CAREER: Investigation of bubble dynamics in microscale geometries, with applications in bioengineering and microfluidics

职业：研究微观几何形状中的气泡动力学，及其在生物工程和微流体学中的应用

• 批准号: 0622862
• 负责人: Daniel Attinger
• 金额: --
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-28 至 2010-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0622862&HistoricalAwards=false
• 关键词: CAREER; Investigation; bubble; dynamics; microscale

ABSTRACT 0449269Investigation of bubble dynamics in microscale geometries, with applications in bioengineering and microfluidics Dynamics phenomena involving microbubbles are aesthetic, complex, and important in industrial applications such as bubble-jet printing. If the dynamics of a bubble in an unbounded liquid is well understood, a lot a basic scientific work needs to be done to understand the dynamics of a bubble in contact with a solid surface, in a bounded microscale geometry. This problem of fundamental and practical interest will be addressed through two research initiatives. The first initiative concerns the dynamic motion of a bubble in a microchannel. The channel geometry, and the dynamic wetting at the gas-liquid-wall interface, control the pressure needed to move the bubble in the channel. This issue is critical in microfluidics devices, where bubbles can clog microchannels with narrow restrictions. This problem will be studied theoretically and experimentally with a MEMS-based setup and high-speed visualization. The second initiative studies how a microbubble attached to a solid surface reacts to ultrasound. Recent investigations have shown that ultrasound drives bubbles oscillations, which produce a tiny, donut-shape vortex in the vicinity of the bubble, a phenomenon called microstreaming. Our theoretical and experimental research will involve simulations of microstreaming in the presence of solid boundaries and Particle-Image-Velocimetry (PIV). This microstreaming field and the associated shear stress will be used to deform biological cells and bring drugs through their membranes, as well as to build a microengine. A general-purpose micro- PIV system will be acquired for this research, with a camera that also allows high-speed imaging. The intellectual merit is the development of a science base for the dynamic behavior of microbubbles in contact with a solid geometry. This first study on the motion of a bubble in a microchannel will be supported on the theoretical side by a collaboration with Henrik Bruus.s research group in Denmark, and on the experimental side (nanocoatings) with Oleg Gang, from the Center for Functional Nanomaterials at Brookhaven National Laboratory. Significant advances are expected on the understanding of the motion of the wetting angle, its hysteresis and relaxation time scale. Our second study will investigate how microstreaming depends on the bubble wetting angle and the nearby solid surfaces. Theoretical and experimental investigations will be performed, involving (for the theoretical side) coupled solid-fluid interactions acoustic calculations, simulations of acoustic microstreaming in the presence of solid boundaries, and (for the experimental side) high-speed visualization together with micro Particle Image Velocimetry. This second study involve collaboration with Dr. Citovski.s biology group at Stony Brook, as well as Dr. Moraga from the Center for Multiphase Research at Rensselaer Polytechnic Institute. The broader impact will be the development in collaborations with Seyonic SA and Micronics Inc- of more reliable microfluidic devices, solving the issue of undesired bubbles through self-cleaning channel geometries or bubble traps. Also, novel ways to interact with biological cells through microstreaming will be investigated, with the development of a novel sonoporation device to control drug transfection through cell membranes and manipulate them. The microstreaming flow field will also be used to power a novel type of microengine that fits in a human hair, to be developed in collaboration with Oleg Gang, from the Center for Functional Nanomaterials at Brookhaven National Laboratory. Finally, we are convinced that visualization of bubble-related phenomena provide an attractive path from everyday experience to current scientific challenges involving micro- and nanoscale phenomena. This will be used to interest local high school and elementary school students from the Bronx to engineering, and to generate interest for research in the Stony Brook student community.

微气泡动力学研究及其在生物工程和微流体学中的应用微气泡的动力学现象是美学的、复杂的，在诸如气泡喷墨打印等工业应用中具有重要意义。如果要很好地理解无界液体中气泡的动力学，就需要做很多基本的科学工作来理解气泡在有界微尺度几何图形中与固体表面接触的动力学。这一具有根本和实际意义的问题将通过两项研究举措加以解决。第一项倡议涉及微通道中气泡的动态运动。通道的几何形状和气液壁界面上的动态润湿控制着移动通道中气泡所需的压力。这一问题在微流控设备中至关重要，因为气泡可以在狭窄的限制下堵塞微通道。这一问题将通过基于MEMS的设置和高速可视化从理论和实验上进行研究。第二项研究是研究附着在固体表面的微泡对超声波的反应。最近的研究表明，超声波驱动气泡振荡，在气泡附近产生一个微小的环状涡流，这种现象被称为微流。我们的理论和实验研究将包括固体边界微流的模拟和粒子图像测速(PIV)。这种微流动场和相关的剪切力将被用来使生物细胞变形，并将药物带入它们的膜中，以及制造微型发动机。为了这项研究，将获得一个通用的微型PIV系统，带有一个也可以进行高速成像的相机。智力上的价值在于为微气泡与固体几何形状接触的动态行为建立了科学基础。这项关于微通道中气泡运动的第一项研究将得到与丹麦亨里克·布鲁斯的研究小组在理论方面的支持，以及与布鲁克海文国家实验室功能纳米材料中心的奥列格·冈在实验方面(纳米涂层)的合作。对于润湿角的运动、润湿角的滞后和松弛时间尺度的理解可望取得重大进展。我们的第二个研究将调查微流如何依赖于气泡润湿角和附近的固体表面。将进行理论和实验研究，包括(对于理论方面)固-液耦合声学计算、存在固体边界时的声学微流模拟以及(对于实验方面)结合微粒子图像测速技术的高速可视化。第二项研究涉及与石溪大学奇托夫斯基博士的生物学团队以及伦斯勒理工学院多阶段研究中心的莫拉加博士的合作。更广泛的影响将是与Seyonic SA和Micronics Inc.合作开发更可靠的微流体设备，通过自清洁通道几何形状或气泡捕集器解决不需要的气泡问题。此外，还将研究通过微流与生物细胞相互作用的新方法，开发一种新型的声波操作设备，以控制药物通过细胞膜的转移并对其进行操作。微流场还将用于为一种新型的微型发动机提供动力，这种微型发动机适合人类头发，将与布鲁克海文国家实验室功能纳米材料中心的奥列格·冈合作开发。最后，我们相信，气泡相关现象的可视化提供了一条诱人的途径，从日常经验到当前涉及微米和纳米现象的科学挑战。这将被用来引起从布朗克斯到工程学的当地高中生和小学生的兴趣，并产生对石溪学生社区的研究兴趣。