Microneedle fabrication and applications

微纳科学技术是近年来发展最快的研究领域之一。除了传统的半导体行业，使用洁净室设施的微纳制造技术也广泛应用于包括微机电系统、显示器、光伏、数据存储、生物医学传感器和光通信等行业。在本研究项目中，将利用洁净室设备的自顶向下微加工技术来制造微针器件。微针技术已成为实现能够经皮给药和体液采样和诊断的微创平台的有利条件。微针有望减轻与枪和皮下注射针相关的缺点。它只需要在有限的深度穿透一小块皮肤，导致与疼痛和组织损伤相关的真皮层的最小刺激。本研究项目将重点发展新型空心微针制造技术及其在药物输送和疾病诊断方面的应用。与固体微针相比，空心微针在药物输送方面提供了更好的流体控制。在我们之前资助的Discovery基金中，我们开发了一种（短）空心硅微针的制造工艺，该工艺能够提取间质液进行过敏试验，但由于针头长度有限，重复性较差。然而，对于药物输送，以及在较小程度上用于诊断的间质液的提取，在目标输送部位远低于皮肤表面或皮肤太柔韧或太厚的医疗应用中，需要更高的微针。因此，在接下来的五年里，我们将扩大我们的研究成果，以制造更长（高达1.5毫米，而目前中空硅微针的记录长度约为1毫米）和更尖锐的针头，以及用于通过微针输送药物和提取体液的微流体平台。为实现本研究计划的目标，将探索包括干等离子体刻蚀和晶圆键合在内的尖端微加工技术以及精心设计的制造过程。微针技术在生物传感和药物递送方面具有广泛且不断增长的应用，包括可能无痛（或一些轻微疼痛，取决于针头长度）递送COVID-19疫苗。本研究开发的超长空心微针将成为微针技术的关键推动者。学生将接受设备设计和制造方面的强化实践培训。加拿大许多重要的工业部门可以利用微针技术和微纳米制造技术，这个项目将在这个不断发展的领域创造知识、创新和技术专家。

Micro-nanoscale science and technology has become one of the fastest growing research areas in recent years. Besides the conventional semiconductor industry, micro-nanofabrication techniques using cleanroom facility are also widely employed in industries including microelectromechanical systems, displays, photovoltaics, data storage, biomedical sensors, and optical communications. For this research program, top down microfabrication techniques using cleanroom facility will be utilized to fabricate the microneedle devices. Microneedle technologies have become beneficial for realizing minimally invasive platforms capable of transdermal drug delivery and body fluid sampling and diagnostics. Microneedles are anticipated to mitigate the shortcomings associated with lancets and hypodermic needles. It requires only a small area of skin to be penetrated at a limited depth, resulting in minimal irritation of dermal layers associated with pain and tissue damage. This research program will focus on developing novel hollow microneedle fabrication technology and its future applications for drug delivery and disease diagnosis. Compared to solid microneedles, hollow ones offer much better fluidic control for drug delivery. In our previously funded Discovery grant, we developed a fabrication process for (short) hollow silicon microneedles, which are capable of extraction of interstitial fluid for allergy test, yet with poor reproducibility due to the limited needle length. For drug delivery, and to a less degree, extraction of interstitial fluid for diagnosis, however, taller microneedles are needed for medical applications where the target delivery site is far below the skin surface or the skin is too flexible or too thick. As such, in the next five years, we will expand on our findings to fabricate longer (up to 1.5mm, compared to currently record length of ~1mm for hollow silicon microneedle) and sharper needles, as well as microfluidic platform for drug delivery and extraction of body fluid through microneedle. Cutting edge microfabrication technology including dry plasma etching and wafer bonding and thoughtful design of the fabrication procedure will be explored to realize the objectives for this research program. Microneedle technology has a wide and growing range of applications for bio-sensing and drug delivery including potentially the painless (or some minor pain, depending on needle length) delivery of COVID-19 vaccine. The ultra-long hollow microneedle to be developed in this research will be the key enablers for microneedle technology. Students will receive intensive hands-on training in device design and fabrication. Many industrial sectors of importance to Canada could exploit the microneedle technologies and the micro-nanofabrication techniques, and this program will create knowledge, innovation and technical experts in this growing field.