Biology subjects

Solis Fernandez, G.

Publications and source records attributed to Solis Fernandez, G..

4 recordsLinked to original sources

bioRxiv2026

Synthetic Fibrous Hydrogels as Minimal Systems to Modulate Cell Migration Modes in 3D

Cell migration in three-dimensional (3D) environments is highly plastic and regulated by extracellular matrix (ECM) cues. Engineered biomaterials provide controllable platforms to investigate how specific matrix signals regulate cell behavior in 3D, yet how defined biochemical signals control migration modes remain unclear. Here, we present tunable fibrous polyisocyanide (PIC) hydrogels functionalized with integrin-binding RGD peptides, cadherin-mimetic HAVDI peptides, or no ligands to direct mesenchymal, hybrid, or amoeboid-like migration of human adipose-derived stem cells without altering matrix mechanics. Using live-cell tracking, 3D displacement microscopy, matrix remodeling analysis, and YAP nuclear localization, we show that ligand identity governs adhesion organization, force transmission, and mechanotransduction. RGD-functionalized matrices promote {beta}1-integrin clustering, extensive matrix remodeling, strong YAP activation and upregulation of migration-related genes. In contrast, non-adhesive matrices limit adhesion formation, resulting in weak force transmission and amoeboid-like behavior. HAVDI-functionalized matrices induce cadherin clustering and heterogeneous cellular responses, indicating that a hybrid migration mode arises from adhesion organization rather than a distinct transcriptional program. Together, these findings demonstrate that ligand identity alone is sufficient to program migration mode in a force-responsive 3D matrix and provide a versatile platform to dissect cell-matrix interactions in complex environments. Statement of significanceO_LICell migration in tissues is highly adaptable, yet precise control of migration modes in defined 3D biomaterials remains challenging. C_LIO_LIWe introduce fibrous PIC hydrogels presenting RGD, HAVDI, or no adhesive ligands to bias human stem cells toward mesenchymal-like, hybrid, or amoeboid-like migration states. C_LIO_LIBy linking ligand identity to adhesion organization, matrix remodeling, YAP mechanotransduction, and gene expression, this work provides a minimal platform to dissect and engineer 3D cell-matrix interactions C_LI

biophysics↗

bioRxiv2026

Label-Free Monitoring of Cancer-associated Fibroblast Activation using NADH Fluorescence Lifetime Imaging

Cancer-associated fibroblasts (CAFs) are key regulators of tumor progression, yet their activation state is commonly assessed using static, endpoint assays that do not allow dynamic analysis in living cells. Although CAF activation is accompanied by pronounced metabolic remodeling, label-free approaches that exploit these changes for real-time monitoring remain limited. Here, we demonstrate that NADH fluorescence lifetime imaging microscopy (FLIM) provides a non-invasive readout of this process. CAFs activated with transforming growth factor beta (TGF-{beta}) exhibit a reproducible shift toward longer NADH fluorescence lifetimes compared to non-activated cells, consistent with changes in the relative contributions of free and protein-bound NADH. By combining live-cell FLIM with -smooth muscle actin staining in the same cells, we directly link metabolic signatures to cellular activation state. We further demonstrate the potential of this approach to dynamically monitor CAF activation in live, migrating cells. Together, these results establish NADH fluorescence lifetime imaging as a label-free metabolic approach for monitoring CAF activation dynamics, complementing conventional marker-based methods and enabling continuous monitoring of tumor-stroma interactions.

biochemistry↗

bioRxiv2025

Quantitative Analysis of Cytoplasmic Viscosity in Colorectal Cancer Cells by Differential Dynamic Microscopy of Genetically Encoded Nanoparticles

The viscosity of the cytoplasm plays a key role in regulating molecular diffusion and cellular mechanics, yet quantifying it in living cells remains technically challenging. Genetically encoded multimeric nanoparticles (GEMs) have emerged as powerful probes for intracellular microrheology; however, current analyses rely on single-particle tracking, which is limited by probe density, imaging noise, and expression variability. Here, we combine GEMs with differential dynamic microscopy (DDM) to enable quantitative, non-invasive, and rapid measurement of intracellular viscosity using standard wide-field fluorescence imaging. DDM extracts particle dynamics from ensemble spatiotemporal intensity fluctuations, yielding reliable diffusion coefficients and viscosity values even in crowded or heterogeneous environments where tracking fails. Validation with fluorescent nanoparticles diffusing in water confirmed that DDM accurately reproduced theoretical viscosities across a wide range of particle sizes and concentrations. Comparison with single-particle tracking (SPT) demonstrated equivalent precision under dilute conditions and superior robustness under crowding. To showcase the potential of this approach, we applied GEM-DDM to colorectal cancer cell lines with different metastatic potentials. Cytoplasmic viscosity correlated with aggressiveness, increasing from 1.9-2.3 cP in poorly metastatic to 3.6-3.7 cP in highly metastatic lines, consistent with greater macromolecular crowding and cytoplasmic reorganization reported in aggressive cells. Together, these results establish GEM-DDM as a fast, reproducible, and accessible platform for intracellular microrheology, providing new opportunities to link the physical state of the cytoplasm to cell function and disease progression. Statement of significancePhysical properties such as cytoplasmic viscosity influence how molecules move and interact within cells, affecting metabolism, signalling, and disease progression. Measuring viscosity in living cells has been technically challenging and often invasive. Here, we introduce GEM-DDM as a quantitative, non-invasive image-based analysis method combining genetically encoded multimeric nanoparticles (GEMs) with differential dynamic microscopy (DDM) to measure intracellular viscosity using standard wide-field microscopy. We validate its accuracy against established single particle tracking (SPT) methods and demonstrate its biological relevance by showing that cytoplasmic viscosity increases with metastatic potential in cancer cells. This approach provides an accessible platform for studying how the physical state of cells influences their function and pathology.

biophysics↗

bioRxiv2025

Beyond One-Size-Fits-All: Tumor Biology Influences Nanoparticle Behaviour in Cancer Models

Nanoparticles (NPs) are a promising tool for cancer therapy, yet few have successfully reached clinical application. Current nanomedicine development pipelines are focused on optimizing physical properties of NPs, overlooking the impact of tumor biology on their behavior. Here, we show that the same NPs exhibit distinct accumulation and penetration patterns in 3D spheroids derived from four tumor models (representative of lung, colon, breast, and cervical cancer). We uncover an inverse relationship between NP uptake and penetration: tumors with slower internalization show deeper NP diffusion. Proteomic analysis revealed that tumor-specific expression of endocytic and extracellular matrix proteins underlies this variability. Our findings challenge the prevailing one-size-fits-all approach and highlight the need to integrate tumor biology into NP design. Tailoring NPs to the unique cellular and extracellular features of each tumor type will be critical for developing more effective and clinically relevant nanotherapies.

cell biology↗