bims-ecemfi Biomed News
on ECM and fibroblasts
Issue of 2025–10–19
sixteen papers selected by
Badri Narayanan Narasimhan, University of California, San Diego
  1. Sp1 mechanotransduction regulates breast cancer cell invasion in engineered viscoelastic extracellular matrices.
  2. Piezo1 regulates the mechanotransduction of soft matrix viscoelasticity.
  3. Quantifying cell traction forces at the single-fiber scale in 3D: An approach based on deformable photopolymerized fiber arrays.
  4. BEHAV3D Tumor Profiler to map heterogeneous cancer cell behavior in the tumor microenvironment.
  5. Integrin-Piezo1 Axis Drives ECM Remodeling and Invasion of 3D Breast Epithelium.
  6. Invasin-functionalized PIC hydrogels enable long-term 3D culture of epithelial organoids.
  7. Ion-Mediated Progressively Stiffening Hydrogels for Vascularized Bone Regeneration.
  8. Dimensional memory in glioblastoma mechanics: Traction force analysis of cells cultured in 2D versus 3D collagen environments.
  9. In vivo mechano-tissue engineering by hydrogels capable of transmitting intercellular mechanical stress.
  10. Redefine tumor spheroids heterogeneity via PCA-coupled biophysical characterization.
  11. STRUCTURAL INSTABILITY OF THE SUPERFICIAL LAYERS OF THE FIBRINOGEN MATRIX CONTRIBUTES TO ITS NONADHESIVE PROPERTIES.
  12. Applications of synthetic polymers directed toward living cells.
  13. Bubble-driven cell detachment.
  14. Laminin-511-functionalized fibrin gel enables in-gel proliferation of human induced pluripotent stem cells.
  15. Exploring bacteria-surface interactions with a fluorescent membrane tension probe.
  16. Bioactive and degradable peg hydrogels: A multifunctional approach for tissue regeneration and antibacterial protection.
  1. Biomaterials. 2025 Oct 03. pii: S0142-9612(25)00674-X. [Epub ahead of print]327 123755
    Sp1 mechanotransduction regulates breast cancer cell invasion in engineered viscoelastic extracellular matrices.
    Abhishek Sharma, Rowan F Steger, Jen M Li, Samuel Y Fong, Neha Saxena, Jane A Baude, Kellie A Heom, Siddharth S Dey, Ryan S Stowers.
      Breast cancer progression involves extensive remodeling of the extracellular matrix (ECM), including increased stiffness, altered viscoelasticity (stress relaxation), and elevated collagen levels. While in vitro experiments have revealed a role for each of these factors in individually promoting malignant behavior, their combined effects remain unclear. Here, we engineered alginate-collagen hydrogels with independently tunable stiffness, stress relaxation, and collagen density to dissect how the complex ECM environment regulates cancer cell phenotype. We show that high stiffness, fast stress relaxation, and high collagen density led to changes in cell morphology, marked by decreased roundness, and promoted spheroid invasion in both breast cancer and non-transformed mammary epithelial cells. Single cell migration speed and displacement were greatest in matrices of high stiffness, low collagen density, and slow stress relaxation. RNA-seq and Cleavage Under Targets and Tagmentation (CUT&Tag)-seq revealed that high stiffness and fast stress relaxing groups were enriched for Sp1 target gene expression as well as increased Sp1 binding at genomic loci. Notably, analysis of publicly available claudin-low breast cancer data showed that high expression of the Sp1-regulated genes in fast stress relaxing groups was correlated with significantly reduced patient survival. Mechanistically, we found that phosphorylated Sp1 (T453) exhibited increased nuclear localization in matrices with high stiffness and fast stress relaxation. Furthermore, Sp1 phosphorylation was regulated by PI3K and ERK1/2 activity, as well as actomyosin contractility. Our tunable hydrogel platform reveals that multiple tumor-mimicking cues within complex viscoelastic microenvironments reinforce malignant traits, with Sp1 acting as a mechanoresponsive transcription factor that transduces these signals.
    DOI:  https://doi.org/10.1016/j.biomaterials.2025.123755
  2. Nat Commun. 2025 Oct 15. 16(1): 9155
    Piezo1 regulates the mechanotransduction of soft matrix viscoelasticity.
    Mariana A G Oliva, Giuseppe Ciccone, Gotthold Fläschner, Jiajun Luo, Jonah L Voigt, Patrizia Romani, Paul Genever, Oana Dobre, Sirio Dupont, Massimo Vassalli, Pere Roca-Cusachs, Manuel Salmeron-Sanchez.
      Mechanosensitive ion channels such as Piezo1 have fundamental roles in sensing the mechanical properties of the extracellular matrix. However, whether and how Piezo1 senses time-dependent matrix mechanical properties, that is, viscoelasticity, remains unknown. To address this question, we combine an immortalised mesenchymal stem cell line, in which Piezo1 expression can be silenced, with soft and stiff viscoelastic hydrogels that have independently tuneable elastic and viscous moduli. We demonstrate that Piezo1 is a regulator of the mechanotransduction of viscoelasticity in soft matrices, both experimentally and through simulations incorporating Piezo1 into a modified viscoelastic molecular clutch model. Using RNA sequencing, we also identify the transcriptomic responses of mesenchymal stem cells to matrix viscoelasticity and Piezo1 activity, identifying gene signatures that reflect their mechanobiology in soft and stiff viscoelastic hydrogels.
    DOI:  https://doi.org/10.1038/s41467-025-64185-5
  3. Proc Natl Acad Sci U S A. 2025 Oct 21. 122(42): e2507677122
    Quantifying cell traction forces at the single-fiber scale in 3D: An approach based on deformable photopolymerized fiber arrays.
    Pierre Ucla, Joanne Lê-Chesnais, Henri Ver Hulst, Xingming Ju, Isabel Calvente, Elnaz Nematollahi, Ludovic Leconte, Jean Salamero, Isabelle Bonnet, Catherine Monnot, Hélène D Moreau, Jessem Landoulsi, Vincent Semetey, Sylvie Coscoy.
      The forces exerted by cells upon the fibers of the extracellular matrix play a decisive role in cell motility in physiopathology. How the local physical properties of the matrix (density, stiffness, orientation) affect cellular forces remains, however, poorly understood. Existing approaches to measure cell three-dimensional (3D) traction forces within fibrous substrates lack control over the local properties and rely on continuum approaches, not suited for measuring forces at the scale of individual fibers. Herein, an approach is proposed to fabricate multilayer arrays of suspended deformable fibers spanning a wide range of fine-tunable geometrical and mechanical properties using two-photon polymerization. Atomic Force Microscopy is used to thoroughly investigate the properties of individual fibers, including Young's modulus and stiffness. This approach is combined with a reference-free method for measuring traction forces in 3D, which relies on automated segmentation of the fibers coupled with finite element modeling. The force measurement pipeline is applied to study forces exerted by endothelial cells, fibroblasts, or macrophages, and reveals how these forces are influenced by fiber density and stiffness. Additionally, coupling to fast volumetric imaging with lattice light-sheet microscopy enables the measurement of the low-intensity and short-lived tractions exerted by amoeboid cells, such as dendritic cells. Our technology will be instrumental for monitoring and studying cell behavior at the single-fiber level at extracellular matrix density interfaces, which play a crucial role in both physiological and pathological contexts, such as tumor boundaries.
    Keywords:  3D traction forces; atomic force microscopy; cell contractility; fibers; two-photon polymerization
    DOI:  https://doi.org/10.1073/pnas.2507677122
  4. Elife. 2025 Oct 15. pii: RP102097. [Epub ahead of print]13
    BEHAV3D Tumor Profiler to map heterogeneous cancer cell behavior in the tumor microenvironment.
    Emilio Rios-Jimenez, Anoek Zomer, Raphael Collot, Mario Barrera Román, Sandra F Archidona, Hendrikus Ariese, Ravian van Ineveld, Michiel Kleinnijenhuis, Nils Bessler, Hannah Johnson, Caleb A Dawson, Anne Rios, Maria Alieva.
      Intravital microscopy (IVM) enables live imaging of animals at single-cell level, offering essential insights into cancer progression. This technique allows for the observation of single-cell behaviors within their natural 3D tissue environments, shedding light on how genetic and microenvironmental changes influence the complex dynamics of tumors. IVM generates highly complex datasets that often exceed the analytical capacity of traditional uni-parametric approaches, which can neglect single-cell heterogeneous in vivo behavior and limit insights into microenvironmental influences on cellular behavior. To overcome these limitations, we present BEHAV3D Tumor Profiler (BEHAV3D-TP), a computational framework that enables unbiased single-cell classification based on a range of morphological, environmental, and dynamic single-cell features. BEHAV3D-TP integrates with widely used 2D and 3D image processing pipelines, enabling researchers without advanced computational expertise to profile cancer and healthy cell dynamics in IVM data from mouse models. Here, we apply BEHAV3D-TP to study diffuse midline glioma (DMG), a highly aggressive pediatric brain tumor characterized by invasive progression. By extending BEHAV3D-TP to incorporate tumor microenvironment (TME) data from IVM or fixed correlative imaging, we demonstrate that distinct migratory behaviors of DMG cells are associated with specific TME components, including tumor-associated macrophages and vasculature. BEHAV3D-TP enhances the accessibility of computational tools for analyzing the complex behaviors of cancer cells and their interactions with the TME in IVM data.
    Keywords:  cancer biology; cell migration; computational biology; confocal microscopy; image analysis; mouse; systems biology
    DOI:  https://doi.org/10.7554/eLife.102097
  5. Adv Sci (Weinh). 2025 Oct 13. e09932
    Integrin-Piezo1 Axis Drives ECM Remodeling and Invasion of 3D Breast Epithelium.
    Kabilan Sakthivel, Anna Kotowska, Zhimeng Fan, Ellen Juel Portner, Catherine Merry, Pontus Nordenfelt, Adam Cohen Simonsen, Amanda J Wright, Vinay S Swaminathan.
      Stiffening of tissue is a hallmark of cancer progression, promoting invasive phenotypes through altered cell-extracellular matrix (ECM) interactions. However, how fully formed epithelial structures respond to mechanical cues within their native ECM environment remains poorly understood. Here, using a 3D in situ stiffening hydrogel system that enables modulation of stiffness around mature normal mammary acini, it uncovers critical steps in ECM remodeling and invasion of epithelial structures and discover molecular mechanisms driving this process. Stiffening around mature acini triggers two temporally distinct phases of epithelial remodeling, a rapid priming phase involving basement membrane (laminin, LN) disruption and fibronectin (FN) secretion, followed by a delayed invasion phase characterized by FN remodeling and LN re-deposition that coincides with acinar proliferation and invasion. Mechanistically, it is shown that these changes are mediated by α3β1- and α5β1-integrin-focal adhesion kinase (FAK) signaling, which in turn activates the mechanosensitive ion channel Piezo1 to regulate ECM composition, remodeling, and acinar invasion. Together, the findings reveal how mature epithelial structures dynamically respond to mechanical stiffening to create an invasive niche, offering new insights into how tissue architecture and stiffness synergize to drive breast cancer progression.
    Keywords:  3D Mechanotransduction; ECM remodeling; Integrin signaling; Mammary acini; Stretch activated channels
    DOI:  https://doi.org/10.1002/advs.202509932
  6. Proc Natl Acad Sci U S A. 2025 Oct 21. 122(42): e2507500122
    Invasin-functionalized PIC hydrogels enable long-term 3D culture of epithelial organoids.
    Joost J A P M Wijnakker, Sangho Lim, Robin Schreurs, João Ferreira Faria, Jeroen Korving, Harry Begthel, Kirti K Iyer, Paul H J Kouwer, Hans Clevers.
      Tissue stem cell (TSC)-derived epithelial organoids are typically cultured in Matrigel [T. Sato et al., Nature 459, 262-265 (2009)], an extracellular matrix-like hydrogel produced from Engelbreth-Holm-Swarm sarcoma cells. This tumor is grown in the mouse abdomen [R. W. Orkin et al., J. Exp. Med. 145, 204-220 (1977)]. Previously, we demonstrated that the Yersinia membrane protein Invasin, coated on transwells, replaces Matrigel by activating β1-integrins, allowing long-term expansion of primary epithelial cells as 2D organoid sheets [J. J. A. P. M. Wijnakker et al., Proc. Natl. Acad. Sci. U.S.A. 122, e2420595121 (2025)]. Here, we functionalize a synthetic polyisocyanide (PIC) hydrogel with the integrin-activating domain of Invasin (INV). PIC hydrogels are soluble at 4 °C and form a gel at 37 °C [P. H. J. Kouwer et al., Nature 493, 651-655 (2013)]. When INV is covalently linked to PIC, the resulting hydrogel supports multipassage 3D growth of human intestinal and airway organoids. Self-renewal, polarization, and differentiation are maintained. The 3D swelling assay for cystic fibrosis drug testing (S. F. Boj et al., J. Vis. Exp. (2017), 10.3791/55159] was validated using PIC-INV. With PIC-INV hydrogels, we establish a fully defined and animal-free system for 3D TSC-derived organoid culture.
    Keywords:  Invasin; PIC; biomaterials; organoid; stem cells
    DOI:  https://doi.org/10.1073/pnas.2507500122
  7. Acta Biomater. 2025 Oct 15. pii: S1742-7061(25)00773-1. [Epub ahead of print]
    Ion-Mediated Progressively Stiffening Hydrogels for Vascularized Bone Regeneration.
    Wenhuan Bu, Jonathan I Dawson, Richard O C Oreffo, Matteo D'Este, David Eglin, Hongchen Sun, Alvaro Mata.
      The extracellular matrix (ECM) of tissues progressively changes its mechanical properties in processes such as tissue development, repair, and disease progression. While stiffness has become a key design parameter of biomaterials, most synthetic biomaterials employed in cell culture or tissue regeneration do not display these gradual changes in mechanical properties. Here, we report on a hydrogel platform with the capacity to exhibit progressive stiffening from 0.8 to 7.4 kPa within a ∼48 h time period. The material integrates the tyramine derivative of hyaluronic acid (HAT) and Laponite® (Lap) and harnesses the diffusion of cations from culture media to trigger gradual secondary Lap-HAT cross-linking, resulting in the progressive stiffening of the hydrogel. We assessed the applicability of the hydrogel by first using it as a substrate for in vitro culture to investigate cross-talk between human bone marrow stromal cells (HBMSCs) and human umbilical vein endothelial cells (HUVECs). The progressively stiffening hydrogel led to changes in cell morphology and enhanced differentiation and communication compared to control substrates. In addition, we also tested the potential of the progressively stiffening hydrogels for bone regeneration using a critical-size rat cranial defect model and found that the hydrogel construct promoted vascularized bone regeneration. The current study introduces a hydrogel material that offers a more physiologically relevant environment for in vitro and in vivo applications and provides insight into the mechanical complexity of the ECM and its role in tissue physiology. STATEMENT OF SIGNIFICANCE: This study presents a dynamic hydrogel platform that imitates the progressive mechanical changes of the native extracellular matrix (ECM), transitioning from soft (0.8 kPa) to stiff (7.4 kPa) over 48 hours. By co-assembling HAT and Lap, the hydrogel achieves gradual stiffening through cation diffusion - mediated gradual secondary Lap-HAT cross-linking, offering a physiologically relevant microenvironment. In vitro, it enhances HBMSC and HUVEC cross-talk, improving differentiation and morphology. In vivo, it promotes vascularized bone regeneration in a critical-size cranial defect model. This innovation bridges the gap between static synthetic biomaterials and dynamic ECM mechanics, advancing applications in tissue engineering, disease modeling, and regenerative medicine.
    Keywords:  angiogenesis; bone regeneration; hydrogels; progressively stiffening
    DOI:  https://doi.org/10.1016/j.actbio.2025.10.027
  8. Bioact Mater. 2026 Jan;55 515-528
    Dimensional memory in glioblastoma mechanics: Traction force analysis of cells cultured in 2D versus 3D collagen environments.
    Mishal Khan, Philipp Kollenz, Maret Fritzenschaft, Fereydoon Taheri, Federico Colombo, Johannes W Blumberg, Luise Schlotterose, Ulrich Sebastian Schwarz, Aldo Leal-Egaña, Christine Selhuber-Unkel.
      Glioblastoma (GB) is one of the most aggressive and lethal brain tumors, characterized by rapid proliferation, diffuse infiltrative growth, therapeutic resistance, and molecular heterogeneity. A major challenge in studying GB is the lack of in vitro models that accurately replicate the tumor's cellular characteristics observed in vivo, particularly the importance of three-dimensional (3D) models. This study investigated the traction stress exerted by LN229 and T98G human GB cell lines, as well as the HMC3 human microglia cell line, using traction force microscopy. First, cells were cultured on two-dimensional (2D) collagen-coated surfaces and within three-dimensional (3D) collagen-based bioactive matrices. Afterward, these cells were extracted and reseeded on flat polyacrylamide gels coated with collagen type I to perform traction force microscopy, thereby directly probing the mechanical memory imparted by their prior 2D or 3D environments. Our findings reveal that GB cells exert substantially higher traction stresses when cultured on 2D collagen-coated surfaces compared to those cultured in 3D bioactive matrices. This underscores the relevance of protein-based bioactive materials, such as collagen scaffolds, in replicating in vivo tumor microenvironments to study GB behavior. Single-cell nanoindentation and focal adhesions quantification were performed to offer mechanistic insights into glioblastoma and microglia cells. Interestingly, in addition to notable differences in traction stresses between cells cultured in 2D and 3D collagen environments, glioblastoma showed significant variation based on the cell type in terms of single-cell stiffness and focal adhesion metrics. These findings underscore the importance of complementary biophysical assays and realistic 3D bioactive matrices when studying GB mechanics in vitro.
    Keywords:  2D v/s 3D culture; 3D collagen substrate; Dimensional memory; Glioblastoma mechanics; Traction force microscopy
    DOI:  https://doi.org/10.1016/j.bioactmat.2025.09.025
  9. Nat Commun. 2025 Oct 15. 16(1): 8847
    In vivo mechano-tissue engineering by hydrogels capable of transmitting intercellular mechanical stress.
    Natsumi Ueda, Hayato Okazaki, Akihiro Mikuma, Ayane Kunieda, Soma Kawashima, Takeru Torii, Keiko Kawauchi, Masatake Matsuoka, Tomohiro Onodera, Norimasa Iwasaki, Koji Nagahama.
      Integrating the latest insights from mechanobiology into tissue engineering could lead to innovative technologies. Here we show a method to effectively elicit the regenerative response of transplanted cells by utilizing mechanical stress generated in vivo. The essential feature of our method is that it does not use specific ligands for the vital mechanosensor integrins to mechanically activate them. In our method, azide groups are introduced into the integrin, and the hydrogel is modified with cyclooctyne (DBCO) groups. Thus, bioorthogonal click reaction between the azide groups and the DBCO groups forms direct, stable, irreversible covalent bonds between the cellular integrin and the hydrogel. We demonstrate that the integrin-hydrogel linkage is in ON state regardless of the intensity of the stress, the cell cycle, or the extracellular environment, so that mechanical stress is rapidly and reliably transmitted to the nucleus through the linkage in vivo, resulting in regenerative response of the transplanted cells.
    DOI:  https://doi.org/10.1038/s41467-025-64656-9
  10. Sci Rep. 2025 Oct 13. 15(1): 35632
    Redefine tumor spheroids heterogeneity via PCA-coupled biophysical characterization.
    Domenico Andrea Cristaldi, Martina Bedeschi, Gianfranco Cavallaro, Azzurra Sargenti, Simone Pasqua, Simone Bonetti, Daniele Gazzola, Noemi Marino, Cosimo Gianluca Fortuna, Anna Tesei.
      Spheroids, a part of 3D cell culture systems, are crucial models for bridging in-vitro and in-human studies. However, achieving reliable standardization remains difficult, even when comparing spheroids of similar diameters. The challenge arises due to their cross-sectional architecture, which increases heterogeneity and affects biological outcomes. Here we present a novel solution that integrates Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) with Biophysical Characterization (PCA-BC). This approach allows for the identification and classification of variability within and across spheroid populations, offering insights into factors that contribute to heterogeneity. Additionally, it highlights the impact of different operators on spheroid development. The PCA-BC method enables real-time analysis of spheroid samples, facilitating the identification of variability across 3D populations. The integration of PCA and HCA with biophysical characterization provides a clear and efficient means to monitor sample heterogeneity. It also helps track how different operators influence the results, improving overall standardization in 3D cell cultures. By offering structural insights into spheroid heterogeneity, the PCA-BC approach supports more informed decision-making. This significantly improves workflow efficiency, conserving both time and resources, and enhances the reliability of 3D cell culture experiments.
    Keywords:  3D cell culture; Biophysical characterization; Mass density; Spheroids; Tumor models
    DOI:  https://doi.org/10.1038/s41598-025-19557-8
  11. Acta Biomater. 2025 Oct 15. pii: S1742-7061(25)00771-8. [Epub ahead of print]
    STRUCTURAL INSTABILITY OF THE SUPERFICIAL LAYERS OF THE FIBRINOGEN MATRIX CONTRIBUTES TO ITS NONADHESIVE PROPERTIES.
    Valeryi K Lishko, Aibek Mursalimov, Nataly P Podolnikova, Tatiana P Ugarova.
      Adsorption of fibrinogen on various surfaces, including biomaterials, significantly reduces adhesion of leukocytes and platelets. The mechanism by which fibrinogen renders surfaces nonadhesive involves its surface-induced self-assembly, resulting in the formation of a nanoscale multilayer matrix. Under static conditions, when tensile forces exerted by cellular integrins pull on the fibrinogen multilayer, it extends due to the separation of layers, preventing efficient mechanotransduction and leading to weak intracellular signaling and cell adhesion. Furthermore, a weak association between fibrinogen molecules in the superficial layers of the matrix allows integrins to pull fibrinogen molecules out of the matrix, causing the detachment of adherent cells. It remains unclear whether this process contributes to the anti-adhesive mechanism under flow when cells transiently contact the fibrinogen matrix. In the present study, using several flow systems, we demonstrated that various cells, including isolated blood cells, strip superficial fibrinogen molecules from the matrix, preventing their adhesion. Fibrinogen desorption in a cell-free buffer was significantly lower than that with cells. Surprisingly, the integrin fibrinogen receptors on cultured and primary leukocytes and platelets had minimal impact on fibrinogen detachment, as function-blocking anti-integrin antibodies did not significantly inhibit this process. Additionally, erythrocytes, which are not known to express specific fibrinogen receptors and even naked liposomes that can interact with fibrinogen with minimal affinity, caused fibrinogen detachment, suggesting that the stripping of superficial layers may arise from the low-affinity interactions of cells with the matrix. These results indicate that the peeling effect on the fibrinogen matrix exerted by cells under flow contributes to the anti-adhesive mechanism. STATEMENT OF SIGNIFICANCE: Adsorption of the blood protein fibrinogen on implanted vascular grafts is crucial for their clinical performance. Recent research shows that fibrinogen adsorption triggers its self-assembly, forming a nonadhesive multilayer matrix. The nonadhesive properties of this matrix under static conditions arise from layer separation, which occurs when cellular integrins pull on the matrix, reducing the mechanotransduction response and weakening cell adhesion. In this study, we reveal a new mechanism explaining why fibrinogen multilayer fails to support cell adhesion under flow. We demonstrate that flowing cells detach fibrinogen molecules that are loosely associated with the upper surface of the matrix, thereby preventing platelet and leukocyte adhesion. This work enhances our understanding of protective anti-adhesive mechanisms that the host develops after the implantation of biomaterials, which could inform the design of improved vascular grafts.
    Keywords:  Fibrinogen; adsorption; biomaterials; cell adhesion; desorption
    DOI:  https://doi.org/10.1016/j.actbio.2025.10.024
  12. Nat Synth. 2024 Aug;3(8): 943-957
    Applications of synthetic polymers directed toward living cells.
    Anqi Zhang, Spencer Zhao, Jonathan Tyson, Karl Deisseroth, Zhenan Bao.
      Cells execute remarkable functions using biopolymers synthesized from natural building blocks. Engineering cells to leverage the vast array of synthesizable abiotic polymers could provide enhanced or entirely new cellular functions. In this review, we discuss the applications of in situ synthesized abiotic polymers in three distinct domains: intracellular polymerization, cell surface polymerization, and extracellular polymerization. These advances have led to novel applications in various areas, such as cancer therapy, cell imaging, cellular activity manipulation, cell protection, and electrode assembly. Examples of these synthetic approaches can be applied across all domains of life, ranging from microbes and cultured mammalian cells to plants and animals. Finally, we discuss challenges and future opportunities in this emerging field, which could enable new synthetic approaches to influence biological processes and functions.
    DOI:  https://doi.org/10.1038/s44160-024-00560-2
  13. Sci Adv. 2025 Oct 17. 11(42): eadu3708
    Bubble-driven cell detachment.
    Bert Vandereydt, Baptiste Blanc, Kripa K Varanasi.
      On-demand cell detachment is of great importance in various applications in biosensitive environments. Existing methods such as enzymatic treatments and mechanical scraping are often time-consuming, labor-intensive, and harmful to cells. In this work, we demonstrate a method of detaching cells from substrates using electrochemical bubble generation without biocide generation. We demonstrate that shear stress generated by fluid flow beneath a rising bubble is the primary mechanism for cell detachment. This strategy, relying solely on physical forces and independent of cell or surface chemistry, can therefore work with a large range of the media, surfaces, and cells. We successfully implement this discovery at the lab-scale by designing a prototype for on-demand cell detachment that maintains high cell viability. The developed principle could find applications in high-throughput culture settings, such as algae photobioreactors or cell culture environments.
    DOI:  https://doi.org/10.1126/sciadv.adu3708
  14. Matrix Biol. 2025 Oct 09. pii: S0945-053X(25)00103-9. [Epub ahead of print]
    Laminin-511-functionalized fibrin gel enables in-gel proliferation of human induced pluripotent stem cells.
    Yukimasa Taniguchi, Mamoru Takizawa, Ayaka Hada, Ayano Ishimaru, Kiyotoshi Sekiguchi.
      Fibrin is a biocompatible hydrogel that is widely used as a surgical sealant and as a scaffold for in vitro cell culture. Here, we engineered a heterotrimeric chimera between fibrinogen and laminin-511 by connecting the N-terminal self-polymerization domain of fibrinogen with the C-terminal integrin-binding domain of laminin-511 via their coiled-coil regions. The resulting chimeric protein, designated Chimera-511, binds to fibrinogen in a thrombin-dependent manner and exerts integrin-binding activity in a fibrin(ogen)-bound form. Chimera-511 co-polymerizes with fibrinogen to form a fibrin gel endowed with the potent integrin-binding activity of laminin-511, thereby enabling robust three-dimensional proliferation of human induced pluripotent stem cells while maintaining their pluripotency marker expression and trilineage differentiation potential. This functionalized, biodegradable fibrin gel provides a defined and clinically compatible three-dimensional scaffold for stem cell culture, with potential applications in both basic research and regenerative medicine.
    Keywords:  3D culture; fibrin gel; integrin; laminin; pluripotent stem cell
    DOI:  https://doi.org/10.1016/j.matbio.2025.10.003
  15. Proc Natl Acad Sci U S A. 2025 Oct 21. 122(42): e2512977122
    Exploring bacteria-surface interactions with a fluorescent membrane tension probe.
    M Carmen Gonzalez-Garcia, Daniel Ballesteros, Jaime J Hernández, Manuel Pazos, Isabel Rodríguez, Jose Requejo-Isidro, Cristina Flors.
      Understanding how bacteria interact with surfaces is critical for advancing applications in biofilm and biofouling prevention, biomaterial development, or biosensing. However, the biophysical mechanisms underlying these interactions remain poorly characterized, and novel microscopy strategies are needed to specifically address the biointerface. In this study, we employ fluorescence lifetime imaging microscopy (FLIM) with the tension reporter Flipper-TR to investigate membrane tension in live bacteria interacting with various surfaces. We show that Flipper-TR stains both Gram-positive and Gram-negative bacterial membranes, exhibiting fluorescence lifetimes shorter than those in eukaryotic cells, with slight variations between bacterial types and likely reflecting differences in membrane composition. Flipper-TR displays lifetime variations along the vertical axis of bacterial cells, suggesting spatial differences in membrane tension influenced by cell wall architecture. Our results further demonstrate that Flipper-TR is responsive to the nature of bacterial interactions with surfaces. By comparing bacterial immobilization on surfaces with different coatings, we show that Flipper-TR can sensitively distinguish differences in membrane tension arising from distinct adhesion mechanisms. Additionally, Flipper-TR detects changes in membrane tension when bacteria are exposed to engineered nanostructured substrates. Overall, this work expands the toolbox to study the mechanical aspects of bacterial-material interactions and contributes to providing design rules for novel materials that influence bacterial behavior.
    Keywords:  bacteria; cell–material interface; fluorescence lifetime imaging; membrane tension probe; nanotopographies
    DOI:  https://doi.org/10.1073/pnas.2512977122
  16. Biomater Adv. 2025 Oct 13. pii: S2772-9508(25)00380-2. [Epub ahead of print]180 214553
    Bioactive and degradable peg hydrogels: A multifunctional approach for tissue regeneration and antibacterial protection.
    Patricia López-Gómez, Nabila Mehwish, Maria-Pau Ginebra, Carlos Mas-Moruno.
      Biomaterial-associated infections pose a significant challenge, impairing tissue integration and frequently leading to implant failure and revision surgeries. Upon implantation, host cells and bacteria compete for colonizing the implant, in a process known as the "race for the surface," which is critical for the long-term survival of the implant. However, conventional biomaterials commonly fail to simultaneously promote cellular integration and prevent infections. To address this issue, we developed a protease-degradable PEG hydrogel functionalized with the RGD integrin-binding motif to enhance cell adhesion and the antimicrobial peptide hLf1-11 (LF) to provide antibacterial activity. This hydrogel was crosslinked using a protease-sensitive peptide (VPM), enabling enzymatic degradation, and dynamic adaptation to the cellular microenvironment (PEG-RGDLF). Non-bioactive but degradable (PEG-50) and neither bioactive nor degradable (PEG-0) hydrogels were included as controls. PEG-RGDLF hydrogels showed an adequate internal structure, with well-defined porosity, swelling capacity, and protease-mediated degradation rate. PEG-RGDLF improved the adhesion, spreading, proliferation, and ALP activity of human bone marrow mesenchymal stem cells (hBMSCs) and reduced the viability and adhesion of Gram-positive and Gram-negative bacteria, significantly affecting their morphology. Furthermore, co-culture models were established under two clinically relevant scenarios: "pre-infection" and "post-infection". In both settings, PEG-RGDLF hydrogels supported enhanced cellular responses, with hBMSCs displaying an elongated morphology and improved adhesion. In summary, by integrating cell-instructive and antibacterial properties with a controlled degradation mechanism, this multifunctional hydrogel presents a robust platform for implant-based therapies, actively promoting tissue regeneration while preventing infection, thus addressing the persistent challenge of implant-associated infections in regenerative medicine and clinical applications.
    Keywords:  LF; PEG hydrogels; RGD; antibacterial peptide; cell adhesion; multifunctional hydrogel; protease-degradable hydrogels
    DOI:  https://doi.org/10.1016/j.bioadv.2025.214553
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