Integrated MEMS microneedles and microelectrode arrays for biomedical applications

皮下注射针有许多缺点，例如插入疼痛、组织创伤以及执行注射所需的专业知识。针头阵列通过只穿透皮肤的上部，避免神经，有望实现无痛提取和输液。空心和实心微针是两种最常见的设计。空心微针的工作原理与其较大的对应物一样，液体流过一根管子刺穿皮肤。然而，它们可能遭受开口的堵塞并且有可能破裂。固体微针涂有治疗剂，允许药物分子溶解到周围组织中。剂量取决于微针面积，因此产量有限。 这项工作将研究新的中空微针设计和材料，以克服堵塞问题并提高耐用性。为了克服固体微针的产量问题，将探索新的设计，例如在固体微针的基部附近创建微流体通道，以使相关量的药物能够通过刺穿的组织递送。 微制造方法是制造微针阵列的理想方法，因为材料具有生物相容性，坚固耐用，并且设计用于与其他微制造工艺进行大规模集成。将微针与合适的微泵送方法集成将使得能够开发紧凑的药物递送或流体提取系统。 血液等生理流体含有许多生物颗粒，并造成困难，因为它们可能堵塞微流体系统，机械泵送方法产生的剪切力可能损坏细胞。为了应对这些挑战，将研究称为电动微泵的非机械微泵方法。流体通过电场移动，因此没有移动部件，如阀门或膜，供颗粒粘附或损坏。电动系统本身也更容易通过数字电子设备进行控制，使其成为与微控制器集成的理想选择，从而能够精确控制微针系统中的流体流动。 这项研究将从实验室转移到床边，通过集成微针和微泵来创建一个无需直接医疗干预即可使用的微针系统。为此，我们将重点实现三个具体目标： 1)新型空心和实心微针的开发 2)电动微泵的研究进展 3)创建集成微针系统。 这项工作支持的多样化HQP将学习尖端的微加工和模拟技术。他们将通过设计、制造和测试微针系统来验证他们的想法。与过去的HQP一样，该计划将为他们未来在生物医学行业和学术界的就业做好准备。这项研究将导致药物输送的新技术，提高患者的生活质量，并通过减少医疗保健支出使经济受益。

There are many drawbacks to hypodermic needles, such as insertion pain, tissue trauma, and expertise needed to perform an injection. Microneedle arrays promise potentially painless extraction and infusion by penetrating only the upper part of the skin, avoiding the nerves. Hollow and solid microneedles are the two most common designs. Hollow microneedles work as their larger counterparts, with fluid flow through a tube piercing the skin. However they can suffer from clogging of the opening and have the potential to break. Solid microneedles are coated with a therapeutic agent, allowing drug molecules to dissolve into the surrounding tissue. The dosage depends on the microneedle area and therefore the yield is limited. This work will investigate new hollow microneedle designs and materials to overcome clogging issues and improve robustness.. To overcome the solid microneedle yield issue, new designs will be explored, such as the creation of microfluidic channels next to the base of the solid microneedles, to enable delivery of relevant amounts of drugs through the pierced tissue. Microfabrication methods are ideal to create microneedle arrays, as the materials are biocompatible, robust and designed for large-scale integration with other micro manufacturing processes. Integrating microneedles with suitable micropumping methods will enable a compact drug delivery or fluid extraction system to be developed. Physiological fluids such as blood contain many bio particles and pose difficulties as they can clog microfluidic systems and shear forces from mechanical pumping methods can damage cells. To tackle these challenges, non-mechanical micropumping methods known as electrokinetic micropumping will be investigated. Fluid is moved via electric fields and thus there are no moving parts, like a valve or membrane, for particles to adhere to or be damaged by. Electrokinetic systems are also inherently easier to control via digital electronics, making them ideal for integration with a microcontroller, enabling precise control of fluid flow in the microneedle system. This research will move from the bench to the bedside, by integrating microneedles and micropumps to create a microneedle system that can be used without direct medical intervention. We will achieve this by focusing on three specific aims: 1) Development of new hollow and solid microneedles 2) Development of electrokinetic micropumps 3) Creation of integrated microneedle systems. The diverse HQP supported by this work will learn cutting-edge microfabrication and simulation techniques. They will validate their ideas by designing, fabricating and testing microneedle systems. As with past HQP, this program will prepare them for future employment in the biomedical industry and academia. This research will lead to new technologies for drug delivery, improving quality of life for patients and benefitting the economy through reducing healthcare expenditures.