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bioRxiv · 10.64898/2026.03.27.714905

Light-dependent cell fixing with DNA-targeting fluorophores

Carraz, M.·Bosch, S.·Mangeat, T.·Cantaloube, S.·Amarh, V.·Duval, R.
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Abstract

Light has become of paramount importance for the spatiotemporal control of cell labeling, activity and death. We found that palmatine, a DNA-binding alkaloid, mediates the fixation of live cells upon visible light irradiation. Fixation takes a few seconds or minutes depending on the power used, is accompanied by nuclear fluorescent labeling in target cells, exhibits a high degree of control from cell islets to single cells, yielding cells with intact nucleus and membrane boundaries. 'Optofixation' relies on palmatine-DNA interaction, singlet oxygen photogeneration and lipid peroxidation, producing fixing levels of endogenous aldehydes. We also establish that many commonly used nuclear dyes exhibit optofixation properties across the UV-far red spectrum. Comprising the straightforward inactivation and labeling of native target cells by small fluorophores, this unprecedented, comparatively simple technology has the potential for major applications in biological research.

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Carraz, M., Bosch, S., Mangeat, T., Cantaloube, S., Amarh, V., Duval, R.. 2026-03-28. Light-dependent cell fixing with DNA-targeting fluorophores. https://doi.org/10.64898/2026.03.27.714905

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