A sustained-release antibacterial gelatin hydrogel based on metal-phenolic networks for long-term preservation of prefabricated meat.

Spatiotemporal controlled disintegration enabling injected magnetic hydrogel for percutaneous hepatocellular carcinoma treatment.

Ionic thermoelectric poly(vinyl alcohol)/gelatin hydrogel for passive multimodal physiological sensing via the sol-gel transition triggered by salting out effect

Self-healing materials represent a paradigm shift in designing functional biomedical devices for drug delivery, tissue regeneration, and 3D bioprinting. However, their clinical translation remains limited by challenges such as insufficient mechanical strength, potential cytotoxicity from chemical modifications, and complex activation requirements. Here, we report the development of a self-healing colloidal gelatin hydrogel engineered as a flowable hemostatic matrix and successfully demonstrate its bench-to-bedside translation into a biomedical device (Colloidose). Specifically, amphoteric gelatin sub-microparticles self-assemble into an integrated gel network exhibiting a high storage modulus (G' > 15kPa) and a healing efficiency exceeding 95%, enabling rapid in situ solidification to accelerate blood clot formation. By benchmarking against conventional flowable matrices composed of coarse hundreds of micrometer-sized gelatin granules, we demonstrate that Colloidose offers superior hemostatic efficacy in anatomically challenging or pressure-intolerant sites (e.g., hepatobiliary, otorhinolaryngological, and gynecologic surgeries). Supported by comprehensive preclinical studies and over 300 clinical cases, Colloidose exemplifies the successful translation of an advanced self-healing biomaterial, establishing its role as a next-generation hemostat and opening new avenues for injectable and moldable biomedical devices.

Chronic disease-associated wounds pose significant challenges in suturing, encompassing knot-tying complexity in minimally invasive procedures, instability in edematous wounds, and unsatisfactory wound healing. Herein, we introduce a concept of near-infrared (NIR)-responsive shape-memory polymer (SMP) suture featuring dual functionality: NIR-triggered shape-memory recovery and on-demand drug delivery. The SMP suture is synthesized from poly(L-lactide) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Subsequently, it is modified with copper ion-chelated polydopamine (PDA-Cu2+) complexes and coated with a temperature-sensitive (∼42 °C) gelatin hydrogel. Upon exposure to NIR, the PDA-Cu2+complexes induce a rapid photothermal effect, which triggers noncontact self-tightening (∼25 s recovery time and near-complete shape recover) of the programmed suture with 80% pre-strain to accelerate wound closure. Meanwhile, the NIR-increased heat governs the "gel-sol" transition of the hydrogel that lowers suture's Tg to 51.46, enhances recovery force to ∼0.4 N and reduces suture friction force to ∼0.35 N, and initiates a "off-on" drug release. Such a NIR-responsive mechanism not only significantly improves fibroblast growth and functionality by enhancing cell-fiber interactions in vitro, but also mitigates inflammatory response and stimulates neovascularization to advance skin regeneration in vivo. Overall, this study develops an NIR-responsive SMP suture with noncontact self-tightening and controlled drug release, enabling on-demand therapeutic interventions for specific wound locations. STATEMENT OF SIGNIFICANCE: For chronic disease-related wounds, high-performance sutures with advanced biofunctionalities have been extensively explored to accelerate healing, as surgical sutures help wound closure while minimizing scar formation. Nevertheless, suturing such wounds remains challenging due to knot-tying complexity, instability in edematous tissue, and suboptimal clinical outcomes. Herein, we developed a near-infrared (NIR) responsive shape-memory polymer suture that integrates noncontact self-tightening and on-demand drug release. The smart suture can be pre-programmed and rapidly self-tightens upon NIR irradiation, thereby promoting wound closure. Concurrently, the photothermal effect triggered by NIR enables controlled drug release from the suture, which enhances cell-fiber interactions and facilitates incisional wound healing in targeted areas. This dual-functional design highlights its potential to provide spatially precise, on-demand therapies for specific wound regions.

Bacterial infections can delay wound healing and represent serious medical problems both in the hospital and community settings, especially skin wound infections caused by Staphylococcus aureus. In this work, a gelatin hydrogel modified with photo-cross-linkable methacrylamide groups at 10% concentration (GelMA10%), enriched with titanium dioxide nanoparticles (TiO2NPs), and loaded with Neomycin sulphate was developed with the aim to realize a tissue for wound care with improved mechanical and antimicrobial properties. TiO2 nanocomposite GelMA films with two concentrations of TiO2NPs were characterized to assess physicochemical, structural and mechanical properties by scanning electron microscopy equipped with an energy-dispersive X-ray spectrometer (SEM/EDX), micro-computed tomography (micro-CT) and X-ray photoelectron spectroscopy (XPS). TiO2 nanocomposite GelMA films showed a more compact structure, reduced pore sizes and a higher compressive modulus at the increasing concentration of TiO2NPs. They were able to absorb and retain water for a prolonged time; however, no significant differences in the swelling degree at the increasing concentration of TiO2NPs were observed. In vitro drug release and antibacterial activity against Staphylococcus aureus of TiO2 nanocomposite GelMA film enriched with higher concentrations of TiO2NPs, identified as a suitable candidate for wound healing, were investigated. Both GelMA10% and TiO2 nanocomposite GelMA films loaded with drug exhibited a strong antibacterial action, whereas GelMA10% containing only TiO2NPs did not show any antimicrobial properties.

Effects of growth factor application on germ cell architecture and oxidative stress handling in a rat model of testicular torsion-detorsion.

This article presents a step‑by‑step protocol to fabricate, supplement, and surgically apply an in situ blue‑light-crosslinkable gelatin hydrogel for corneal stromal wound repair in rabbits. The hydrogel precursor comprises gelatin at 5% (w/v) and riboflavin phosphate at 0.01% (w/v), prepared under sterile and light‑protected conditions, sterile‑filtered, and warmed before use to achieve injectable viscosity. Optional incorporation of human amniotic membrane extract or rabbit autologous serum is detailed. On‑demand gelation is triggered on the ocular surface using blue light at λ = 420-480 nm for a total of 2 min. The in vivo method includes a reproducible anterior stromal keratectomy (trephine diameter 6.5 mm; depth approximately 187 µm), followed by hydrogel filling, light activation, and a partial lateral tarsorrhaphy to stabilize the treatment, favor wound healing, and standardize postoperative care. Representative in vitro outcomes evidence gel‑like viscoelastic behavior with shear‑thinning and rapid recovery, and high optical transmittance (> 90%) beyond 500 nm, indicating suitability for corneal use. In vivo, hydrogel‑based treatments support progressive epithelial closure, good ocular tolerance (low Draize scores at 3 and 7 days), and time‑dependent loss of visible hydrogel consistent with biodegradation and tissue replacement. Critical steps and pause points are highlighted to ensure reproducibility, including temperature control during dissolution and filtration, protection from light, and lamp positioning during crosslinking. The protocol enables suture‑free, precisely placed, light‑activated hydrogel stabilization, compatible with the addition of multiple bioactive supplements. It provides a practical platform for preclinical evaluation of next‑generation ophthalmic biomaterials and facilitates translation of photo‑crosslinkable hydrogel therapies for corneal wound repair.

This study evaluated whether three-dimensional alginate–gelatin hydrogels (AGHs) crosslinked with calcium chloride (CaCl2) enhance the osteo-odontogenic differentiation of odontoblast-like cells in vitro. Two seeding configurations were compared: inter-hydrogel (INT) surface seeding and intra-hydrogel (INTR) encapsulation. Here, the MDPC-23 cells were cultured in AGHs crosslinked with 70 or 100 mM CaCl2 and assessed for proliferation, cytoskeletal morphology, alkaline phosphatase (ALPase) activity, osteo-odontogenic gene expression, and mineralized nodule formation. After 7 days, cell proliferation was significantly greater in the alginate–gelatin hydrogel (AGH) groups than in the control group. Cells in the intra alginate–gelatin hydrogel 100 (INTR-AGH100) remained predominantly rounded, whereas those in the inter alginate–gelatin hydrogel 100 (INT-AGH100) formed irregular clusters on the hydrogel surface. ALPase activity was highest in INTR-AGH100 at the early stage of culture. Both INT-AGH100 and INTR-AGH100 showed significantly increased expression of DSPP, DMP-1, BSP, OCN, OPN, and Runx-2, together with enhanced mineralized nodule formation. Although no significant differences were detected between the two seeding strategies in all assays, distinct morphological patterns were observed, and the INTR configuration showed relatively greater early differentiation-related activity. These findings suggest that 100 mM CaCl2-crosslinked AGHs provide a favorable three-dimensional microenvironment under the present experimental conditions and represent a promising in vitro scaffold platform to support future studies of scaffold-guided dentin regeneration.

Background/Objectives: Skin cancers belong to the most frequent cancer type with over a million cases per year. Presently, transdermal drug delivery systems (TDDS) are an attractive drug delivery route, but they still face some limitations due to the resistance of human skin. Methods: Here, Sonidegib, PEDOT:PSS, and gelatins were employed as the model drug, drug carrier, and drug matrix, respectively. Results: Gelatin hydrogels were fabricated via the physical crosslinking to avoid toxicity towards the human skin. PEDOT:PSS was synthesized by chemical oxidative polymerization as the drug carrier. Sonidegib first interacted with PEDOT:PSS before they were embedded into the gelatin hydrogels. In the release and release-permeation experiments, the amounts of Sonidegib released and permeated were investigated under the effects of gelatin types, concentrations, pH values, PEDOT:PSS, and electrical voltages. For the effect of gelatin types, the BG gelatin provided higher amounts of Sonidegib release than PG from the higher electrorepulsive force. Under applied electrical voltages and with PEDOT:PSS present, the amounts of Sonidegib release and release-permeation amounts increased as PEDOT:PSS assisted in providing higher electroosmosis and electrorepulsive forces. Conclusions: In summary, PEDOT:PSS in the BG hydrogel is demonstrated here as a potential drug carrier to improve the Sonidegib release and release-permeation iontophoretically for TDDS.

Small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) are emerging as potent acellular therapeutics; however, their rapid clearance hinders their clinical translation. To address this issue, 3D-bioprinted genipin-crosslinked gelatin (GECL) was engineered for human health. GECL hydrogels were functionalised with human umbilical cord MSC-derived sEVs (hUCMSC-sEVs) to create a bioactive wound-healing platform. These hydrogels demonstrated favourable physicochemical, mechanical, and biodegradable properties while providing an extracellular matrix (ECM)-mimetic environment conducive to tissue regeneration. MSCs were isolated from the umbilical cords, and their small extracellular vesicles (sEVs) were extracted and incorporated into gelatin-based hydrogels via 3D bioprinting. These sEV-loaded scaffolds were embedded in full-thickness wounds in mice, and healing was evaluated through macroscopic observation, histological analysis, collagen deposition, and angiogenesis assessment. Compared with the untreated controls, both the hydrogel-only (B) and sEV-loaded hydrogel (BE) groups significantly accelerated in vivo wound healing. Notably, the BE group achieved complete wound closure within 14 days, restoring the skin architecture, which closely resembled the native tissue with well-organised epidermal and dermal layers, optimal thickness, and skin appendages. Histological and ultrastructural assessments revealed an increased collagen type I deposition, a reduced α-smooth muscle actin (α-SMA) expression, and a robust neovascularisation. The TEM revealed tight junctions and active cellular infiltration, indicating scaffold integration and functional remodelling. Immunohistochemistry further revealed an upregulated CD31 expression with a balanced α-smooth muscle actin (α-SMA) expression, reflecting coordinated angiogenesis and myofibroblast regulation. These results highlight sEV-functionalised GECL hydrogels as robust and clinically translatable acellular therapeutic green products for accelerated wound closure and functional skin regeneration, advancing the fields of regenerative medicine and life expectancy.

Atom transfer radical polymerization (ATRP) is a controlled radical polymerization method that enables the synthesis of tailored polymeric materials with low dispersity, highlighting its immense potential for green fabrication of advanced materials. However, its broader implementation is limited by challenges in product isolation, maintaining catalyst activity, and mitigating atmospheric sensitivity arising from oxygen-sensitive metal catalysts. Here, gelatin hydrogels (GHs) are introduced as a soft "reactor" matrix for interfacial ATRP, operating with minimal metal-catalyst loading while exhibiting possibly an organoreductive behavior. This strategy leverages activator regeneration via electron transfer through a ligand-metal charge-transfer (LMCT) mechanism to reduce oxidized metal catalysts within the GH network. Polymerization is evaluated by growing polymer brushes at an active interface formed between GHs swollen in monomer solution and an initiating surface, and sequential growth experiments confirmed that GH-mediated ATRP preserves living character. Under UV illumination, LMCT is activated, producing polymers both at the desired interface and within the GH bulk. UV-Vis spectroscopy revealed active reduction of Cu(II) to Cu(I) along with concentration-dependent complex formation, indicating dynamic coordination chemistry within the hydrogel. The redox-active arginine- and glutamic acid-rich gelatin backbone coordinates and reduces the metal center, enabling ATRP at ppm-level catalyst concentrations. While polymerization proceeds in GH-Cu(II) reactors, adding external mobile ligands to the GH results in longer polymer brushes. The results reported here are exploratory. More experiments are needed to characterize polymer brush growth in GHs and compare it to conventional surface-initiated polymerization in solution.

Curcumin nanoparticles and mesenchymal stem cell exosomes embedded in gelatin hydrogel enhance healing of severe burns.

Development of pH-stimulus responsive gelatin hydrogel loaded with bacteriocin bifidocin A for salmon preservation.

Hierarchical periosteum-bone composite scaffold with staged release of dexamethasone and endothelial cell derivatives for efficient critical-sized bone defect repair.

Sustainable gelatin-carbon dot hydrogel coatings for fruit preservation: integrating antioxidant and antibacterial activities.

Functional iron oxide nanoparticles cross-linked hydrogel for craniofacial bone regeneration.

Halloysite and Zn2+-crosslinked gelatin/polyamidoxime-based hydrogel with immunoregulatory and antibacterial properties for promoting wound healing.

The development of tissue-engineered heart valves (TEHVs) remains a challenge worldwide. In this study, a series of double-crosslinked methacrylated (MA) carrageenan (CA)/MA gelatin hydrogels loaded with heparin (CA/Gel@Hep) were developed as potential materials for TEHV. CA/Gel@Hep hydrogels with different concentrations of heparin were fabricated, and their mechanical properties, swelling/degradation behaviors, and heparin release profiles, and biological performance were systematically studied. The rheological tests showed that storage modulus (G') was consistently higher than loss modulus (G''). Unconfined compression tests showed that the compressive modulus of CA/Gel@Hep hydrogels ranged from 0.26 ± 0.01 to 0.43 ± 0.03 kPa, which matches the mechanical requirements of native valve leaflets.In vitroevaluation demonstrated that CA/Gel@Hep hydrogels exhibited good cytocompatibility and blood compatibility, excellent anticoagulant properties, and facilitated migration and proliferation of human adipose tissue-derived mesenchymal stromal cells. quantitative PCR results showed that CA/Gel@Hep hydrogels significantly upregulated the expression of genes related to valve remodeling, including SMA, VIM, MMP1, and MMP2. These results suggest that CA/Gel@Hep hydrogels hold great potential for heart valve tissue engineering applications.

This study introduces a novel, one-step, extrusion-based printing strategy for fabricating zinc-infused hydrogels composed of oxidized alginate, gelatin, and polydopamine, eliminating the need for post-print crosslinking. The hydrogel forms a tri-modal crosslinked network comprising: (i) covalent Schiff base bonds between oxidized alginate and gelatin; (ii) Zn2+-mediated coordination with alginate carboxylates and PDA catechol groups; and (iii) non-covalent interactions such as hydrogen bonding and π–π stacking within the PDA-rich matrix. FTIR analysis confirmed the successful integration of these interactions, with characteristic peaks for C = N stretching (1640 cm−1), metal–ligand coordination (1420 and 1600 cm−1), and broad O–H/N–H absorption (3200–3500 cm−1), validating the tri-modal architecture. This integrated network provided enhanced structural integrity and rapid shape retention, as supported by rheological stability and extrusion performance of the final printed hydrogel. Systematic optimization of the Zn2+:PDA molar ratio identified 2:4 as optimal, achieving superior printability, viscoelasticity, and shear-thinning behavior. The optimized hydrogel (Zn2) exhibited high lap-shear adhesion (20 ± 4.4 kPa), strong antibacterial efficacy (77% against Escherichia coli), notable antioxidant activity (48%), and promoted fibroblast proliferation (128% viability at 72 h). By circumventing post-print treatments, this platform offers a rapid and scalable approach for producing extrusion-printable hydrogels with multifunctional properties, providing a promising basis for further development in tissue engineering applications.