Microfluidic Chain Reaction: Exploration, Expansion, and Application

微流控链式反应：探索、扩展和应用超灵敏免疫分析揭示了迄今为止无法检测到的特征，并有望推进COVID 19、HIV、神经系统疾病和损伤以及癌症的早期诊断和监测。它们的影响在护理点（POC）最大，但它们仍然依赖于实验室中的复杂仪器，并受到检测性能和获得结果时间之间的权衡的抑制。 我们建议研究和开发两个实验室发现：微流控链式反应（MCR）和布朗亲和阱（BAT）阵列，并将它们集成在3D打印的毛细管微流控芯片上，用于最小仪器化，超灵敏（zeptomolar）和快速（<30分钟）POC测试。我们之前介绍了毛细管回路（CC），其使用毛细管现象来（i）执行多达8个在表面微架构中结构编码的流体操作，以及（ii）用于泵送。我们最近发现了MCR，它引入了有条件的、基于事件的可编程性（即链式反应），并使MCR-CC能够编码和自主执行以前需要计算机的复杂算法（300步）。BAT是一种涂有抗体的微孔，由于布朗运动引起的壁碰撞和亲和结合，它捕获流过其中的靶分子。 总体目标是探索MCR和BAT，并将其联合收割机用于最小仪器化、超灵敏、快速的POC测试。 目标1：MCR勘探、扩展和补充CC和MCR限于高表面张力水溶液，其可以“解码”结构编码的流体操作。我们建议将CC扩展到低表面张力液体，使用水溶液的间接阀门和3D打印毛细管“超级”阀门。利用负压实现MCR。我们将设计正压MCR和互补n-p MCR。我们将在MCR-CC中编码DNA提取和药物筛选，作为概念验证。目标二：布朗亲和阱（BAT）及其用于数字ELISA的用途超灵敏数字ELISA（dELISA）使用珠包封，并且每个珠被读出为“0”，或者在单分子结合的情况下读出为“1”。我们将通过计算和实验来研究BAT。样品将流过数百万个BAT的阵列，并检测单分子结合事件。我们预测BAT dELISA将更加灵敏和快速。目标3：用于POC诊断的MCR和BAT的数字增材制造MCR可以很容易地进行3D打印，但具有疏水性。我们为MCR-CC的直接（即数字化）制造推出了新型亲水树脂（包括BAT），用于与合作者的分布式制造。 MCR-CC对微流体的意义可能就像手机（便携式计算机）对台式计算机一样，而它们可以使用500美元的3D打印机在家中制造，并用于进行超灵敏，快速，护理点诊断。

Microfluidic Chain Reaction: Exploration, Expansion, and Application Ultrasensitive immunoassays reveal hitherto undetectable features, and are poised to advance early diagnosis and monitoring of COVID19, HIV, neurological disease and injury, and cancer. Their impact would be greatest at the point-of-care (POC), but they remain dependent on complex instrumentation housed in laboratories, and are stifled by a trade-off between assay performance and time-to-result. We propose to study and develop two lab discoveries: Microfluidic chain reactions (MCRs) and Brownian affinity trap (BAT) arrays, and integrate them on 3D printed capillary microfluidic chips for minimally instrumented, ultrasensitive (zeptomolar), and fast (<30 min) POC testing. We previously introduced capillaric circuits (CCs) that use capillary phenomena to (i) execute up to 8 fluidic operations structurally encoded in the surface microarchitecture, and (ii) for pumping. We recently discovered MCR that introduce conditional, event-based programmability (i.e. chain reaction), and enable MCR-CCs to encode, and autonomously execute, complex algorithms (300 steps) previously requiring a computer. The BAT is a microscopic pore coated with antibodies, and traps target molecules flowing through it because of Brownian motion induced wall collisions and affinity binding. The Overall goal is to explore the MCR and the BAT, and combine them for a minimally instrumented, ultrasensitive, rapid, POC test. Aim 1: MCR Exploration, Extension and Complementation CCs and the MCR are restricted to high surface tension aqueous solutions that can `decode' the structurally encoded fluidic operations. We propose to extend CCs to low surface tensions liquids using indirect valving with aqueous solutions, and 3D printed capillary `super' valves. MCR was realized using negative pressure. We will design positive pressure MCR, and complementary n-p MCR. We will encode DNA extraction and drug screening in MCR-CCs as a proof-of-concept. Aim 2: The Brownian Affinity Trap (BAT) and its use for digital ELISA Ultrasensitive digital ELISA (dELISA) use bead encapsulation, and each bead is read out as a "0", or in case of single molecule binding a "1". We will study computationally and experimentally the BAT. Samples will be flowed through arrays of millions of BATs, and single molecule binding events detected. We predict that BAT dELISA will be more sensitive and much faster. Aim 3: Digital additive manufacturing of MCRs and BATs for POC diagnostics MCRs can readily be 3D printed, but are hydrophobic. We introduce new hydrophilic resins for direct (i.e. digital) manufacturing of MCR-CCs (incl. BATs), for distributed manufacturing with collaborators. Significance MCR-CCs could become to microfluidics what cell phones (portable computers) are to desktop computers, while they could be home-built using a $500 3D printer, and used to make ultrasensitive, rapid, point-of-care diagnostics thanks to BAT arrays.