Development of handheld microfluidic breath-analyzer to detect tetrahydrocannabinol and other target volatile organic compounds

近几十年来，由于人们对其药用价值的认识不断加深，以及公众对娱乐用途合法化的支持不断增加，对大麻的看法发生了变化。通常，大麻的使用分为两类，药用者寻求减轻其疾病的症状，而娱乐性使用者则希望获得欣快感。因此，精神活性化学物质（例如，血液中的四氢大麻酚（THC））可能取决于使用者的类型，这是测试损伤时的一个重要区别。目前的技术集中在血液和唾液样本上，由于侵入性样本收集或准确性差，这是不利的。呼吸分析是一种很有前途的替代方案，因为它既无创，又由于呼吸中THC的浓度与血液中的水平密切匹配，因此它可以提供准确的结果。然而，呼吸分析有许多挑战，包括控制湿度和区分呼出气体中的化学物质。我们的技术将金属氧化物半导体与特定几何形状和涂层的微流体通道配对;这提供了一种高度灵敏和选择性的检测方法，比传统方法（如气相色谱法）更便携。我们将开发一种用于监测呼吸中THC的解决方案，其目标如下：（1）改善现有气体传感器技术的响应时间，（2）控制信号干扰（例如，湿度），（3）开发用于样本收集的盒，（4）使用机器学习来根据人类呼吸校准设备，（5）将传感器封装在加固便携式装置中，以及（6）与行业合作伙伴合作验证原型并将呼吸样本与THC的血浆浓度相关联。最终，这项技术不仅将提供一种非侵入性工具，使大麻使用者能够更多地了解他们的暴露水平，而且还可以作为一种筛选工具，帮助在工作场所和执法部门执行指定的暴露限制。这意味着个人对他们的大麻摄入量有了更好的了解，道路和工作环境更安全，并且有了一个新的工具来研究THC引起的损害的复杂性。

Perspectives on cannabis have shifted in recent decades due to increased understanding of its medicinal qualities and mounting public support for legalization of recreational use. Typically, cannabis use is separated into two categories, with medicinal users seeking to reduce symptoms of their ailment and recreational users desiring euphoric effects. Consequently, the amount of psychoactive chemicals (e.g., tetrahydrocannabinol (THC)) in the blood stream can depend on the type of user, which is an important distinction when testing for impairment. Current technology focuses on blood and saliva samples, which are unfavourable due to either invasive sample collection or poor accuracy. Breath analysis is a promising alternative as it is both non-invasive and, since the concentration of THC in breath closely matches the levels present in blood, it provides accurate results. However, breath analysis has many challenges, including controlling for humidity and discriminating between chemicals in exhaled breath. Our technology pairs a metal-oxide semiconductor with a microfluidic channel of specific geometry and coatings; this provides a highly sensitive and selective method of detection that is much more portable than conventional methods, such as gas chromatography. We will develop a solution for monitoring THC in breath in the following objectives: (1) improve response time of existing gas sensor technology, (2) control for signal interference (e.g., humidity), (3) develop cartridges for sample collection, (4) use machine learning to calibrate device to human breath, (5) package sensor within a ruggedized portable setup, and (6) validate prototype and correlate breath samples to plasma concentration of THC in collaboration with industry partners. Ultimately, this technology will not only provide a non-invasive tool that allows cannabis users to be more aware about their level of exposure but can also be packaged to serve as a screening tool to help enforce designated exposure limits in workplaces and by law enforcement. This translates into individuals having a better understanding of their cannabis intake, safer roads and work environments, as well as having a new tool to study the complexity of THC-induced impairment.