We are pleased to share that an image from our recent article, “Protocol for quantifying coccidian parasite mechanics and rupture force using advanced micromanipulation-based piercing,” has been selected as the cover image for STAR Protocols, Volume 7, Issue 1 (20 March 2026).

The article presents a micromanipulation-based method to measure the mechanical properties and rupture forces of coccidian parasites.

🔗 Article

Image credit: Julien Husson. Cover image from STAR Protocols.

We are pleased to announce the publication of a new research article entitled “Stiffening cells with light”, resulting from a collaboration with Julien Husson at École Polytechnique.

Summary: Fluorescence microscopy is commonly used to observe living cells and organisms, but it can induce phototoxicity, which may lead to erroneous interpretations. The primary cause of phototoxic cell damage is the production of reactive oxygen species (ROS), which can crosslink intracellular proteins and nucleic acids. Using profile microindentation and atomic force microscopy, we demonstrate that excitation of various fluorescent probes causes a rapid dose-dependent increase in cell stiffness across multiple cell types. This photostiffening effect explains why T cells loaded with the Fluo-4 calcium probe stop protruding within seconds after light excitation. We show that upon fluorophore excitation, ROS production is correlated with increased stiffness, and we reproduce the effect by incubating cells with H₂O₂ or the photosensitizer pheophorbide a. This study underscores the importance of controls and proposes photostiffening as a method for quantifying phototoxicity.

🔗 Article
🔗 École Polytechnique news
🔗 Julien Husson’s website

Image credits: Julien Husson. Cover image from Cell Reports Physical Science.

Coccidian parasites can rely on their mechanical properties to infect their hosts. Here, we detail a microindentation-based technique for quantifying the wall mechanics of coccidian oocysts. We describe steps for micropipette fabrication, calibration of flexible microindenters, system assembly, and quantifying indentation and rupture forces. We then present procedures for automated data analysis using open-source software and programming languages. The protocol enables measurement of wall rupture forces and is applicable to study the integrity of parasites under various physiological conditions.

https://doi.org/10.1016/j.xpro.2025.104234