bims-ecemfi 2025-05-18 papers

bims-ecemfi

Biomed News

on ECM and fibroblasts

Issue of 2025–05–18
fifteen papers selected by
Badri Narayanan Narasimhan, University of California, San Diego

Stable and oscillatory hypoxia differentially regulate invasibility of breast cancer associated fibroblasts.
Engineered Hydrogels for Organoid Models of Human Nonalcoholic Fatty Liver Disease.
Collagen Fiber Density Observed in Metastatic Ovarian Cancer Promotes Tumor Cell Adhesion.
Mechanically and Chemically Defined PEG Hydrogels Improve Reproducibility in Human Cardioid Development.
Mesenchymal Stromal Cell Chondrogenic Differentiation Induced by Continuous Stiffness Gradient in Photocrosslinkable Hydrogels.
Microfluidic-assisted engineering of hydrogels with microscale complexity.
Viscous dissipation in the rupture of cell-cell contacts.
Dual-Dynamic Covalently Cross-Linked Polyglycerol Hydrogels for Tumor Spheroid Culture.
Structural and Mechanical Characterization of Collagen-Hyaluronan Hydrogels Used to Study Cancer Cell Invasion through the Bladder Wall.
Computationally enabled polychromatic polarized imaging enables mapping of matrix architectures that promote pancreatic ductal adenocarcinoma dissemination.
Supramolecular peptidic dopants for inducing photoconductivity and mechanical tunability in digital light processable hydrogels.
E-cadherin mechanotransduction activates EGFR-ERK signaling in epithelial monolayers by inducing ADAM-mediated ligand shedding.
Rapid closure and hemostasis of ruptured soft tissues using a modified human tropoelastin-based sealant in preclinical models.
Measuring Matrix Metalloproteinases Activity by Gelatin Zymography.
Reversible Stiffening of Biopolymeric Hybrid Networks by Dynamically Switching Cross-Links In Situ.

Mechanobiol Med. 2024 Sep;pii: 100070. [Epub ahead of print]2(3):

Stable and oscillatory hypoxia differentially regulate invasibility of breast cancer associated fibroblasts.

Wenqiang Du, Ashkan Novin, Yamin Liu, Junaid Afzal, Shaofei Liu, Yasir Suhail, Kshitiz.

As local regions in the tumor outstrip their oxygen supply, hypoxia can develop, affecting not only the cancer cells, but also other cells in the microenvironment, including cancer associated fibroblasts (CAFs). Hypoxia is also not necessarily stable over time, and can fluctuate or oscillate. Hypoxia Inducible Factor-1 is the master regulator of cellular response to hypoxia, and can also exhibit oscillations in its activity. To understand how stable, and fluctuating hypoxia influence breast CAFs, we measured changes in gene expression in CAFs in normoxia, hypoxia, and oscillatory hypoxia, as well as measured change in their capacity to resist, or assist breast cancer invasion. We show that hypoxia has a profound effect on breast CAFs causing activation of key pathways associated with fibroblast activation, but reduce myofibroblast activation and traction force generation. We also found that oscillatory hypoxia, while expectedly resulted in a "sub-hypoxic" response in gene expression, it resulted in specific activation of pathways associated with actin polymerization and actomyosin maturation. Using traction force microscopy, and a nanopatterned stromal invasion assay, we show that oscillatory hypoxia increases contractile force generation vs stable hypoxia, and increases heterogeneity in force generation response, while also additively enhancing invasibility of CAFs to MDA-MB-231 invasion. Our data show that stable and unstable hypoxia can regulate many mechnobiological characteristics of CAFs, and can contribute to transformation of CAFs to assist cancer dissemination and onset of metastasis.

DOI: https://doi.org/10.1016/j.mbm.2024.100070
Adv Sci (Weinh). 2025 May 14. e17332

Engineered Hydrogels for Organoid Models of Human Nonalcoholic Fatty Liver Disease.

Yueming Liu, Aidan E Gilchrist, Patrik K Johansson, Yuan Guan, Jaydon D Deras, Yu-Chung Liu, Sofia Ceva, Michelle S Huang, Renato S Navarro, Annika Enejder, Gary Peltz, Sarah C Heilshorn.

  Nonalcoholic fatty liver disease (NAFLD) is characterized by increased lipid accumulation and excessive deposition of extracellular matrix (ECM) that results in tissue stiffening. The potential interplay between matrix stiffness and hepatocyte lipid accumulation during NAFLD has not been established. Here, an in vitro NAFLD model is developed using chemically defined, engineered hydrogels and human induced pluripotent stem cell-derived hepatic organoids (HOs). Specifically, dynamic covalent chemistry crosslinking, along with transient small molecule competitors, are used to create dynamic stiffening hydrogels that enable the reproducible culture of HOs. Within matrices that mimic the stiffness of healthy to diseased tissue (≈1-6 kPa), lipid droplet accumulation in HOs is triggered by exposure to an NAFLD-associated free fatty acid. These NAFLD model suggests that higher stiffness microenvironments result in increased hepatic lipid droplet accumulation, increased expression of fibrosis markers, and increased metabolic dysregulation. By targeting the ROCK mechanosignaling pathway, the synergy between matrix stiffness and lipid droplet accumulation is disrupted. The in vitro model of NAFLD has the potential to understand the role of mechanosignaling in disease progression and identify new pathways for therapeutic intervention.

Keywords:  engineered hydrogels; hepatic organoids; lipid accumulation; matrix stiffening; mechanosignaling

DOI:  https://doi.org/10.1002/advs.202417332
Acta Biomater. 2025 May 13. pii: S1742-7061(25)00360-5. [Epub ahead of print]

Collagen Fiber Density Observed in Metastatic Ovarian Cancer Promotes Tumor Cell Adhesion.

Ali Abbaspour, Ana L Martinez Cavazos, Roshan Patel, Ning Yang, Stephanie McGregor, Erin G Brooks, Kristyn S Masters, Pamela K Kreeger.

  Collagen type I, a key structural component of the extracellular matrix (ECM), is frequently altered in cancer, with altered fiber organization at the primary tumor site linked to metastasis and poor patient outcomes. Here, we demonstrate that collagen fibers are also altered in metastatic sites such as the omentum of patients with high-grade serous ovarian cancer (HGSOC). Specifically, we observed a significant increase in fiber density, alignment, and width. To determine if the increase in fiber density supports metastasis, we used a semi-interpenetrating methacrylated gelatin (gelMA) network in combination with increasing fibrillar collagen. Cancer cells had significantly increased adhesion as collagen fiber density increased. To determine the responsible mechanisms, we used orthogonal systems to examine 1) the different adhesion peptides exposed in collagen (GFOGER) and gelatin (RGD), and 2) the physical structure of fibers. Cells had minimal response to GFOGER, either alone or in combination with RGD, suggesting that increased adhesion did not result from this collagen-specific interaction. Cell adhesion was significantly higher on electrospun PCL-gelatin fibers compared to flat PCL-gelatin substrates, suggesting that increased cell adhesion resulted from fiber structure. We next investigated the cellular mechanisms involved in increased adhesion on gelMA/coll and found that actin polymerization, but not myosin II contractility, was needed. We further demonstrated that cells on fibrous gels had more robust actin polymerization, and that this resulted in greater adhesion strength. Combined, these results suggest that the increase in collagen fibers with tumor metastasis will support the development of additional metastases. STATEMENT OF SIGNIFICANCE: This work advances the evaluation of the matrisome of the omentum, the most common metastatic site in advanced ovarian cancer by characterizing how collagen fibers change with disease progression. To examine the effect of collagen fibers on metastasis, we utilized a suite of in vitro biomaterials to identify a novel role for collagen fibers in supporting cell adhesion through increased actin dynamics during nascent adhesion formation, which results in increased adhesion strength at later times.

Keywords:  HGSOC; actin polymerization; cell adhesion; collagen fibers; gelMA

DOI:  https://doi.org/10.1016/j.actbio.2025.05.035
Adv Healthc Mater. 2025 May 16. e2403997

Mechanically and Chemically Defined PEG Hydrogels Improve Reproducibility in Human Cardioid Development.

Yuanhui Song, Michael Seitz, Andrew Kowalczewski, Nhu Y Mai, Era Jain, Huaxiao Yang, Zhen Ma.

  Cardioids are 3D self-organized heart organoids directly derived from induced pluripotent stem cells (hiPSCs) aggregates. The growth and culture of cardioids is either conducted in suspension culture or heavily relies on Matrigel encapsulation. Despite the significant advancements in cardioid technology, reproducibility remains a major challenge, limiting their widespread use in both basic research and translational applications. Here, for the first time, we employed synthetic, matrix metalloproteinase (MMP)-degradable polyethylene glycol (PEG)-based hydrogels to define the effect of mechanical and biochemical cues on cardioid development. Successful cardiac differentiation is demonstrated in all the hydrogel conditions, while cardioid cultured in optimized PEG hydrogel (3 wt.% PEG-2mM RGD) underwent similar morphological development and comparable tissue functions to those cultured in Matrigel. Matrix stiffness and cell adhesion motif play a critical role in cardioid development, nascent chamber formation, contractile physiology, and endothelial cell gene enrichment. More importantly, synthetic hydrogel improved the reproducibility in cardioid properties compared to traditional suspension culture and Matrigel encapsulation. Therefore, PEG-based hydrogel has the potential to be used as an alternative to Matrigel for human cardioid culture in a variety of clinical applications including cell therapy and tissue engineering.

Keywords:  cardioids; human induced pluripotent stem cells; mechanobiology; organoids; synthetic hydrogel

DOI:  https://doi.org/10.1002/adhm.202403997
J Biomed Mater Res A. 2025 May;113(5): e37928

Mesenchymal Stromal Cell Chondrogenic Differentiation Induced by Continuous Stiffness Gradient in Photocrosslinkable Hydrogels.

Sabrina C Mierswa, Erika E Wheeler, Ayla N Apsey, Oju Jeon, Eben Alsberg, J Kent Leach.

  Chondrogenic differentiation of stem and progenitor cells is dependent on the biophysical properties of the surrounding matrix. Current biomaterials-based approaches for chondrogenesis are limited to discrete platforms, slowing our ability to interrogate the role of mechanical cues such as substrate stiffness and other signals. Thus, novel platforms must incorporate a range of biophysical properties within a single construct to effectively assess changes in cell response. We encapsulated human mesenchymal stromal cells (MSCs) within biodegradable, photocurable oxidized, and methacrylated alginate (OMA). Cell-laden hydrogels were crosslinked when exposed to light through a grayscale photomask to form substrates with a continuous stiffness gradient. We also tested the influence of the adhesive ligand Arg-Gly-Asp (RGD) on chondrogenic differentiation. Compared to unmodified gels possessing uniform biophysical properties, RGD-modified OMA hydrogels with the same modulus promoted chondrogenic differentiation of MSCs as evidenced by gene expression, matrix deposition, and histological analysis. MSCs entrapped in OMA hydrogels exhibiting a biologically relevant stiffness gradient (2-13 kPa over 8 mm) demonstrated increased chondrogenic differentiation with increases in stiffness. MSC chondrogenic differentiation was dependent upon the ability to mechanosense the modulus of the surrounding matrix, confirmed by the addition of Latrunculin A (LatA), a soluble inhibitor of actin polymerization. These findings validate a methodology for customizing hydrogel platforms for chondrogenic differentiation and identifying the interplay of key variables to instruct cell function.

Keywords:  chondrogenesis; gradient; mesenchymal stromal cell; photocrosslinking; stiffness

DOI:  https://doi.org/10.1002/jbm.a.37928
Acta Biomater. 2025 May 09. pii: S1742-7061(25)00350-2. [Epub ahead of print]

Microfluidic-assisted engineering of hydrogels with microscale complexity.

Yuehong Li, Danyang Huang, Yuting Zhang, Yun Xiao, Xingdong Zhang.

  Hydrogels have emerged as a promising 3D cell culture scaffold owing to their structural similarity to the extracellular matrix (ECM) and their tunable physicochemical properties. Recent advances in microfluidic technology have enabled the fabrication of hydrogels into precisely controlled microspheres and microfibers, which serve as modular units for scalable 3D tissue assembly. Furthermore, advances in 3D bioprinting have allowed facile and precise spatial engineering of these hydrogel-based structures into complex architectures. When integrated with microfluidics, these systems facilitate microscale heterogeneity, dynamic shear flow, and gradient generation-critical features for advancing organoids and organ-on-a-chip systems. In this review, we will discuss (1) microfluidic strategies for the preparation of hydrogel microspheres and microfibers, (2) the integration of microfluidics with 3D bioprinting technologies, and (3) their transformative applications in organoids and organ-on-a-chip systems. STATEMENT OF SIGNIFICANCE: Microfluidic-assisted preparation and assembly of hydrogel microspheres and microfibers have enabled unprecedented precision in size, morphology and compositional control. The diverse configurations of these hydrogel modules offer the opportunities to generate 3D constructs with microscale complexity-recapitulating critical features of native tissues such as compartmentalized microenvironments, cellular gradients, and vascular networks. In this review, we discuss the fundamental microfluidic principles governing the generation of hydrogel microspheres (0D) and microfibers (1D), their hierarchical assembly into 3D constructs, and their integration with 3D bioprinting platforms to generate and culture organoids and organ-on-a-chip systems. The synergistic integration of microfluidics and bioprinting overcomes longstanding limitations of conventional 3D culture, such as static microenvironments and poor spatial resolution. Advances in microfluidic design offer tunable hydrogel biophysical and biochemical properties that regulate cell behaviors dynamically. Looking forward, the growing mastery of these principles paves the way for next-generation organoids and organ-on-a-chip systems with improved cellular heterogeneity, integrated vasculature, and multicellular crosstalk, closing the gap between in vitro models and human pathophysiology.

Keywords:  3D bioprinting; Hydrogel; Microfluidics; Microspheres; Organ-on-a-chip

DOI:  https://doi.org/10.1016/j.actbio.2025.05.023
Nat Mater. 2025 May 12.

Viscous dissipation in the rupture of cell-cell contacts.

Aditya Arora, Mohd Suhail Rizvi, Gianluca Grenci, Florian Dilasser, Chaoyu Fu, Modhura Ganguly, Sree Vaishnavi, Kathirvel Paramsivam, Srikanth Budnar, Ivar Noordstra, Alpha S Yap, Virgile Viasnoff.

Cell-cell adhesions mediated by adherens junctions, structures connecting cells to each other and to the cortical cytoskeleton, are essential for epithelial physical and biological integrity. Nonetheless, how such structures resist mechanical stimuli that prompt cell-cell rupture is still not fully understood. Here we challenge the conventional views on cell-cell adhesion stability, highlighting the importance of viscous dissipation at the cellular level. Using microdevices to measure the rupture energy of cell-cell junctions and synthetic cadherins to discriminate cadherin binding energy from downstream cytoskeletal regulation, we demonstrate that the balance between cortical tension and cell shape recovery time determines a transition from ductile to brittle fracture in cell-cell contact. These findings suggest that junction toughness, defined as the junction disruption energy, is a more accurate measure of junctional stability, challenging the current emphasis on bond energy and tension. Overall, our results highlight the role and the regulation of energy dissipation through the cytoskeleton during junction deformation for epithelial integrity.

DOI: https://doi.org/10.1038/s41563-025-02232-8
Biomacromolecules. 2025 May 10.

Dual-Dynamic Covalently Cross-Linked Polyglycerol Hydrogels for Tumor Spheroid Culture.

Jun Feng, Polina Ponomareva, Kunpeng Liu, Chuanxiong Nie, Rui Chen, Rainer Haag.

Advancing cancer research depends significantly on developing accurate and reliable models that can replicate the complex tumor microenvironment. Tumor spheroids─three-dimensional clusters of cancer cells─have become crucial tools for this purpose. The overarching goal of tumor spheroid culture is to develop biomaterials that mimic the dynamic mechanical behavior of the native extracellular matrix, enabling high-fidelity culture models. In this study, we developed dynamic hydrogels based on dual-dynamic covalently cross-linked polyglycerol, using boronate bonds and Schiff-base interactions. In addition to good biocompatibility and long-term stability, the hydrogels showed tunable mechanical properties that enabled cells to actively remodel their surrounding microenvironment. This platform was used for successful 3D culture of various cancer cell lines, including HeLa, A549, HT-29, BT-474, and SK-BR-3, which were encapsulated in situ and formed 3D tumor spheroids. These results demonstrate the feasibility and versatility of our dynamic hydrogel system in supporting tumor spheroid culture.

DOI: https://doi.org/10.1021/acs.biomac.4c01744
ACS Biomater Sci Eng. 2025 May 15.

Structural and Mechanical Characterization of Collagen-Hyaluronan Hydrogels Used to Study Cancer Cell Invasion through the Bladder Wall.

Sara Metwally, Justyna Śmiałek-Bartyzel, Joanna Pabijan, Małgorzata Lekka.

  Collagen-hyaluronic acid (Col-HA) hydrogels are widely studied as biomimetic materials that recapitulate the environmental physical and mechanical properties crucial for understanding the cell behavior during cancer invasion and progression. Our research focused on Col-HA hydrogels as an environment to study the invasion of bladder cancer cells through the bladder wall. The bladder is a heterogeneous structure composed of three main layers: urothelium (the softest), lamina propria (the stiffest), and the muscle outer layer, with elastic properties lying between the two. Thus, the bladder cancer cells migrate through the mechanically distinct environments. We investigated the impact of Col-HA hydrogel microstructure and rheology on migrating bladder cancer T24 cells from the cancer spheroid surface to the surrounding environment formed from various collagen I and HA concentrations and chemical structures. The designed hydrogels showed variability in network density and rheological properties. The migration of bladder cancer cells was inhibited inside hydrogels of ∼1 kPa storage modulus. The correlation analysis showed that collagen concentration primarily defined the rheological properties of Col-HA hydrogels, but hydrogels can soften or stiffen depending on the type of HA used. Within soft Col-HA hydrogels, cells freely invade the surrounding environment, while its stiffening impedes cell movement and almost inhibits cell migration. Only individual, probably leading, cells are observed at the spheroid edges initiating the invasion. Our findings showed that the rheological properties of the hydrogels dominate in regulating cancer cell migration, providing a platform to study how bladder cancer cells migrate through the heterogeneous structure of the bladder wall.

Keywords:  bladder cancer; collagen; hyaluronic acid; hydrogel structure and rheology; hydrogels

DOI:  https://doi.org/10.1021/acsbiomaterials.5c00136
Am J Pathol. 2025 May 09. pii: S0002-9440(25)00160-9. [Epub ahead of print]

Computationally enabled polychromatic polarized imaging enables mapping of matrix architectures that promote pancreatic ductal adenocarcinoma dissemination.

Guhan Qian, Hongrong Zhang, Yuming Liu, Michael Shribak, Kevin W Eliceiri, Paolo P Provenzano.

Pancreatic ductal adenocarcinoma (PDA) is an extremely metastatic and lethal disease. In PDA, extracellular matrix (ECM) architectures known as Tumor-Associated Collagen Signatures (TACS) regulate invasion and metastatic spread in both early dissemination and in late-stage disease. As such, TACS has been suggested as a biomarker to aid in pathologic assessment. However, despite its significance, approaches to quantitatively capture these ECM patterns currently require advanced optical systems with signaling processing analysis. Here we present an expansion of polychromatic polarized microscopy (PPM) with inherent angular information coupled to machine learning and computational pixel-wise analysis of TACS. Using this platform, we are able to accurately capture TACS architectures in H&E stained histology sections directly through PPM contrast. Moreover, PPM facilitated identification of transitions to dissemination architectures, i.e., transitions from sequestration through expansion to dissemination from both PanINs and throughout PDA. Lastly, PPM evaluation of architectures in liver metastases, the most common metastatic site for PDA, demonstrates TACS-mediated focal and local invasion as well as identification of unique patterns anchoring aligned fibers into normal-adjacent tumor, suggesting that these patterns may be precursors to metastasis expansion and local spread from micrometastatic lesions. Combined, these findings demonstrate that PPM coupled to computational platforms is a powerful tool for analyzing ECM architecture that can be employed to advance cancer microenvironment studies and provide clinically relevant diagnostic information.

DOI: https://doi.org/10.1016/j.ajpath.2025.04.017
Faraday Discuss. 2025 May 14.

Supramolecular peptidic dopants for inducing photoconductivity and mechanical tunability in digital light processable hydrogels.

Harrison C Jeong, Yuyao Kuang, Ze-Fan Yao, Herdeline Ann M Ardona.

This work presents a strategy for generating composite hydrogels bearing photoconductive conduits held by supramolecular interactions that are compatible with digital light processing (DLP) printing. Conductive polymers are typically processed with organic solvents as the film, yet if used as biomaterials, excitable cells often require matching with the mechanical and structural properties of their native, aqueous three-dimensional (3-D) microenvironment. Here, we utilize peptide-functionalized porphyrin units capable of self-assembling into photoconductive nanostructures with defined nanomorphologies under aqueous conditions. In addition to the DXXD peptide arms (X = V, F), the sequence variants studied here include a peptidic moiety bearing allyloxycarbonyl (alloc) groups that can serve as crosslinking sites of the acrylate-based monomers that ultimately form the base 3-D covalent network for the hydrogels. We investigate the impact of pre-templating polymeric gelators with supramolecular assemblies vs. printing a dispersed peptide-porphyrin in a polymer composite, specifically, the potential impact of the morphologies of the supramolecular additives or "dopants" on the resulting mechanical property, conductivity, and printability of the hydrogels, comprised of a hybrid between acrylated polymers and supramolecular peptide-porphyrin assemblies. Lastly, we demonstrate the role of photophysical properties that emerge from peptide-tuned porphyrin assemblies as a photoabsorber additive that influences the printing outcomes of the composite hydrogel. Overall, we present a covalent-supramolecular composite hydrogelator system where the self-assembled networks offer a pathway for energy transport and mechanical reinforcement/dissipation at the same time, leading to the formation of a hydrogel with optoelectronic, mechanical, and printable behavior that can be influenced by self-assembled dopants.

DOI: https://doi.org/10.1039/d5fd00031a
Sci Signal. 2025 May 13. 18(886): eadr7926

E-cadherin mechanotransduction activates EGFR-ERK signaling in epithelial monolayers by inducing ADAM-mediated ligand shedding.

Ronja M Houtekamer, Mirjam C van der Net, Marjolein J Vliem, Tomas E J C Noordzij, Lisa van Uden, Robert M van Es, Joo Yong Sim, Eriko Deguchi, Kenta Terai, Matthew A Hopcroft, Harmjan R Vos, Beth L Pruitt, Michiyuki Matsuda, Willem-Jan Pannekoek, Martijn Gloerich.

The behavior of cells is governed by signals originating from their local environment, including mechanical forces exerted on the cells. Forces are transduced by mechanosensitive proteins, which can impinge on signaling cascades that are also activated by growth factors. We investigated the cross-talk between mechanical and biochemical signals in the regulation of intracellular signaling networks in epithelial monolayers. Phosphoproteomic and transcriptomic analyses on epithelial monolayers subjected to mechanical strain revealed the activation of extracellular signal-regulated kinase (ERK) downstream of the epidermal growth factor receptor (EGFR) as a predominant strain-induced signaling event. Strain-induced EGFR-ERK signaling depended on mechanosensitive E-cadherin adhesions. Proximity labeling showed that the metalloproteinase ADAM17, an enzyme that mediates shedding of soluble EGFR ligands, was closely associated with E-cadherin. A probe that we developed to monitor ADAM-mediated shedding demonstrated that mechanical strain induced ADAM activation. Mechanically induced ADAM activation was essential for mechanosensitive, E-cadherin-dependent EGFR-ERK signaling. Together, our data demonstrate that mechanical strain transduced by E-cadherin adhesion triggers the shedding of EGFR ligands that stimulate downstream ERK activity. Our findings illustrate how mechanical signals and biochemical ligands can operate within a linear signaling cascade.

DOI: https://doi.org/10.1126/scisignal.adr7926
Sci Transl Med. 2025 May 14. 17(798): eadr6458

Rapid closure and hemostasis of ruptured soft tissues using a modified human tropoelastin-based sealant in preclinical models.

Mahsa Ghovvati, Saumya Jain, George Z Cheng, Naoki Kaneko, Joshua A Boys, Taichiro Imahori, Tess De Maeseneer, Reihaneh Haghniaz, Robert B Cameron, Anthony S Weiss, Nasim Annabi.

Treatment of injuries to soft elastic organs is often hindered by challenging anatomical features and limitations of existing sealant materials, which may lack adequate tissue adhesion, elasticity, biocompatibility, and effective hemostatic properties. To address these clinical challenges, we developed an injectable elastic sealant formulated with methacryloyl-modified human recombinant tropoelastin (MeTro) and Laponite silicate nanoplatelets (SNs). We optimized the hydrogel formulation for mechanical properties, adhesion, biocompatibility, and hemostatic properties and used visible light for cross-linking to improve safety. MeTro/SN hydrogels had increased tissue adhesion strength and burst pressure in vitro and ex vivo compared with MeTro alone or commercial sealants. The addition of SNs to the hydrogels facilitated faster blood clotting in vitro without increasing hemolysis. Applied to incisional injuries on rat lungs or aortas, MeTro/SN had burst pressures comparable to those of native tissue and greater than those of MeTro after a 7-day in vivo application. On porcine lungs, MeTro/SN also supported effective lung sealing and burst pressure similar to native lung 14 days after injury sealing. In a rodent tail hemostasis model, MeTro/SN reduced bleeding compared with MeTro. In an injured porcine lung model, early hemostasis was better than the tested commercial sealants. The results demonstrated that MeTro/SN provided effective tissue sealing and promoted hemostasis in a time frame that minimized blood loss without causing a major inflammatory response. These findings highlight the translational potential of our engineered sealant with biomimetic mechanics, durable tissue adhesion, and rapid hemostasis as a multipronged approach for the sealing and repair of traumatic injuries to soft organs.

DOI: https://doi.org/10.1126/scitranslmed.adr6458
Methods Mol Biol. 2025 ;2917 65-74

Measuring Matrix Metalloproteinases Activity by Gelatin Zymography.

Kelli C Micocci, Uliana S Stotzer, Milene N O Moritz.

  Gelatin zymography is a widely popular method due to its simplicity, low cost, and quick results, for studying gelatinases in various biological systems. Zymography can detect both the pro and active forms of matrix metalloproteinases MMP-2 (gelatinase A) and MMP-9 (gelatinase B). These MMPs play critical roles in the pathophysiology of many human diseases, particularly in cancer progression. Gelatin zymography is a method based on a suitable protein substrate incorporated into a sodium dodecyl sulfate-polyacrylamide gel. Substrate degradation by protease-containing samples can be visualized through the contrast between the Coomassie blue-stained gel and the white band of substrate degradation. Here, we provide a straightforward, step-by-step methodology for detecting MMP-2 and MMP-9 gelatinases in tumor cells. It is essential to highlight that accurately interpreting the data requires a thorough understanding of the technique's principles.

Keywords:  Cell culture; Gelatin; MMP-2; MMP-9; Matrix metalloproteinases; Zymography

DOI:  https://doi.org/10.1007/978-1-0716-4478-2_6
ACS Appl Mater Interfaces. 2025 May 13.

Reversible Stiffening of Biopolymeric Hybrid Networks by Dynamically Switching Cross-Links In Situ.

Jana T Reh, Sebastian Voigt, Leonard R Gareis, Ufuk Gürer, Stephan A Sieber, Berna Özkale, Oliver Lieleg.

  Achieving reversible stiffening of biopolymer networks in a controlled manner remains a challenging topic in materials science, especially when trying to assess the following changes in mechanical material properties in real time. To address these challenges, we here utilize a custom-made measurement setup that allows us to manipulate the cross-linking state of alginate-based hydrogels in situ while quantifying the achieved alterations in the viscoelastic response of the biopolymer networks. Interpolymer connections in the biopolymer networks are created by a combination of light-induced, covalent cross-links, ionic cross-links, and DNA-based cross-links, where the latter two can be successfully removed again by employing either chelating agents (e.g., ethylenediaminetetraacetic acid and citrate) or suitable displacement DNA strands. In part, this range of the different cross-linking options mentioned is inter alia made possible by incorporating the glycoprotein mucin into the alginate system, which also allows for a range of different starting (∼0.2-400 Pa), intermediate (∼25 Pa-1.6 kPa), and final stiffnesses (∼4 Pa-1.2 kPa) of the mixed hydrogel matrix. At the same time, the presence of mucins (1-4% (w/v)) in the biopolymer mixture enhances the properties of the cytocompatible hydrogel by improving its antibacterial characteristics. Such well-controllable alginate/mucin networks with dynamically switchable mechanical properties will likely find broad applications in cell cultivation studies or tissue engineering applications.

Keywords:  antibacterial; biopolymer; hydrogels; reversible cross-links; tunable stiffness

DOI:  https://doi.org/10.1021/acsami.5c03419