Electro-Optical Platform for the Manipulation of Live Cells

Abstract

The advent of the genome facilitated by the advances in micro-and nanotechnology has revolutionized our understanding of living systems. DNA microarrays, catalytic RNA arrays, and protein arrays are all a consequence of innovations in engineering at the micro-and nanoscales. Here, we extend this paradigm to the fabrication of live mammalian cell arrays that can be used to investigate the state of the cell at the level of an integrated system. Specifically, we describe an electro-optical system that utilizes physical properties of mammalian cells (charge, dielectric permittivity) rather than receptor-mediated adhesion to rapidly pattern and manipulate cells in a microarray format. The platform we describe is an electro-optical method that employs two complementary methods of cell manipulation: (1) electrophoretic arraying of cells in a dc field due to their intrinsic negative surface charge and (2) remote optical manipulation of individual cells by vertical-cavity surface emitting laser driven infrared optical tweezers. The platform is optically transparent and thus enables monitoring of fluorescent reporters of cellular events (e.g., expression of green fluorescent protein) and allows remote optical manipulation of arrayed cells without risk of breaching the aseptic environment. In addition to the experimental manipulation of mammalian cells, we also present a theoretical framework to establish the limitations of the platform we describe. The ability to probe dynamic cellular events in parallel may offer insights into unforeseen biological mechanisms of cellular function and find applications in drug discovery, functional genomics, and tissue engineering.

Blood-on-a-Chip

“…Vertical-cavity surface emitting laser-driven infrared optical tweezers were used for remote manipulation of individual cells arrayed using direct current electrophoresis (91). The laser can also remove selected cells from their locations on the array (79), either by capture microdissection (92) or laser catapulting (93,94).…”

“…Combinations of electrical and optical methods for cell manipulation have also been demonstrated. Direct current electrophoresis has been used to position negatively charged mammalian cells in array formats, and optical tweezers subsequently used to move cells (91).…”

Exploitation of physical and chemical constraints for three-dimensional microtissue construction in microfluidics

“…A microfluidic system can improve such tissue culture to control the culture microenvironment more precisely. In fact, the combination of optical tweezers and microfluidics had been used for single cell trapping and manipulating, 118,119 cell guiding, 120 cell sorting, [121][122][123] and biological particles analysis. 124,125 The single-beam optical tweezers require a separate laser beam for each manipulation object.…”

“…For example, VCSEL array optical tweezers have been used for parallel trapping of yeast cells, 131 red blood cells, 131 and neuronal cells. 118 More interestingly, studies have shown the ability to create complex biofilm or tissue structures in a microfluidic system in conjunction with optical trap arrays. In Mirsaidov's work, 132 E.coli labeled with either green fluorescence protein or red fluorescence protein were delivered from two separate microfluidic channels.…”

Quantifying the effect of electric current on cell adhesion studied by single-cell force spectroscopy

“…This effect can be reduced or completely avoided by using alternating currents 18 or pulsed direct currents. 19,20 Constant electric fields cannot penetrate the cell membrane due to its high resistance, but they can trigger molecular signaling pathways at the cell surface by activating voltage-gated calcium channels, plasma membrane receptors, or stretch-activated cation channels.…”