Benchtop IR Imaging of Live Cells: Monitoring the Total Mass of Biomolecules in Single Cells

Published

September 4, 2024

Author(s)

Yow-Ren Chang, Seongmin Kim, Young Jong Lee

Abstract

Absolute quantity imaging of biomolecules on a single cell level is critical for measurement assurance in biosciences and bioindustries. While infrared (IR) transmission microscopy is a powerful label-free imaging modality capable of chemical quantification, its applicability to hydrated biological samples remains challenging due to the strong IR absorption by water. Traditional IR imaging of hydrated cells relies on powerful light sources, such as synchrotrons, to mitigate the light absorption by water. However, we overcome this challenge by applying a solvent absorption compensation (SAC) technique to a home-built benchtop IR microscope based on an external-cavity quantum cascade laser. SAC-IR microscopy adjusts the incident light using a pair of polarizers to pre-compensate the IR absorption by water while retaining the full dynamic range. Integrating the IR absorbance over a cell yields the total mass of biomolecules per cell. We monitor the total mass of the biomolecules of live fibroblast cells over twelve hours, demonstrating promise for advancing our understanding of the biomolecular processes occurring in live cells on the single-cell level.

Citation

Analytical Chemistry

Volume

96

Issue

37

Pub Type

Journals

Download Paper

https://doi.org/10.1021/acs.analchem.4c02108

Local Download

Keywords

IR absorption, label-free chemical imaging, live cell imaging

Citation

Chang, Y. , Kim, S. and Lee, Y. (2024), Benchtop IR Imaging of Live Cells: Monitoring the Total Mass of Biomolecules in Single Cells, Analytical Chemistry, [online], https://doi.org/10.1021/acs.analchem.4c02108, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935425 (Accessed October 9, 2025)