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Updated: May 13, 2026
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Mapping Absolute DNA Density in Cell Nuclei using Single-molecule Localization Microscopy
Published on: November 11, 2025
Intracellular protein and nucleic acid measured in eight cell types using deep-ultraviolet mass mapping
Man C Cheung1, Rebecca LaCroix, Brian K McKenna
1Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215, USA. mc.cheung@gmail.com
Summary
Deep-ultraviolet mass mapping precisely measured nucleic acid and protein in various cell types. The nucleic acid/protein ratio proved a stable cell characteristic useful for phenotyping and identifying embryo origins.
Area of Science:
- Cell biology
- Biophysics
- Biochemistry
Background:
- Accurate quantification of cellular components is crucial for understanding cell function and differentiation.
- Existing methods like flow cytometry and fluorescence microscopy require calibration for absolute mass measurements.
- Variability in cellular composition can impact cell-based assays and diagnostics.
Purpose of the Study:
- To present deep-ultraviolet mass mapping measurements of nucleic acid (NA) and protein in various cell types.
- To establish a calibration for absolute mass determination in both mass mapping and fluorescence-based techniques.
- To investigate the cell-type-specific and embryo-specific variations in cellular composition and the utility of the NA/protein ratio for phenotyping.
Main Methods:
- Deep-ultraviolet mass mapping was employed to measure the dry mass distribution of NA and protein at submicron resolution on a single-cell basis.
- Spectrophotometric standards (molar extinction coefficient) were used for absolute weight calibration.
- Measurements were performed on five cultured cell lines, three primary cell types, and individual blastomeres from mouse embryos.
Main Results:
- Cultured cell lines exhibited high NA concentrations in the nucleus, exceeding the genomic 2C number even in the G1 stage.
- The whole-cell NA/protein ratio was a consistent characteristic of cell lines, independent of the cell cycle.
- Primary chicken red blood cells showed lower nuclear NA content compared to cultured cell lines.
- Mouse embryo blastomeres displayed significant variation in total protein and NA content, but a more constant NA/protein ratio within embryos.
Conclusions:
- Deep-ultraviolet mass mapping provides accurate, calibrated measurements of cellular NA and protein.
- The NA/protein ratio serves as a valuable, stable phenotyping characteristic for cell lines and an identifier for embryo origins.
- Cellular composition, particularly the NA/protein ratio, varies significantly between cell types and even between individual cells within early embryos.
