Enabling Light-Driven Microfluidics with Laser Streaming

微流体学研究的是小体积流体在微通道网络中的流动。微流控装置有可能改变医学和医疗保健等多个领域，从药物输送到癌症治疗。类似于你家里的管道系统，微流体装置的功能依赖于泵和阀门。由于它们的尺寸小，这样的组件是复杂的和昂贵的制造。这被认为是微流体广泛应用的瓶颈。作为一种新的解决方案，光驱动微流体利用光来驱动和控制流动。目前，基于光的方法只适用于特殊类型的流体，甚至不包括水。该项目将创造一种称为激光流的新方法，使微流体中的光驱动方法适用于所有类型的流体。通过这个项目，将为学生提供从K-12到研究生水平的培训机会，为他们未来的STEM职业做好准备。本项目的目标是通过阐明激光流的基础物理，解决光-物质相互作用的可调性，并证明其在微流体操作中的有效性，为激光流奠定科学和技术基础。该项目将侧重于四个具体目标：通过粒子图像测速和声学测量，实验验证了激光流是激光诱导光声学和eckart型声流协同作用的假设；（ii）对涉及光热、热弹性和声流相互作用的多物理过程进行了数值模拟；（三）发展光学方法，利用激光诱导光栅技术调制光声能量转换，优化激光流流的可控性；（四）实验展示激光流在微流体泵浦、混合和阀化操作中的有效性。在实际应用方面，这项工作将使光驱动微流体从其基本限制中解放出来，在众多行业中得到实际应用。在知识方面，该项目将为光声流体学这一新的学科奠定基础，它可能超越传统的光流体学和声流体学，在科学和工程领域创造各种新的机会。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Microfluidics deals with flow of small volumes of fluids in a network of tiny channels. Microfluidic devices have the potential to transform several fields including medicine and healthcare, from drug delivery to cancer treatment. Similar to the piping system in your house, the function of a microfluidic device relies on pumps and valves. Because of their small dimensions, such components are complex and costly to fabricate. This is considered a bottle-neck to the wide-spread use of microfluidics. As a novel solution, light-driven microfluidics uses light to drive and control the flow. At present, the light-based methods only work with special types of fluids that do not even include water. This project will create a new approach, called laser streaming, to make the light-driving method in microfluidics possible for all types of fluids. Through this project, training opportunities will be offered to students, from K-12 to graduate levels, to prepare them for future STEM careers. The goal of this project is to lay the scientific and technological foundation for laser streaming by elucidating the underlying physics, addressing the tunability of light-matter interactions, and demonstrating its efficacy for microfluidic operations. This project will focus on four specific aims: (i) Experimentally validating the hypothesis that laser streaming is the synergy of laser-induced photoacoustics and Eckart-type acoustic streaming with resort to particle image velocimetry and acoustic measurements, (ii) Numerically modeling the multi-physical processes involving photothermal, thermoelastic and acoustic streaming interactions, (iii) Developing optical methods to modulate light-to-sound energy conversion and optimize the controllability of laser streaming flow by using laser-induced grating techniques, and (iv) Experimentally showcasing the efficacy of laser streaming in microfluidic pumping, mixing and valving operations. On the practical aspect, this work will unleash light-driven microfluidics from its fundamental constraints for practical applications in a myriad of industries. On the intellectual aspect, this project will set the cornerstone for a new discipline called opto-acoustofluidics, which may go beyond conventional optofluidics and acoustofluidics to foster various new opportunities in science and engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.