This experimental study asks how chemical preservation changes label-free stimulated Raman scattering images. The authors measured 2,325 cultured HeLa cells across live and five fixation conditions, comparing spectral shape, band intensity, cell area and lipid spatial distribution. Formaldehyde-based fixatives best retained lipid spatial patterns; glutaraldehyde increased signal with little change in area, whereas alcohol fixation reduced lipid signal and reorganized cellular structures. The study compared separate cell populations in a single imaging plane; it did not measure paired changes i

A sample can hold its shape and still lose part of its chemical story. What does a preservative change in the image?

A study in Analytical Chemistry · 2026 Ceconello, Han, Manifold, Polli & Streets

Same question. Different chemical image.

Start with a living cell. Choose a preservative and watch the image change. Then switch to the microscope images that inspired this model.

Live cells

The starting point: lipid-rich regions and protein-rich structures in living HeLa cells.

604 cells measured

The cell’s projected size follows measured mean cross-sectional area. Structures, dots and scanning motion are illustrative. The model is not a measured before-and-after cell.

The study compared separate populations of cultured HeLa cells. The numbers are population means. Signal intensity is a measurement in arbitrary units, not a direct count of lipid or protein molecules. At 2850 cm⁻¹, the contrast is mainly lipid-sensitive; 2920 cm⁻¹ contains both protein and lipid contributions. In Figure 4, blue protein-rich contrast was obtained by subtracting a rescaled lipid-sensitive image from the mixed image.

Preserving a cell is a chemical intervention. What you keep depends on what you want to measure.

Seeing chemistry, without a label.

Stimulated Raman scattering, or SRS, uses molecular vibrations to make an image. Here, different vibrations reveal different aspects of cell chemistry.

Two beams. One vibration.

When the difference between two laser frequencies matches a molecular vibration, energy passes between the beams. This provides contrast from carbon–hydrogen bonds.

Different windows into a cell.

The 2850 cm⁻¹ band mainly reveals lipids. The 2920 cm⁻¹ band includes proteins and lipids. Combining the images helps distinguish lipid-rich and protein-rich regions.

Hold together. Or wash away.

Aldehyde fixatives form links between proteins. Alcohols precipitate biomolecules and can extract lipids. Both can change the structure and the signal you see.

A change you can measure.

2,325 cells. Six conditions. Compare the average result and the middle half of each population.

Methanol-treated cells had a 42% lower mean lipid-sensitive signal than live cells. This is a change in measured intensity, not a direct count of lost lipids.

Percent changes calculated from reported means. Middle 50%: 25th–75th percentile. Data: supplementary Tables S1–S4.

Each row is a separate population. Choose a row to inspect that condition at the bench.

What do you want to keep?

A useful preservative depends on the scientific question. Choose a priority to see how the paper’s findings inform that choice.

Select something you want to preserve. There is more than one way for a sample to stay “the same.”

Follow the evidence.

Effects of Chemical Fixation on Stimulated Raman Scattering Microscopy

Chiara Ceconello · Wuji Han · Bryce Manifold · Dario Polli · Aaron Streets

Analytical Chemistry, 2026.

From experiment to exploration

The researchers measured cultured HeLa cells, a human cervical cancer cell line, using SRS microscopy across 16 spectral points from 2820 to 3012 cm⁻¹. The interactive cell translates the reported comparisons into a conceptual visual model. It does not represent measured three-dimensional volume or dynamics.

Microscopy images: Figure 4, Ceconello et al., Analytical Chemistry (2026), CC BY 4.0. Panels cropped from the figure; colors unchanged. Graphical abstract: AI-generated conceptual illustration inspired by Figure 4, not a microscopy image. Plotted summaries are transcribed from supplementary Tables S1–S4; plots and percent calculations created for this experience. Supplementary materials are provided by the authors under CC BY-NC 4.0.