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Abstract

Studying cell functions for cellomics studies often requires the use of purified individual cells from mixtures of various kinds of cells. We have developed a new non-destructive on-chip cell sorting system for single cell based cultivation, by exploiting the advantage of microfluidics and electrostatic force. The system consists of the following two parts: a cell sorting chip made of polydimethylsiloxane (PDMS) on a 0.2-mm-thick glass slide, and an image analysis system with a phasecontrast/fluorescence microscope. The unique features of our system include (i) identification of a target from sample cells is achieved by comparison of the 0.2-µm-resolution phase-contrast and fluorescence images of cells in the microchannel every 1/30 s; (ii) non-destructive sorting of target cells in a laminar flow by application of electrostatic repulsion force for removing unrequited cells from the one laminar flow to the other; (iii) the use of agar gel for electrodes in order to minimize the effect on cells by electrochemical reactions of electrodes, and (iv) pre-filter, which was fabricated within the channel for removal of dust contained in a sample solution from tissue extracts. The sorting chip is capable of continuous operation and we have purified more than ten thousand cells for cultivation without damaging them. Our design has proved to be very efficient and suitable for the routine use in cell purification experiments.

An on-chip imaging droplet-sorting system: a real-time shape recognition method to screen target cells in droplets with single cell resolution

“…In comparison with conventional electrodes reported in the literature, the advantages of the saline solution in the electrode channels are: ( i ) the absence of contact between the main channel and electrodes1921; ( ii ) conducting direct current (DC) pulses of high voltage (up to 1,500 V) without any damage observable on the electrode44; ( iii ) creating the electrode channel using a conventional chip fabrication protocol45; ( iv ) the cost of saline preparation is cheaper than low melting temperature metal alloy or micro–nanoparticles of metal946; ( v ) setting and filling processes of the four electrodes can be performed in less than 5 min prior to analysis. The main disadvantage of the saline solution liquid electrodes compared with agarose liquid electrodes is the possible formation of microscopic NaCl crystals in the electrode channels in the case of long experiments or drying by Joule heat.…”

Microfluidic Sample Preparation for Single Cell Analysis

“…43 This separation mode is termed electrophoresis (EP) (Figure 4A). Takahashi et al 44 designed a device in which two laminar flow streams converge at the center of the device. Cells are introduced in one stream and imaged every 1/30 th of a second as they pass the convergence point.…”

Non-destructive on-chip imaging flow cell-sorting system for on-chip cellomics

“…We tested two previously reported types of cell-sorting chips made of PMMA-based plastic (Hayashi et al 2011a;Hattori et al 2011;Takahashi et al 2004): a two-way outlet chip ( Fig. 4a-c) and a three-way-outlet chip ( Fig.…”