Non-invasive microscopy detects activation state and distinguishes between cell types

November 20, 2019

Most analytical methods in biology require invasive procedures to analyze samples, which leads to irreversible changes or even their destruction. Furthermore, the sensitivity of such approaches often stems from the averaging of signals generated by a large number of cells, making it impossible to study the underlying heterogeneity of responses.

In the medical field, X-ray and MRI imaging are highly useful since they allow diagnosis through non-invasive imaging. Similarly, label-free techniques are becoming increasingly popular in microscopy thanks to their non-invasiveness. Quantitative phase1 microscopy, along with Raman spectroscopy2, are label-free techniques used in this study to extract biomarkers based on cellular morphology and intracellular content. These approaches have been previously used to characterize specimens and identify cells from different origins; however, the measurement of finer features than the cell type with these techniques has proven to be challenging.

Assistant Professor Nicolas Pavillon and Associate Professor Nicholas I. Smith of the Immunology Frontier Research Center (IFReC) at Osaka University developed a label-free multimodal imaging platform that enables the study of cell cultures non-invasively without the need of any contrast agent. The pair of researchers showed how the label-free signals can be employed to create models that can detect the activation state of macrophage cells and distinguish between different cell types even in the case of highly heterogeneous populations of primary cells. "We devised specific statistical tools that allow for the identification of the best methods for detecting responses at the single-cell level, and show how these models can also identify different specimens, even within identical experimental conditions, allowing for the detection of outlier behaviors," says Associate Professor Smith.

The findings of this study show that a non-invasive optical approach, which enables the study of live samples without requiring contrast agents, can also achieve high sensitivity at the single-cell level. "In particular," says Assistant Professor Pavillon, "our results show that this method can identify different cell sub-types and their molecular changes during the immune response, as well as outlier behaviors between specimens."
The article, "Immune cell type, cell activation, and single cell heterogeneity revealed by label-free optical methods" was published in Scientific Reports at DOI:


1. Quantitative phase microscopy

An optical imaging method that enables dynamic measurement of live cell cultures, providing quantitative information about the local optical density of cells, related to the refractive index.

2. Raman spectroscopy

An optical method that measures the vibrational modes of molecules, enabling their identification through spectral features. Applied to living cells, it is an indirect non-invasive method to assess their molecular content.

About Osaka University

Osaka University was founded in 1931 as one of the seven imperial universities of Japan and now has expanded to one of Japan's leading comprehensive universities. The University has now embarked on open research revolution from a position as Japan's most innovative university and among the most innovative institutions in the world according to Reuters 2015 Top 100 Innovative Universities and the Nature Index Innovation 2017. The university's ability to innovate from the stage of fundamental research through the creation of useful technology with economic impact stems from its broad disciplinary spectrum.


Osaka University

Related Microscopy Articles from Brightsurf:

Ultracompact metalens microscopy breaks FOV constraints
As reported in Advanced Photonics, their metalens-integrated imaging device (MIID) exhibits an ultracompact architecture with a working imaging distance in the hundreds of micrometers.

Attosecond boost for electron microscopy
A team of physicists from the University of Konstanz and Ludwig-Maximilians-Universität München in Germany have achieved attosecond time resolution in a transmission electron microscope by combining it with a continuous-wave laser -- new insights into light-matter interactions.

Microscopy beyond the resolution limit
The Polish-Israeli team from the Faculty of Physics of the University of Warsaw and the Weizmann Institute of Science has made another significant achievement in fluorescent microscopy.

Quantum light squeezes the noise out of microscopy signals
Researchers at the Department of Energy's Oak Ridge National Laboratory used quantum optics to advance state-of-the-art microscopy and illuminate a path to detecting material properties with greater sensitivity than is possible with traditional tools.

Limitations of super-resolution microscopy overcome
The smallest cell structures can now be imaged even better: The combination of two microscopy methods makes fluorescence imaging with molecular resolution possible for the first time.

High-end microscopy refined
New details are known about an important cell structure: For the first time, two Würzburg research groups have been able to map the synaptonemal complex three-dimensionally with a resolution of 20 to 30 nanometres.

Developing new techniques to improve atomic force microscopy
Researchers from the University of Illinois at Urbana-Champaign have developed a new method to improve the noise associated with nanoscale chemical imaging using atomic force microscopy.

New discovery advances optical microscopy
New Illinois ECE research is advancing the field of optical microscopy, giving the field a critical new tool to solve challenging problems across many fields of science and engineering including semiconductor wafer inspection, nanoparticle sensing, material characterization, biosensing, virus counting, and microfluidic monitoring.

New microscopy method provides unprecedented look at amyloid protein structure
Neurodegenerative diseases such as Alzheimer's and Parkinson's are often accompanied by amyloid proteins in the brain that have become clumped or misfolded.

Novel 3D imaging technology makes fluorescence microscopy more efficient
A research team led by Dr Kevin Tsia from the University of Hong Kong (HKU), developed a new optical imaging technology -- Coded Light-sheet Array Microscopy (CLAM) -- which can perform 3D imaging at high speed, and is power efficient and gentle to preserve the living specimens during scanning at a level that is not achieved by existing technologies.

Read More: Microscopy News and Microscopy Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to