Ainslie Kristy M, Sharma Gaurav, Dyer Maureen A, Grimes Craig A, Pishko Michael V
Materials Research Institute, Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Nano Lett. 2005 Sep;5(9):1852-6. doi: 10.1021/nl051117u.
The research described here investigates the hypothesis that nanoarchitecture contained in a nanowire array is capable of attenuating the adverse host response generated when medical devices are implanted in the body. This adverse host response, or biofouling, generates an avascular fibrous mass transfer barrier between the device and the analyte of interest, disabling the implant if it is a sensor. Numerous studies have indicated that surface chemistry and architecture modulate the host response. These findings led us to hypothesize that nanostructured surfaces will inhibit the formation of an avascular fibrous capsule significantly. We are investigating whether arrays of oscillating magnetostrictive nanowires can prevent protein adsorption. Magnetostrictive nanowires were fabricated by electroplating a ferromagnetic metal alloy into the pores of a nanoporous alumina template. The ferromagnetic nanowires are made to oscillate by oscillating the magnetic field surrounding the wires. Radiolabeled bovine serum albumin, enzyme-linked immunosorbent assay (ELISA), and other protein assays were used to study protein adhesion on the nanowire arrays. These results display a reduced protein adsorption per surface area of static nanowires. Comparing the surfaces, 14-30% of the protein that absorbed on the flat surface adsorbed on the nanowires. Our contact angle measurements indicate that the attenuation of protein on the nanowire surface might be due to the increased hydrophilicity of the nanostructured surface compared to a flat surface of the same material. We oscillated the magnetostrictive wires by placing them in a 38 G 10 Hz oscillating magnetic field. The oscillating nanowires show a further reduction in protein adhesion where only 7-67% of the protein on the static wires was measured on the oscillating nanowires. By varying the viscosity of the fluid the nanowires are oscillated in, we determined that protein detachment is shear-stress modulated. We created a high shearing fluid with dextran, which reduced protein adsorption on the oscillating nanowires by 70% over nanowires oscillating in baseline viscosity fluid. Our preliminary studies strongly suggest that the architecture in the static nanowire arrays and the shear created by oscillating the nanowire arrays would attenuate the biofouling response in vivo.
纳米线阵列中的纳米结构能够减轻医疗设备植入体内时产生的不良宿主反应。这种不良宿主反应，即生物污垢，会在设备与感兴趣的分析物之间形成无血管的纤维状物质传输屏障，如果植入物是传感器，就会使其失效。大量研究表明，表面化学和结构会调节宿主反应。这些发现使我们推测，纳米结构表面将显著抑制无血管纤维囊的形成。我们正在研究振荡磁致伸缩纳米线阵列是否能防止蛋白质吸附。通过将铁磁金属合金电镀到纳米多孔氧化铝模板的孔中制备了磁致伸缩纳米线。通过振荡围绕纳米线的磁场使铁磁纳米线振荡。使用放射性标记的牛血清白蛋白、酶联免疫吸附测定（ELISA）和其他蛋白质测定方法来研究蛋白质在纳米线阵列上的粘附情况。这些结果显示，静态纳米线每单位表面积的蛋白质吸附量减少。比较这些表面，在平面上吸附的蛋白质有14% - 30%吸附在了纳米线上。我们的接触角测量表明，纳米线表面蛋白质的减少可能是由于与相同材料的平面相比，纳米结构表面的亲水性增加。我们通过将磁致伸缩线置于38 G 10 Hz的振荡磁场中来使其振荡。振荡的纳米线显示出蛋白质粘附进一步减少，在振荡纳米线上测得的蛋白质仅为静态纳米线上的7% - 67%。通过改变纳米线在其中振荡的流体的粘度，我们确定蛋白质的脱离是由剪切应力调节的。我们用葡聚糖创建了一种高剪切流体，与在基线粘度流体中振荡的纳米线相比，它使振荡纳米线上的蛋白质吸附减少了70%。我们的初步研究强烈表明，静态纳米线阵列中的结构以及振荡纳米线阵列产生的剪切力将减轻体内的生物污垢反应。
