EAPSI: Designing Microfluidic Tools with Applications in the Development of Small Molecule Detection Sensors

小分子的检测和定量对于基础生物和环境研究、药物开发和临床实践具有重要意义。基于寡核苷酸的传感器为检测小分子提供了强有力的选择，但由于难以将潜在的传感器分子从惰性物种中分离出来，这些传感器的发展一直受到阻碍。基于液滴的微流控技术是解决这些问题的独特之处；这些技术允许分离和处理单个传感器分子和小分子目标。该项目将侧重于设计和表征一种产生液滴的微流控装置，其效率和功能比现有装置更高。这项研究是与新加坡国立大学基于液滴的微流体专家赛义夫·汗博士合作完成的。适配子是一种具有高亲和力和高特异性结合靶标的短寡核苷酸，是一种很有前途的小分子检测新工具，可以克服目前基于抗体的传感器存在的问题，即生产成本高，热稳定性和生化稳定性低。然而，由于从大的起始寡核苷酸文库中分离候选适配子的问题，用于小分子靶标的适配子的开发还没有完全放大。基于液滴的微流体可以用来克服分配问题，因为油包水液滴为在适配子开发过程的扩增和选择阶段分离和处理单个寡核苷酸提供了一个平台。为了使微流控设备成为适配子开发过程的可行工具，这些设备需要非常高的液滴生成率。该项目旨在提高可汗实验室开发的3D微流控液滴发生器的液滴生成率。该项目还将探索通道尺寸、连续相组成以及连续相和分散相之间的流量比如何影响液滴直径和热稳定性。该奖项由东亚和太平洋夏季学院项目资助一名美国研究生进行的夏季研究，由NSF和新加坡国家研究基金会共同资助。

The detection and quantification of small molecules is of great importance to fundamental biological and environmental research, pharmaceutical development, and clinical practice. Oligonucleotide-based sensors provide a robust and powerful option for the detection of small molecules, but the development of these sensors has been hindered by the difficulty of separating potential sensor molecules from inert species. Droplet-based microfluidic technologies are uniquely situated to address these issues; these technologies allow for the separation and handling of individual sensor molecules and small molecule targets. This project will focus on the design and characterization of a droplet-generating microfluidic device with improved efficiencies and functionality over existing devices. This research is being done in collaboration with Dr. Saif Khan, an expert in droplet-based microfluidics, at the National University of Singapore. Aptamers, short oligonucleotides that bind targets with high affinity and specificity, are promising new tools for small molecule detection that overcome problems with current antibody based sensors, namely high production costs and low thermal and biochemical stability. However, the development of aptamers for small molecule targets has not been fully scaled up due to issues with partitioning aptamer candidates from large starting libraries of oligonucleotides. Droplet-based microfluidics can be utilized to overcome the partitioning issues as water-in-oil droplets provide a platform for the separation and handling of single oligonucleotides at both the amplification and selection stages during the aptamer development process. In order for microfluidic devices to be a viable tool for the aptamer development process, the devices require very high rates of droplet generation. The project aims to improve the rate of droplet generation of the 3D microfluidic droplet generators developed in the Khan lab. The project will also explore how channel dimensions, continuous phase composition, and the flowrate ratio between continuous phase and dispersed phase affect droplet diameter and thermal stability.This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the National Research Foundation of Singapore.