Exploring rare cellular activity in more than one million cells by a transscale scope

T Ichimura,T Nagai,K Horikawa,H Hashimoto,K Fujita,T M Watanabe,T Kakizuka,A Kasai,K Seiriki

doi:10.1038/s41598-021-95930-7

Abstract

In many phenomena of biological systems, not a majority, but a minority of cells act on the entire multicellular system causing drastic changes in the system properties. To understand the mechanisms underlying such phenomena, it is essential to observe the spatiotemporal dynamics of a huge population of cells at sub-cellular resolution, which is difficult with conventional tools such as microscopy and flow cytometry. Here, we describe an imaging system named AMATERAS that enables optical imaging with an over-one-centimeter field-of-view and a-few-micrometer spatial resolution. This trans-scale-scope has a simple configuration, composed of a low-power lens for machine vision and a hundred-megapixel image sensor. We demonstrated its high cell-throughput, capable of simultaneously observing more than one million cells. We applied it to dynamic imaging of calcium ions in HeLa cells and cyclic-adenosine-monophosphate in Dictyostelium discoideum, and successfully detected less than 0.01% of rare cells and observed multicellular events induced by these cells.

Highlights

In many phenomena of biological systems, not a majority, but a minority of cells act on the entire multicellular system causing drastic changes in the system properties
The pixel size of image sensors widely used in recent biology, scientific complementary metal oxide semiconductor and electron-magnifying charge-coupled devices (EMCCD) cameras, is typically 6.5 μm or 16 μm, respectively, which requires at least 5 × magnification for spatial sampling of single cells
We selected a wide-field imaging configuration for AMATERAS1.0 (Fig. 1a), rather than laser scan imaging, and used a single CMOS chip as it facilitates the recording of the entire FOV

Summary

Introduction

In many phenomena of biological systems, not a majority, but a minority of cells act on the entire multicellular system causing drastic changes in the system properties. Such issues are common in various research areas of medicine and biology, including developmental biology1, neuroscience2,3, oncology[4], and immunology[5] To tackle this challenge, it is essential to develop an optical microscope system for single-cell imaging within macroscale dynamics in a wide field-of-view (FOV), which enables dynamic observation of a huge number of cells at the same time. The amount of photon per pixel is proportional to the square of the ratio of pixel size to magnification, so a decrease in pixel size cancels out with a decrease in magnification This simple configuration enables fluorescence imaging with sub-cellular resolution and practically sufficient signal-to-noise ratio in a vast FOV of 14.6 × 10.1 mm[2], which can achieve cell throughput of more than one million cells in a single shot

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