Collaborative Research: Magnetically Actuated Black Silicon Ratchet Surfaces for Digital Microfluidics

合作研究：用于数字微流体的磁驱动黑硅棘轮表面

• 批准号: 1950009
• 负责人: Placid Ferreira
• 金额: $ 31.05万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1950009&HistoricalAwards=false
• 关键词: Collaborative; Research; Magnetically; Actuated; Black

Since most of the sensitive and standardized bio-analytical techniques work in the liquid medium, the lab-on-a-chip system should be able to efficiently handle liquid solutions in micro/nano scale. To date, most of these systems have been developed based on the continuous flow system which lacks device reconfigurability. Consequently, much attention has been drawn to droplet-based lab-on-a-chip systems, namely, digital micro fluidic systems based on electrowetting that manipulate discrete liquid droplets rather than continuous liquid streams. Nevertheless, the electrowetting-based approach suffers from limitations such as high voltage requirement and biofouling, hampering many real applications. This project provides a straightforward pathway to a new digital micro fluidic platform without electrowetting-related limitations. The proposed platform exploits a purely mechanical means to drive discrete liquid droplets in a rapid, flexible, programmable, and reconfigurable manner. This project will also generate information and demonstration materials that can be directly used to promote both classroom teaching and general public's interest in materials, microfluidics, interfacial science, micro/nanotechnology. The project aims to explore the dynamically tunable surface morphology and consequential interfacial wettability using a black silicon ratchet surface in order to seek a new strategy to manipulate liquid droplets for the advancement of digital microfluidics. The proposed ratchet surface involves superhydrophobic black silicon scales on elastomer micropillars such that individual signals actuate individual scales and change the entire surface morphology forming a black silicon ratchet surface that drives liquid droplets. Consequently, droplets are essentially driven mechanically, not electrically. In addition, it is expected that conical nanostructures on the black silicon surface and/or slippery liquid infused porous surfaces to be integrated will significantly reduce biofouling. The proposed approach cannot be realized without elucidating underlying principles and establishing necessary techniques. Two principal investigators’ expertise encompassing mechanics, materials, manufacturing and microfluidics will be combined in order to achieve those understanding and knowledge, and finally open up a new interdisciplinary research area across smart composite materials and digital microfluidics. During the project, three objectives will be systematically pursued to towards the project goal. First, the mechanical characteristics involved in the proposed superhydrophobic ratchet surface will examined, Second, the interaction between liquid droplets and the superhydrophobic ratchet surface will be characterized and associated forces to manipulate liquid droplets on it will be investigated. Finally, droplet manipulations including droplet transporting, merging, and splitting along with the reduced biofouling will be demonstrated.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.

由于大多数敏感且标准化的生物分析技术都在液体介质中工作，因此芯片实验室系统应该能够有效地处理微/纳米尺度的液体溶液。迄今为止，大多数此类系统已经开发出来。基于缺乏设备可重构性的连续流系统，基于液滴的芯片实验室系统受到了很多关注，即基于电润湿的数字微流体系统，其操纵离散的液滴而不是连续的液流。尽管如此，.基于电润湿的方法受到高电压要求和生物污垢等限制，阻碍了许多实际应用，该项目提供了一种没有电润湿相关限制的新型数字微流体平台的直接途径。该项目还将生成可直接用于促进课堂教学和公众对材料、微流体、界面的兴趣的信息和演示材料。该项目旨在利用黑硅棘轮表面探索动态可调的表面形态和相应的界面润湿性，以寻求一种操纵液滴的新策略，以促进数字微流体的发展。弹性体微柱上的黑硅鳞片，使得单个信号驱动单个鳞片并改变所检查的整个表面形态，形成驱动液滴的黑硅棘轮表面。此外，预计黑硅表面和/或光滑液体注入多孔表面上的锥形纳米结构将显着减少生物污垢，除非阐明基本原理并建立。两位主要研究人员将结合力学、材料、制造和微流体学的专业知识，以实现这些理解和知识，并最终开辟一个跨越智能复合材料和数字微流体学的新的跨学科研究领域。在该项目期间，最终将实现三个目标：首先，将检查所提出的超疏水棘轮表面所涉及的机械特性；其次，将表征液滴与超疏水棘轮表面之间的相互作用以及相关力。最后，将演示液滴操纵，包括液滴传输、合并和分裂以及减少生物污垢。该奖项反映了 NSF 的法定使命，并通过评估被认为值得支持。利用基金会的智力优势和更广泛的影响审查标准。