Català Castro, FredericOrtiz Vásquez, SantiagoMartínez Fernández, CarmenPezzano, FabioGarcia-Cabau, CarlaFernández-Campo, MartínSanfeliu-Cerdán, NeusJiménez-Delgado, SendaSalvatella, XavierRuprecht, VerenaFrigeri, Paolo-AntonioKrieg, Michael2025-02-252025-02-252025Català-Castro F, Ortiz-Vásquez S, Martínez-Fernández C, Pezzano F, Garcia-Cabau C, Fernández-Campo M, et al. Measuring age-dependent viscoelasticity of organelles, cells and organisms with time-shared optical tweezer microrheology. Nat Nanotechnol. 2025 Jan 2. DOI: 10.1038/s41565-024-01830-y1748-3387http://hdl.handle.net/10230/69730Data de publicació electònica: 02-01-2025Quantifying the mechanical response of the biological milieu (such as the cell's interior) and complex fluids (such as biomolecular condensates) would enable a better understanding of cellular differentiation and aging and accelerate drug discovery. Here we present time-shared optical tweezer microrheology to determine the frequency- and age-dependent viscoelastic properties of biological materials. Our approach involves splitting a single laser beam into two near-instantaneous time-shared optical traps to carry out simultaneous force and displacement measurements and quantify the mechanical properties ranging from millipascals to kilopascals across five decades of frequency. To create a practical and robust nanorheometer, we leverage both numerical and analytical models to analyse typical deviations from the ideal behaviour and offer solutions to account for these discrepancies. We demonstrate the versatility of the technique by measuring the liquid-solid phase transitions of MEC-2 stomatin and CPEB4 biomolecular condensates, and quantify the complex viscoelastic properties of intracellular compartments of zebrafish progenitor cells. In Caenorhabditis elegans, we uncover how mutations in the nuclear envelope proteins LMN-1 lamin A, EMR-1 emerin and LEM-2 LEMD2, which cause premature aging disorders in humans, soften the cytosol of intestinal cells during organismal age. We demonstrate that time-shared optical tweezer microrheology offers the rapid phenotyping of material properties inside cells and protein blends, which can be used for biomedical and drug-screening applications.application/pdfeng© The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.info:eu-repo/semantics/articlehttp://dx.doi.org/10.1038/s41565-024-01830-yBiological physicsBiomaterialsBiomedical engineeringBiosensorsCharacterization and analytical techniquesinfo:eu-repo/semantics/openAccess