Effect of Electrolyte Concentration on Cell Sensing by Measuring Ionic Current Waveform through Micropores.

Kazumichi Yokota,Masato Tanaka,Kazuaki Kajimoto,Muneaki Hashimoto,Masateru Taniguchi,Masatoshi Kataoka,Makusu Tsutsui,Yoshihiro Nakajima,Sanae Murayama

doi:10.3390/bios11030078

Abstract

Immunostaining has been widely used in cancer prognosis for the quantitative detection of cancer cells present in the bloodstream. However, conventional detection methods based on the target membrane protein expression exhibit the risk of missing cancer cells owing to variable protein expressions. In this study, the resistive pulse method (RPM) was employed to discriminate between cultured cancer cells (NCI-H1650) and T lymphoblastoid leukemia cells (CCRF-CEM) by measuring the ionic current response of cells flowing through a micro-space. The height and shape of a pulse signal were used for the simultaneous measurement of size, deformability, and surface charge of individual cells. An accurate discrimination of cancer cells could not be obtained using 1.0 × phosphate-buffered saline (PBS) as an electrolyte solution to compare the size measurements by a microscopic observation. However, an accurate discrimination of cancer cells with a discrimination error rate of 4.5 ± 0.5% was achieved using 0.5 × PBS containing 2.77% glucose as the electrolyte solution. The potential application of RPM for the accurate discrimination of cancer cells from leukocytes was demonstrated through the measurement of the individual cell size, deformability, and surface charge in a solution with a low electrolyte concentration.

Highlights

The resistive pulse method (RPM), which is used to evaluate the transient ionic current blockade associated with the translocation of an individual nano- to micro-sized particle passing through a pore, can probe small objects as pulse-like electrical signals
We employed cancer cells (NCI-H1650) that are relatively smaller compared to other cancer cells and overlap with leukocytes (CCRF-CEM) [15,28,29]
The cancer cells in 1.0 × phosphate-buffered saline (PBS) were statistically discriminated from the leukocytes owing to their larger cell size

Summary

Introduction

The resistive pulse method (RPM), which is used to evaluate the transient ionic current blockade associated with the translocation of an individual nano- to micro-sized particle passing through a pore, can probe small objects as pulse-like electrical signals. These objects can be discriminated at a single-particle resolution because the measured ionic current blockade signals possess information regarding the physical properties of these particles, such as size [1], shape [2,3,4], surface charge [1,5], and deformability [6,7]. We demonstrate the accuracy of the RPM in distinguishing cancer cells from leukocytes

Methods

Results

Conclusion