Modulations of fluid flow inside the bone intramedullary cavity has been found to stimulate bone cellular activities and augment bone growth. However, study on the efficacy of the fluid modulation has been limited to external syringe pumps connected to the bone intramedullary cavity through the skin tubing. We report an implantable magnetic microfluidic pump which is suitable for in vivo studies in rodents. A compact microfluidic pump (22 mm diameter, 5 mm in thickness) with NdFeB magnets was fabricated in polydimethylsiloxane (PDMS) using a set of stainless-steel molds. An external actuator with a larger magnet was used to wirelessly actuate the magnetic microfluidic pump. The characterization of the static pressure of the microfluidic pump as a function of size of magnets was assessed. The dynamic pressure of the pump was also characterized to estimate the output of the pump. The magnetic microfluidic pump was implanted into the back of a Fischer-344 rat and connected to the intramedullary cavity of the femur using a tube. On-demand wireless magnetic operation using an actuator outside of the body was found to induce pressure modulation of up to 38 mmHg inside the femoral intramedullary cavity of the rat.

中文翻译：

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用于体内骨重塑应用的植入式电磁微流泵

已经发现骨髓腔内的流体流动的调节刺激骨细胞活动并促进骨生长。然而，流体调制功效的研究仅限于通过皮肤管连接到骨髓腔的外部注射泵。我们报告了一种适用于啮齿动物体内研究的植入式磁性微流泵。使用一组不锈钢模具，在聚二甲基硅氧烷（PDMS）中制造了带有NdFeB磁体的紧凑型微流体泵（直径22毫米，厚度5毫米）。具有更大磁体的外部致动器用于无线致动磁性微流体泵。评估了微流体泵的静态压力随磁体尺寸变化的特性。还对泵的动态压力进行了表征，以估计泵的输出。将电磁微流泵植入Fischer-344大鼠的背部，并使用导管将其连接至股骨的髓腔。发现使用体外执行器进行按需无线电磁操作可在大鼠股骨髓腔内引起高达38 mmHg的压力调制。