A Microfluidic System with Surface Patterning for Investigating Cavitation Bubble(s)&#8211;Cell Interaction and the Resultant Bioeffects at the Single-cell Level

Fenfang Li; Fang Yuan; Georgy Sankin; Chen Yang; Pei Zhong

doi:10.3791/55106

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Method Article

A Microfluidic System with Surface Patterning for Investigating Cavitation Bubble(s)–Cell Interaction and the Resultant Bioeffects at the Single-cell Level

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DOI:

10.3791/55106

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January 10th, 2017

Fenfang Li¹ , Fang Yuan² , Georgy Sankin¹ , Chen Yang¹ , Pei Zhong¹

¹Mechanical Engineering and Materials Science, Duke University, ²Huacells Corp

Summary

A microfluidic chip was fabricated to produce pairs of gold dots for tandem bubble generation and fibronectin-coated islands for single-cell patterning nearby. The resultant flow field was characterized by particle image velocimetry and was employed to study various bioeffects, including cell membrane poration, membrane deformation, and intracellular calcium response.

Abstract

In this manuscript, we first describe the fabrication protocol of a microfluidic chip, with gold dots and fibronectin-coated regions on the same glass substrate, that precisely controls the generation of tandem bubbles and individual cells patterned nearby with well-defined locations and shapes. We then demonstrate the generation of tandem bubbles by using two pulsed lasers illuminating a pair of gold dots with a few-microsecond time delay. We visualize the bubble-bubble interaction and jet formation by high-speed imaging and characterize the resultant flow field using particle image velocimetry (PIV). Finally, we present some applications of this technique for single cell analysis, including cell membrane poration with macromolecule uptake, localized membrane deformation determined by the displacements of attached integrin-binding beads, and intracellular calcium response from ratiometric imaging. Our results show that a fast and directional jetting flow is produced by the tandem bubble interaction, which can impose a highly localized shear stress on the surface of a cell grown in close proximity. Furthermore, different bioeffects can be induced by altering the strength of the jetting flow by adjusting the standoff distance from the cell to the tandem bubbles.

Introduction

There is a growing recognition that cellular heterogeneity, arising from the stochastic expression of genes, proteins, and metabolites, exists within a large cell population and serves as a fundamental principle in biology to allow for cell adaptation and evolution¹. Therefore, it is often inaccurate and unreliable to use population-based bulk measurements to understand the function of individual cells and their interactions. Developing new technologies for single-cell analysis is therefore of high interest in biological and pharmacological research, and can be used, for example, to better understand the key signaling pathways and processes in stem cell bio....