 1,8-diisocyanatooctane (a.k.a. OMDI). Finally, de-swelling and drying of the IPN under vacuum at 50 C. Visual observations show an adhered film on the IPN surface. Reflective FTIR spectra contain the characteristic peaks associated with UHMWPE. Two additional peaks, at 3410 and 1690 cm-1, are associated with PLL. SEM shows a morphology dominated by PLL spheres with diameters ranging from < 1 micron up to 3 micron. This shows that the PLL-SiMe3 has been crosslinked by the OMDI and was not rinsed away by either xylenes or sonicated water rinses. High contact angle of the PLL in contact with the UHMWPE demonstrate that the PLL has been de-silylated and returned to its hydrophilic nature. The spheres attached to the surface of the UHMWPE indicate that PLL has infiltrated the UHMWPE physical network and is entangled there. XPS confirms the presence of nitrogen by a 3-5 atomic percent signal in the outer 100 A of the IPN surface.
为了减少关节假体的磨损，人们合成了一种新型的、仿生的、聚-L-赖氨酸（PLL）与超高分子量聚乙烯（UHMWPE）之间的互穿聚合物网络（IPN）。在块状UHMWPE表面合成了一种具有阳离子PLL和UHMWPE梯度IPN的生物材料，以从滑液中募集聚阴离子透明质酸。据推测，透明质酸分子及其相关的水化层将改善关节表面之间的润滑，从而降低摩擦和磨损。合成过程包括四个步骤。利用双（三甲基硅基）乙酰胺（BSA）将PLL-HBr硅烷化为PLL-SiMe3。UHMWPE在60℃的PLL-SiMe3/二甲苯溶液中超声溶胀。用1,8-二异氰酸辛酯（又名OMDI）使UHMWPE内部的PLL-SiMe3交联。最后，在50℃真空下使IPN去溶胀并干燥。肉眼观察显示IPN表面有一层附着的薄膜。反射傅里叶变换红外光谱包含与UHMWPE相关的特征峰。在3410和1690 cm-1处的另外两个峰与PLL相关。扫描电子显微镜显示其形态以直径范围从小于1微米到3微米的PLL球体为主。这表明PLL-SiMe3已被OMDI交联，并且未被二甲苯或超声水洗掉。PLL与UHMWPE接触时的高接触角表明PLL已去硅烷化并恢复其亲水性。附着在UHMWPE表面的球体表明PLL已渗透到UHMWPE物理网络中并在那里缠结。X射线光电子能谱通过IPN表面外100埃中3-5原子百分比的信号证实了氮的存在。
