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bioRxiv · 10.1101/2025.11.20.685382

Targeted fluorescent lipid microparticles for quantitative measurement of phagosomal pH

Michelis, S.·Uhl, H.·Niedergang, F.·Fattaccioli, J.·Dumat, B.·Mallet, J.-M.
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Abstract

Phagosomal acidification plays a pivotal role in pathogen destruction and immune signaling, yet tools capable of reporting these biochemical changes with spatial and mechanistic precision remain scarce. A modular biosensing strategy is presented in which BODIPY-derived hydrophilic fluorophores are conjugated to phospholipids and incorporated at the surface of targeted lipid microparticles. These soft and biomimetic particles combine receptor-specific uptake with ratiometric fluorescence readouts, enabled by pairing pH-responsive dyes at the interface with a pH-invariant reference probe in the core. Following Fc{gamma} receptor-mediated internalization by macrophages, the particles deliver real-time insight into the onset and progression of phagosomal acidification. This versatile platform provides a direct means to couple defined surface recognition events to intracellular pH measurements, offering new opportunities to unravel how particle identity and ligand presentation modulate phagosomal physiology.

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Michelis, S., Uhl, H., Niedergang, F., Fattaccioli, J., Dumat, B., Mallet, J.-M.. 2025-11-20. Targeted fluorescent lipid microparticles for quantitative measurement of phagosomal pH. https://doi.org/10.1101/2025.11.20.685382

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