Fabrication of microneedles for skin interstitial fluid extraction for allergy testing

传统的不锈钢针在经皮给药、皮肤液体和血液提取等方面给患者带来疼痛，并且在医疗现场测试领域难以与其他医疗设备集成。解决这些限制的一种方法是微针阵列，因为它的侵入面积/深度最小，造成的疼痛更少，并且能够与其他微设备集成。此外，到目前为止还没有微针感染病例的报告。这种微针可以是实心的，也可以是空心的，长度约为500-1200微米，外径不超过300微米。支持公司ExVivo实验室正在开拓新的点护理医疗技术筛选过敏。过敏是一个普遍存在的问题，影响着加拿大和美国大约6000万人。据估计，美国用于治疗过敏性鼻炎的医疗费用几乎翻了一番，从2000年的61亿美元（以2005年的美元计算）增加到2005年的112亿美元，对社会构成了巨大且不断增加的经济负担。ExVivo实验室的目标是减少急诊次数，减少数百万人的旷工率，以及减少过敏的总成本。它的过敏测试贴片是基于使用微针阵列提取疾病指示生物标志物，如免疫球蛋白e (IgE)，它介导I型超敏反应，即过敏。在这个CRD项目中，我们的目标是利用MEMS微加工技术，特别是光刻和深硅蚀刻技术，制造中空硅和聚合物，面外和面内微针阵列。制造的针头随后将通过各向同性干和/或湿蚀刻将其锐化到10微米以下，以便无痛插入皮肤。

For transdermal drug delivery, skin fluid and blood extraction, the conventional stainless steel needle causes pain to the patients and is hard to be integrated with other medical devices at point-of-care-test fields. One solution to those limitations is micro-needle array because of its minimal invasive area/depth causing less pain, and ability to be integrated with other micro-devices. Moreover, no cases of infection by micro-needles have been reported so far. Such micro-needles can be solid or hollow with an approximate length of 500-1200 um and an external diameter of not more than 300 µm.The supporting company ExVivo Labs is pioneering novel point-of-care medical technologies for screening allergies. Allergies are a pervasive problem affecting approximately 60 million people in Canada and the United States. It is estimated that medical expenditures to treat allergic rhinitis in the U.S. almost doubled from $6.1 billion in 2000 (in 2005 dollars) to $11.2 billion in 2005, representing a significant and increasing economic burden to society. ExVivo Labs targets to reduce the number of emergency visits to the hospital, workplace absenteeism for millions of people, and overall cost of allergies. Its allergy test patches are based onextraction using micro-needle array of disease-indicating biomarkers, such as immunoglobulin-E (IgE), which mediates type I hypersensitivity reactions, known as allergies. In this CRD project, we aim to fabricate hollow silicon and polymer, out-of-plane and in-plane, micro-needle array using MEMS microfabrication techniques, notably photolithography and deep silicon etching. The fabricated needles will be subsequently sharpened to under 10 micrometers by isotropic dry and/or wet etching, for painless insertion into skin.