Microneedle Array for Catheter Drug Delivery

描述(由申请人提供)：该项目的最终目标是开发一种可以直接将药物注入冠状动脉壁以防止血管成形术后再狭窄的导管。微电子机械系统(MEMS)技术将被用来从硅衬底制作微型中空针的原型。微针阵列将与低轮廓导管输送系统集成在一起，用于往返于动脉内的部署地点。有限元建模将被用来产生坚固的针形设计，随后将使用硅的深度反应离子刻蚀和湿法各向异性刻蚀来制造针形设计。将制造不同的微针几何形状和阵列布局，并评估其机械强度和对填充的兔、丁香和猪冠状动脉的穿透特性。将开发两个低轮廓导管输送系统，将微针阵列输送到冠状动脉。一种方法将依靠一个低调的气球将微针阵列容纳在气球内的模制口袋中。另一种方法将研究一种新型的吸管，它将在运输过程中容纳微针。一旦到达动脉内的部署位置，就会通过注射器进行抽吸，将血管壁拉向导管，并迫使微针进入组织。液体输送将通过将埃文的蓝色染料注射到动脉壁来演示。将进行实验和计算机建模，以优化微针的几何形状和阵列布局，以实现穿透和流体输送。R21项目的结果将为进一步开发用于局部给药导管的微针奠定可行性，该微针可用于研究直接进入血管壁的抗再狭窄治疗的疗效和给药特点。

DESCRIPTION (provided by applicant): The ultimate goal of this project is the development of a catheter that can inject drugs directly into the wall of the coronary artery to prevent restenosis after angioplasty. MEMS (microelectromechanical systems) technology will be used to prototype miniature hollow needles from silicon substrates. Microneedle arrays will be integrated with low profile catheter delivery systems for transport to and from the deployment site within arteries. Finite element modeling will be used to generate robust needle designs, which will be subsequently fabricated using deep reactive ion etching and wet anisotropic etching of silicon. Different microneedle geometries and array layouts will be fabricated and evaluated for mechanical strength and penetration characteristics into filleted rabbit lilac and porcine coronary arteries. Two low profile catheter delivery systems will be developed to transport the microneedle array to the coronary artery. One approach will rely on a low profile balloon to house the microneedle array inside molded pockets within the balloon. The other approach will investigate a novel suction catheter that would house the microneedle during transport. Once at the deployment site within the artery, suction would be applied via a syringe to pull the vascular wall towards the catheter and force the microneedles into the tissue. Fluid delivery will be demonstrated by injecting Evan's Blue dye into the arterial wall. Experiments and computer modeling will be conducted to optimize the microneedle geometry and array layout for penetration and fluid delivery. Results of this R21 project will establish the feasibility for further development of microneedles for local drug delivery catheters that could be used to investigate the efficacy and delivery characteristics of anti-restenosis therapy delivered directly into the vascular wall.