A bioactive supramolecular and covalent polymer scaffold for cartilage repair in a sheep model.

Regeneration of hyaline cartilage in human-sized joints remains a clinical challenge, and it is a critical unmet need that would contribute to longer healthspans. Injectable scaffolds for cartilage repair that integrate both bioactivity and sufficiently robust physical properties to withstand joint stresses offer a promising strategy. We report here on a hybrid biomaterial that combines a bioactive peptide amphiphile supramolecular polymer that specifically binds the chondrogenic cytokine transforming growth factor ß-1 (TGFß-1) and crosslinked hyaluronic acid microgels that drive formation of filament bundles, a hierarchical motif common in natural musculoskeletal tissues. The scaffold is an injectable slurry that generates a porous rubbery material when exposed to calcium ions once placed in cartilage defects. The hybrid material was found to support in vitro chondrogenic differentiation of encapsulated stem cells in response to sustained delivery of TGFß-1. Using a sheep model, we implanted the scaffold in shallow osteochondral defects and found it can remain localized in mechanically active joints. Evaluation of resected joints showed significantly improved repair of hyaline cartilage in osteochondral defects injected with the scaffold relative to defects injected with the growth factor alone, including implantation in the load-bearing femoral condyle. These results demonstrate the potential of the hybrid biomimetic scaffold as a niche to favor cartilage repair in mechanically active joints using a clinically relevant large-animal model.

Chemical modification of hyaluronan oligosaccharides differentially modulates hyaluronan-hyaladherin interactions.

The glycosaminoglycan hyaluronan (HA) is a ubiquitous, nonsulfated polysaccharide with diverse biological roles mediated through its interactions with HA-binding proteins (HABPs). Most HABPs belong to the Link module superfamily, including the major HA receptor, CD44, and secreted protein TSG-6, which catalyzes the covalent transfer of heavy chains from inter-α-inhibitor onto HA. The structures of the HA-binding domains (HABDs) of CD44 (HABD_CD44) and TSG-6 (Link_TSG6) have been determined and their interactions with HA extensively characterized. The mechanisms of binding are different, with Link_TSG6 interacting with HA primarily via ionic and CH-π interactions, whereas HABD_CD44 binds solely via hydrogen bonds and van der Waals forces. Here, we exploit these differences to generate HA oligosaccharides, chemically modified at their reducing ends, that bind specifically and differentially to these target HABPs. Hexasaccharides (HA6AN) modified with 2- or 3-aminobenzoic acid (HA6-2AA, HA6-3AA) or 2-amino-4-methoxybenzoic acid (HA6-2A4MBA), had increased affinities for Link_TSG6 compared to unmodified HA6AN. These modifications did not increase the affinity for CD44_HABD. A model of HA6-2AA (derived from the solution dynamic 3D structure of HA4-2AA) was docked into the Link_TSG6 structure, providing evidence that the 2AA-carboxyl forms a salt bridge with Arginine-81. These modeling results informed a second series of chemical modifications for HA oligosaccharides, which again showed differential binding to the two proteins. Several modifications to HA4 and HA6 were found to convert the oligosaccharide into substrates for heavy chain transfer, whereas unmodified HA4 and HA6 are not. This study has generated valuable research tools to further understand HA biology.

Engineered matrices reveal stiffness-mediated chemoresistance in patient-derived pancreatic cancer organoids.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by its fibrotic and stiff extracellular matrix. However, how the altered cell/extracellular-matrix signalling contributes to the PDAC tumour phenotype has been difficult to dissect. Here we design and engineer matrices that recapitulate the key hallmarks of the PDAC tumour extracellular matrix to address this knowledge gap. We show that patient-derived PDAC organoids from three patients develop resistance to several clinically relevant chemotherapies when cultured within high-stiffness matrices mechanically matched to in vivo tumours. Using genetic barcoding, we find that while matrix-specific clonal selection occurs, cellular heterogeneity is not the main driver of chemoresistance. Instead, matrix-induced chemoresistance occurs within a stiff environment due to the increased expression of drug efflux transporters mediated by CD44 receptor interactions with hyaluronan. Moreover, PDAC chemoresistance is reversible following transfer from high- to low-stiffness matrices, suggesting that targeting the fibrotic extracellular matrix may sensitize chemoresistant tumours. Overall, our findings support the potential of engineered matrices and patient-derived organoids for elucidating extracellular matrix contributions to human disease pathophysiology.

Mechanobiology of Hyaluronan: Connecting Biomechanics and Bioactivity in Musculoskeletal Tissues.

Hyaluronan (HA) plays well-recognized mechanical and biological roles in articular cartilage and synovial fluid, where it contributes to tissue structure and lubrication. An understanding of how HA contributes to the structure of other musculoskeletal tissues, including muscle, bone, tendon, and intervertebral discs, is growing. In addition, the use of HA-based therapies to restore damaged tissue is becoming more prevalent. Nevertheless, the relationship between biomechanical stimuli and HA synthesis, degradation, and signaling in musculoskeletal tissues remains understudied, limiting the utility of HA in regenerative medicine. In this review, we discuss the various roles and significance of endogenous HA in musculoskeletal tissues. We use what is known and unknown to motivate new lines of inquiry into HA biology within musculoskeletal tissues and in the mechanobiology governing HA metabolism by suggesting questions that remain regarding the relationship and interaction between biological and mechanical roles of HA in musculoskeletal health and disease.

Designable Nanoadaptor for Enhanced Recognition of Natural Killer Cell to Tumor via Bio-orthogonal Click Reaction.

Highly efficient recognition of cancer cells by immune cells is important for successful therapeutic-cell-based cancer immunotherapy. Herein, we present a facile NIR-II nanoadaptor [hyaluronic acid (HA)/dibenzocyclooctyne (DBCO)-Au:Ag2Te quantum dots (QDs)] for enhancing the tumor recognition and binding ability of natural killer (NK) cells via a bio-orthogonal click reaction in vivo. The Nanoadaptor possesses superior tumor-targeting capacity, facilitating the accumulation of the chemical receptor DBCO at the tumor sites. Subsequently, the enrichment of DBCO on tumor cell surfaces provides multivalent recognition sites for capturing pretreated azide engineered NK92 cells (NK92-N3) through an efficient click reaction, thereby significantly enhancing the therapeutical efficiency. The dynamic process of nanoadaptor-mediated recognition of NK cells to tumor cells could be vividly observed using multiplexed NIR-II fluorescence imaging in a mouse model of lung cancer. Such a nanoadaptor strategy can be extended to other therapeutic cellular systems and holds promise for future clinical applications.

Extracellular vimentin is sufficient to promote cell attachment, spreading, and motility by a mechanism involving N-acetyl glucosamine-containing structures.

Vimentin intermediate filaments form part of the cytoskeleton of mesenchymal cells, but under pathological conditions often associated with inflammation, vimentin filaments depolymerize as the result of phosphorylation or citrullination, and vimentin oligomers are secreted or released into the extracellular environment. In the extracellular space, vimentin can bind surfaces of cells and the extracellular matrix, and the interaction between extracellular vimentin and cells can trigger changes in cellular functions, such as activation of fibroblasts to a fibrotic phenotype. The mechanism by which extracellular vimentin binds external cell membranes and whether vimentin alone can act as an adhesive anchor for cells is largely uncharacterized. Here, we show that various cell types (normal and vimentin null fibroblasts, mesenchymal stem cells, and A549 lung carcinoma cells) attach to and spread on polyacrylamide hydrogel substrates covalently linked to vimentin. Using traction force microscopy and spheroid expansion assays, we characterize how different cell types respond to extracellular vimentin. Cell attachment to and spreading on vimentin-coated surfaces is inhibited by hyaluronic acid degrading enzymes, hyaluronic acid synthase inhibitors, soluble heparin or N-acetyl glucosamine, all of which are treatments that have little or no effect on the same cell types binding to collagen-coated hydrogels. These studies highlight the effectiveness of substrate-bound vimentin as a ligand for cells and suggest that carbohydrate structures, including the glycocalyx and glycosylated cell surface proteins that contain N-acetyl glucosamine, form a novel class of adhesion receptors for extracellular vimentin that can either directly support cell adhesion to a substrate or fine-tune the glycocalyx adhesive properties.

A novel anti-pruritic: Topical co-administration of high molecular weight hyaluronan (HMWH) with protamine, a transdermal transport enhancer.

Pruritis, the sensation of itch, is produced by multiple substances, exogenous and endogenous, that sensitizes specialized sensory neurons (pruriceptors and pruri-nociceptors). Unfortunately, many patients with acute and chronic pruritis obtain only partial relief when treated with currently available treatment modalities. We recently demonstrated that the topical application of high molecular weight hyaluronan (HMWH), when combined with vehicles containing transdermal transport enhancers, produce potent long-lasting reversal of nociceptor sensitization associated with inflammatory and neuropathic pain. In the present experiments we tested the hypothesis that the topical formulation of HMWH with protamine, a transdermal transport enhancer, can also attenuate pruritis. We report that this topical formulation of HMWH markedly attenuates scratching behavior at the nape of the neck induced by serotonin (5-hydroxytryptamine, 5-HT), in male and female rats. Our results support the hypothesis that topical HMWH in a transdermal transport enhancer vehicle is a strong anti-pruritic.

Targeted Analysis of the Size Distribution of Heavy Chain-Modified Hyaluronan with Solid-State Nanopores.

The glycosaminoglycan hyaluronan (HA) plays important roles in diverse physiological functions where the distribution of its molecular weight (MW) can influence its behavior and is known to change in response to disease conditions. During inflammation, HA undergoes a covalent modification in which heavy chain subunits of the inter-alpha-inhibitor family of proteins are transferred to its structure, forming heavy chain-HA (HC•HA) complexes. While limited assessments of HC•HA have been performed previously, determining the size distribution of its HA component remains a challenge. Here, we describe a selective method for extracting HC•HA from mixtures that yields material amenable to MW analysis with a solid-state nanopore sensor. After demonstrating the approach in vitro, we validate extraction of HC•HA from osteoarthritic human synovial fluid as a model complex biological matrix. Finally, we apply our technique to pathophysiology by measuring the size distributions of HC•HA and total HA in an equine model of synovitis.

Hyaluronic acid-modified mesoporous silica nanoprobes for target identification of atherosclerosis.

Rupture of vulnerable plaque and secondary thrombosis caused by atherosclerosis are one of the main causes of acute cardiovascular and cerebrovascular events, and it is urgent to develop an in-situ, noninvasive, sensitive and targeted detection method at molecular level. We chose CD44, a specific receptor highly expressed on the surface of macrophages, as the target of the molecular probe, and modified the CD44 ligand HA onto the surface of Gd2O3@MSN, constructing the MRI imaging nanoprobe HA-Gd2O3@MSN for targeted recognition of atherosclerosis. The fundamental properties of HA-Gd2O3@MSN were initially investigated. The CCK-8, hemolysis, hematoxylin-eosin staining tests and blood biochemical assays confirmed that HA-Gd2O3@MSN possessed excellent biocompatibility. Laser confocal microscopy, cellular magnetic resonance imaging, flow cytometry and immunohistochemistry were used to verify that the nanoprobes had good targeting properties. The in vivo targeting performance of the nanoprobes was further validated by employing a rabbit atherosclerosis animal model. In summary, the synthesized HA-Gd2O3@MSN nanoprobes have excellent biocompatibility properties as well as good targeting properties. It could provide a new technical tool for early identification of atherosclerosis.

Laminin and hyaluronan supplementation of collagen hydrogels enhances endothelial function and tight junction expression on three-dimensional cylindrical microvessel-on-a-chip.

Vasculature-on-chip (VoC) models have become a prominent tool in the study of microvasculature functions because of their cost-effective and ethical production process. These models typically use a hydrogel in which the three-dimensional (3D) microvascular structure is embedded. Thus, VoCs are directly impacted by the physical and chemical cues of the supporting hydrogel. Endothelial cell (EC) response in VoCs is critical, especially in organ-specific vasculature models, in which ECs exhibit specific traits and behaviors that vary between organs. Many studies customize the stimuli ECs perceive in different ways; however, customizing the hydrogel composition accordingly to the target organ's extracellular matrix (ECM), which we believe has great potential, has been rarely investigated. We explored this approach to organ-specific VoCs by fabricating microvessels (MVs) with either human umbilical vein ECs or human brain microvascular ECs in a 3D cylindrical VoC using a collagen hydrogel alone or one supplemented with laminin and hyaluronan, components found in the brain ECM. We characterized the physical properties of these hydrogels and analyzed the barrier properties of the MVs. Barrier function and tight junction (ZO-1) expression improved with the addition of laminin and hyaluronan in the composite hydrogel.

Scale-Dependent Rheology of Synovial Fluid Lubricating Macromolecules.

Synovial fluid (SF) is the complex biofluid that facilitates the exceptional lubrication of articular cartilage in joints. Its primary lubricating macromolecules, the linear polysaccharide hyaluronic acid (HA) and the mucin-like glycoprotein proteoglycan 4 (PRG4 or lubricin), interact synergistically to reduce boundary friction. However, the precise manner in which these molecules influence the rheological properties of SF remains unclear. This study aimed to elucidate this by employing confocal microscopy and multiscale rheometry to examine the microstructure and rheology of solutions containing recombinant human PRG4 (rhPRG4) and HA. Contrary to previous assumptions of an extensive HA-rhPRG4 network, it is discovered that rhPRG4 primarily forms stiff, gel-like aggregates. The properties of these aggregates, including their size and stiffness, are found to be influenced by the viscoelastic characteristics of the surrounding HA matrix. Consequently, the rheology of this system is not governed by a single length scale, but instead responds as a disordered, hierarchical network with solid-like rhPRG4 aggregates distributed throughout the continuous HA phase. These findings provide new insights into the biomechanical function of PRG4 in cartilage lubrication and may have implications in the development of HA-based therapies for joint diseases like osteoarthritis.

Chiral Supramolecular Nanofibers Regulated Tumor-Derived Exosomes Secretion for Constructing an Anti-Tumor Extracellular Microenvironment.

Tumor-derived exosomes (TDEs) induced extracellular microenvironment has recently been validated to be critical for tumor progression and metastasis, however, remodeling it for oncotherapy still remains a major challenge due to difficulty in regulation of TDEs secretion. Herein, the supramolecular chiral nanofibers, composed of L/D-phenylalanine derivates (L/D-Phe) and linear hyaluronic acid (HA), are successfully employed to construct TDEs induced anti-tumor extracellular microenvironment. The left-handed L-Phe @HA nanofibers significantly inhibit TDEs secretion into extracellular microenvironment, which results in suppression of tumor proliferation and metastasis in vitro and vivo. Biological assays and theoretical modeling reveal that these results are mainly attributed to strong adsorption of the key exosomes transporters (Ras-related protein Rab-27A and synaptosome-associated protein 23) on left-handed L-Phe @HA nanofibers via enhanced stereoselective interaction, leading to degradation and phosphorylated dropping of exosomes transporters. Subsequently, transfer function of exosomes transporters is limited, which causes remarkable inhibition of TDEs secretion. These findings provide a promising novel insight of chiral functional materials to establish an anti-tumor extracellular microenvironment via regulation of TDEs secretion.

Synergistic Effect of Ferroptosis-Inducing Nanoparticles and X-Ray Irradiation Combination Therapy.

Ferroptosis, characterized by the induction of cell death via lipid peroxidation, has been actively studied over the last few years and has shown the potential to improve the efficacy of cancer nanomedicine in an iron-dependent manner. Radiation therapy, a common treatment method, has limitations as a stand-alone treatment due to radiation resistance and safety as it affects even normal tissues. Although ferroptosis-inducing drugs help alleviate radiation resistance, there are no safe ferroptosis-inducing drugs that can be considered for clinical application and are still in the research stage. Here, the effectiveness of combined treatment with radiotherapy with Fe and hyaluronic acid-based nanoparticles (FHA-NPs) to directly induce ferroptosis, considering the clinical applications is reported. Through the induction of ferroptosis by FHA-NPs and apoptosis by X-ray irradiation, the therapeutic efficiency of cancer is greatly improved both in vitro and in vivo. In addition, Monte Carlo simulations are performed to assess the physical interactions of the X-rays with the iron-oxide nanoparticle. The study provides a deeper understanding of the synergistic effect of ferroptosis and X-ray irradiation combination therapy. Furthermore, the study can serve as a valuable reference for elucidating the role and mechanisms of ferroptosis in radiation therapy.

Lubricating Microneedles System with Multistage Sustained Drug Delivery for the Treatment of Osteoarthritis.

Osteoarthritis (OA) is a typical joint degenerative disease that is prevalent worldwide and significantly affects the normal activities of patients. Traditional treatments using diclofenac (DCF) as an anti-inflammatory drug by oral administration and transdermal delivery have many inherent deficiencies. In this study, a lubricating microneedles (MNs) system for the treatment of osteoarthritis with multistage sustained drug delivery and great reduction in skin damage during MNs penetration is developed. The bilayer dissolvable MNs system, namely HA-DCF@PDMPC, is prepared by designating the composite material of hyaluronic acid (HA) and covalently conjugated drug compound (HA-DCF) as the MNs tips and then modifying the surface of MNs tips with a self-adhesive lubricating copolymer (PDMPC). The MNs system is designed to achieve sustained drug release of DCF via ester bond hydrolysis, physical diffusion from MNs tips, and breakthrough of lubrication coating. Additionally, skin damage is reduced due to the presence of the lubrication coating on the superficial surface. Therefore, the lubricating MNs with multistage sustained drug delivery show good compliance as a transdermal patch for OA treatment, which is validated from anti-inflammatory cell tests and therapeutic animal experiments, down-regulating the expression levels of pro-inflammatory factors and alleviating articular cartilage destruction.

Surface Engineering of Natural Killer Cells with CD44-targeting Ligands for Augmented Cancer Immunotherapy.

Adoptive immunotherapy utilizing natural killer (NK) cells has demonstrated remarkable efficacy in treating hematologic malignancies. However, its clinical intervention for solid tumors is hindered by the limited expression of tumor-specific antigens. Herein, lipid-PEG conjugated hyaluronic acid (HA) materials (HA-PEG-Lipid) for the simple ex-vivo surface coating of NK cells is developed for 1) lipid-mediated cellular membrane anchoring via hydrophobic interaction and thereby 2) sufficient presentation of the CD44 ligand (i.e., HA) onto NK cells for cancer targeting, without the need for genetic manipulation. Membrane-engineered NK cells can selectively recognize CD44-overexpressing cancer cells through HA-CD44 affinity and subsequently induce in situ activation of NK cells for cancer elimination. Therefore, the surface-engineered NK cells using HA-PEG-Lipid (HANK cells) establish an immune synapse with CD44-overexpressing MIA PaCa-2 pancreatic cancer cells, triggering the "recognition-activation" mechanism, and ultimately eliminating cancer cells. Moreover, in mouse xenograft tumor models, administrated HANK cells demonstrate significant infiltration into solid tumors, resulting in tumor apoptosis/necrosis and effective suppression of tumor progression and metastasis, as compared to NK cells and gemcitabine. Taken together, the HA-PEG-Lipid biomaterials expedite the treatment of solid tumors by facilitating a sequential recognition-activation mechanism of surface-engineered HANK cells, suggesting a promising approach for NK cell-mediated immunotherapy.

Reactive Oxygen-Correlated Photothermal Imaging of Smart COF Nanoreactors for Monitoring Chemodynamic Sterilization and Promoting Wound Healing.

Chemodynamic therapy (CDT) has emerged as a promising approach for treating infected diabetic wounds, while reliable imaging technology for simultaneous monitoring of ROS and therapeutic processes is still a formidable challenge. Herein, smart covalent organic framework (COF) nanoreactors (COF NRs) are constructed by hyaluronic acid (HA) packaged glucose oxidase (GOx) covalently linked Fe-COF for diabetic wound healing. Upon the breakdown of the HA protective layer, GOx consumes glucose to produce gluconic acid and hydrogen peroxide (H2O2), resulting in decreased local pH and H2O2 supplementation. Density functional theory (DFT) calculations show that Fe-COF has high catalytic activity towards H2O2, leading to in situ generation of hydroxyl radicals (·OH) for sterilization, and the localized downregulation of glucose effectively improved the microenvironment of diabetic wounds. Meanwhile, based on the near-infrared photothermal imaging of oxidized 3,3',5,5'-tetramethylbenzidine (oxTMB), the authors showed that TMB can be applied for the point-of-care testing of ·OH and glucose, and assessing the sterilization progress in vivo. More significantly, the facile photothermal signaling strategy can be extended to monitor various ROS-mediated therapeutic systems, enabling accurate prediction of treatment outcomes.

Study of Iron Complex Photosensitizer with Hollow Double-Shell Nano Structure Used to Enhance Ferroptosis and Photodynamic Therapy.

Ferroptosis therapy, which uses ferroptosis inducers to produce lethal lipid peroxides and induce tumor cell death, is considered a promising cancer treatment strategy. However, challenges remain regarding how to increase the accumulation of reactive oxygen species (ROS) in the tumor microenvironment (TME) to enhance antitumor efficacy. In this study, a hyaluronic acid (HA) encapsulated hollow mesoporous manganese dioxide (H-MnO2) with double-shell nanostructure is designed to contain iron coordinated cyanine near-infrared dye IR783 (IR783-Fe) for synergistic ferroptosis photodynamic therapy against tumors. The nano photosensitizer IR783-Fe@MnO2-HA, in which HA actively targets the CD44 receptor, subsequently dissociates and releases Fe3+ and IR783 in acidic TME. First, Fe3+ consumes glutathione to produce Fe2+, which promotes the Fenton reaction in cells to produce hydroxyl free radicals (·OH) and induce ferroptosis of tumor cells. In addition, MnO2 catalyzes the production of O2 from H2O2 and enhances the production of singlet oxygen (1O2) by IR783 under laser irradiation, thus increasing the production and accumulation of ROS to provide photodynamic therapy. The highly biocompatible IR783-Fe@MnO2-HA nano-photosensitizers have exhibited tumor-targeting ability and efficient tumor inhibition in vivo due to the synergistic effect of photodynamic and ferroptosis antitumor therapies.

A Stimulus-Responsive Ternary Heterojunction Boosting Oxidative Stress, Cuproptosis for Melanoma Therapy.

Cuproptosis, a recently discovered copper-dependent cell death, presents significant potential for the development of copper-based nanoparticles to induce cuproptosis in cancer therapy. Herein, a unique ternary heterojunction, denoted as HACT, composed of core-shell Au@Cu2O nanocubes with surface-deposited Titanium Dioxide quantum dots and modified with hyaluronic acid is introduced. Compared to core-shell AC NCs, the TiO2/Au@Cu2O exhibits improved energy structure optimization, successfully separating electron-hole pairs for redox use. This optimization results in a more rapid generation of singlet oxygen and hydroxyl radicals triggering oxidative stress under ultrasound radiation. Furthermore, the HACT NCs initiate cuproptosis by Fenton-like reaction and acidic environment, leading to the sequential release of cupric and cuprous ions. This accumulation of copper induces the aggregation of lipoylated proteins and reduces iron-sulfur proteins, ultimately initiating cuproptosis. More importantly, HACT NCs show a tendency to selectively target cancer cells, thereby granting them a degree of biosecurity. This report introduces a ternary heterojunction capable of triggering both cuproptosis and oxidative stress-related combination therapy in a stimulus-responsive manner. It can energize efforts to develop effective melanoma treatment strategies using Cu-based nanoparticles through rational design.

Enhancing Endogenous Hyaluronic Acid in Osteoarthritic Joints with an Anti-Inflammatory Supramolecular Nanofiber Hydrogel Delivering HAS2 Lentivirus.

Osteoarthritis (OA) management remains challenging because of its intricate pathogenesis. Intra-articular injections of drugs, such as glucocorticoids and hyaluronic acid (HA), have certain limitations, including the risk of joint infection, pain, and swelling. Hydrogel-based therapeutic strategies have attracted considerable attention because of their enormous therapeutic potential. Herein, a supramolecular nanofiber hydrogel is developed using dexamethasone sodium phosphate (DexP) as a vector to deliver lentivirus-encoding hyaluronan synthase 2 (HAS2) (HAS2@DexP-Gel). During hydrogel degradation, HAS2 lentivirus and DexP molecules are slowly released. Intra-articular injection of HAS2@DexP-Gel promotes endogenous HA production and suppresses synovial inflammation. Additionally, HAS2@DexP-Gel reduces subchondral bone resorption in the anterior cruciate ligament transection-induced OA mice, attenuates cartilage degeneration, and delays OA progression. HAS2@DexP-Gel exhibited good biocompatibility both in vitro and in vivo. The therapeutic mechanisms of the HAS2@DexP-Gel are investigated using single-cell RNA sequencing. HAS2@DexP-Gel optimizes the microenvironment of the synovial tissue by modulating the proportion of synovial cell subpopulations and regulating the interactions between synovial fibroblasts and macrophages. The innovative nanofiber hydrogel, HAS2@DexP-Gel, effectively enhances endogenous HA production while reducing synovial inflammation. This comprehensive approach holds promise for improving joint function, alleviating pain, and slowing OA progression, thereby providing significant benefits to patients.

Enhancing Cell Aggregation and Migration via Double-Click Cross-Linking with Azide-Modified Hyaluronic Acid.

We present a novel approach to the formation of cell aggregates by employing click chemistry with water-soluble zwitterionic dibenzo cyclooctadiyne (WS-CODY) and azide-modified hyaluronic acid (HA-N3) as a linker to facilitate rapid and stable cell aggregation. By optimizing the concentrations of HA-N3 and WS-CODY, we achieved efficient cross-linking between azide-modified cell surfaces and HA-N3, generating cell aggregates within 10 min, and the resulting aggregates remained stable for up to 5 days, with cell viability maintained at approximately 80%. Systematic experiments revealed that a stoichiometric balance between HA-N3 and WS-CODY is important for effective cross-linking, highlighting the roles of both cell-surface azide modification and HA in the aggregate formation. We also investigated the genetic basis of altered cell behavior within these aggregates. Transcriptome analysis (RNA-seq) of aggregates postcultivation revealed a marked fluctuation of genes associated with 'cell migration' and 'cell adhesion', including notable changes in the expression of HYAL1, ICAM-1, CEACAM5 and RHOB. These findings suggest that HA-N3-mediated cell aggregation can induce intrinsic cellular responses that not only facilitate cell aggregate formation but also modulate cell-matrix interactions. We term this phenomenon 'chemo-resilience', The simplicity and efficacy of this click chemistry-based approach suggest it may have broad applicability for forming cell aggregates and modulating cell-matrix interactions in tissue engineering and regenerative medicine.