Search Results (114)

Photocrosslinked gelatin methacryloyl/methacrylated chitosan (GelMA/CSMA) hydrogels are attractive for biomedical applications but are limited by insufficient mechanical strength. Here, γ-methacryloxypropyltrimethoxysilane (MPTS) was prehydrolyzed and condensed to generate siloxane species retaining polymerizable methacrylate groups, which were subsequently incorporated into the GelMA/CSMA network as a reinforcing phase. The effects of MPTS precursor concentration (2–5% w/v) and prehydrolysis time (12–48 h) on the morphology, viscoelasticity, compressive behavior, cytocompatibility, and DLP printability of the resulting GCM hydrogels were systematically investigated. FTIR confirmed methoxy-group consumption while retaining C=C functionality. SEM showed that increasing MPTS precursor concentration increased the apparent abundance of granular features, whereas prolonged prehydrolysis produced larger structures. XRD indicated a predominantly amorphous MPTS-derived phase. GCM-48 h-5% achieved a storage modulus of 23.5 kPa, compressive modulus of 0.682 MPa, and maximum compressive stress of 1.081 MPa, corresponding to 7.4-, 16.9-, and 4.0-fold increases over the GelMA/CSMA control, respectively. The hydrogels exhibited favorable L929 cytocompatibility and retained DLP printability under 405 nm irradiation. These findings demonstrate that regulating MPTS precursor concentration and prehydrolysis time provides a simple route to mechanically reinforce DLP-printable GelMA/CSMA hydrogels without directly incorporating preformed silica particles. Full article

Modulating the physical crosslink architecture of gelatin methacryloyl (GelMA) hydrogels without altering total polymer concentration or introducing exogenous components remains a central challenge in biomaterial design. Here, we present a source blending strategy in which porcine skin gelatin (PG) and salmon skin gelatin (SG), two gelatins with markedly different proline and hydroxyproline contents, are combined at seven compositional ratios (PG weight fractions 0–1.0) and subsequently functionalized to GelMA under standardized conditions (8% v/v methacrylic anhydride, 60 °C, 3 h). Near-complete degrees of substitution (95–98%) were achieved across all formulations, as confirmed by both TNBS and ¹H-NMR analyses. In the parent gelatin mixtures, increasing PG fraction progressively increased viscosity, elastic modulus (G′), gelation temperature (Tgel), and compression modulus at 4 °C, with DSC revealing independent SG (0–15 °C) and PG (20–40 °C) endothermic transitions that suggest partial hindrance of PG triple-helix formation by high SG fractions. These composition-dependent trends were preserved after functionalization to GelMA, albeit with attenuated physical crosslinking due to steric impairment by the methacrylate groups. Photocrosslinked GelMA hydrogels fabricated after pre-incubation at 4 °C exhibited systematically higher compression moduli and lower swelling degrees with increasing PG content, demonstrating that the PG/SG ratio provides an effective means for independently tuning hydrogel mechanics and mesh architecture. In vitro release assays using Rhodamine 6G further demonstrated that pre-incubation at 4 °C prior to photocrosslinking effectively modulates transport kinetics in SG-PG GelMA hydrogels. This strategy delayed characteristic release times and constrained Weibull shape parameters to the anomalous-transport regime (0.75 < β < 1), where diffusion is governed by network chain relaxation. This effect was most pronounced in the 0.4SG:0.6PG formulation, where lower SG content permitted unhindered triple-helix formation, as corroborated by DSC and compression studies. Ultimately, adjusting the pre-incubation temperature and gelatin source combination provides a straightforward, processing-additive-free strategy to achieve programmable release profiles via controlled matrix tortuosity. Full article

Background/Objectives: Osteoporosis poses significant obstacles as it causes an imbalance between osteoblasts and adipocytes, which results in the disruption of bone homeostasis. Although various magnesium-based scaffolds have been deployed for the treatment of osteoporotic bone defects, whether this can be achieved by alleviating bone–fat imbalance still requires further elucidation. Methods: We designed magnesium phosphate-based platforms (GMPCs), based on magnesium photopolymerized methacrylated gelatin (GelMA) and phosphate (K-struvite, MPC), and used them to deliver magnesium ions (Mg²⁺) for alleviating bone–fat imbalance locally. Results: The in vivo results demonstrated that the GMPCs not only improved osteogenic behavior at the implanted site, but also reduced the proportion of adipose tissues in a femoral defect model in 18-month-old SD rats. Moreover, by promoting the differentiation of bone marrow mesenchymal stem cells (BMSCs) into osteoblasts in a concentration-dependent manner, GMPCs significantly reduced adipogenic differentiation in vitro. Also, 5GMPC demonstrated the best comprehensive biologic properties compared to other platforms. Conclusions: GMPCs have great potential in the treatment of age-related osteoporosis via the effective delivery of Mg²⁺. Full article

Gelatin functionalized with methacrylate (GelMA), norbornene (GelNB), and phenol (GelPH) has been studied as a precursor for crosslinkable biomaterials in tissue engineering. Cytocompatibility is usually assessed post-hydrogel formation, but cells briefly encounter soluble precursors during preparation and residual functional groups that may remain post-gelation. However, the biological effects of these uncrosslinked derivatives remain poorly understood. This study systematically investigated the impact of functional group chemistry on cellular responses under uncrosslinking conditions. Four cell lines, including fibroblasts (BALB/3T3), cervical cancer cells (HeLa), mesenchymal stem cells (UE7T-13), and neuronal cells (PC-12), were exposed to soluble GelMA, GelNB, and GelPH at matched polymer concentrations and degrees of functionalization (~50%). The results showed no overt cytotoxicity. The detectable differences were subtle and strongly cell type-dependent. HeLa and PC-12 cells showed no clear differences from untreated controls in most parameters. BALB/3T3 fibroblasts showed mainly GelMA-associated differences in mitochondrial activity, proliferation, and morphology. In the UE7T-13 cells, GelMA-treated cells showed the largest deviations from controls across the readouts examined, including mitochondrial activity, cell area, phenotype-related gene expression, and some osteogenic markers, while GelPH was intermediate and GelNB was comparable to controls. These findings underscore the importance of considering residual precursor effects in gelatin-based biomaterial design. Full article

Chronic wounds, particularly those complicated by infection, present significant challenges in clinical management. The microenvironment of these wounds is typically characterized by the accumulation of reactive oxygen species (ROS) and abnormal local pH levels, both of which impede the healing process. Baicalin (BA), a natural flavonoid, exhibits anti-inflammatory activity, ROS-scavenging capability, and pro-healing effects. In this study, hydrogels were synthesized through photoinitiated radical polymerization of methacrylic anhydride (MAA) and dopamine (DA)-modified chondroitin sulfate (ChSMA-DA), grafting degrees of MA and DA were 58%, 23%, MPDA@MnO₂ nanoparticles (NPs), and methacrylated gelatin (GelMA). The gelation time, microtopography, swelling behavior, and water retention of the hydrogels were investigated, along with their degradation, rheological properties, and photothermal effects. The results indicate that swelling ratio (SR) and water retention (WR) of optimal HG-MPDA@MnO₂-M sample were 5.7, 82.42%, exhibited responsive behavior upon weakly acidic environment with pH 6.5 and elevated ROS levels, and exhibited a stable photothermal effect (photothermal conversion efficiency was 22.7%) under 808 nm near-infrared (NIR) light. Following the incorporation of the drug model BA, the cumulative release percentage over 24 h under the combined stimulation of pH 6.5, 1 mmol·L⁻¹ H₂O₂, and 808 nm NIR was 81.1%, significantly higher than either factor alone. These hydrogels show promise as an injectable dressing for chronic wounds, effectively integrating the internal microenvironment of the wound tissue with external NIR to modulate drug release. Full article

Gelatin methacrylate (GelMA) hydrogels are promising carriers for bioactive agents like curcumin (Cur) and adenosine diphosphate (ADP) in wound healing. However, existing GelMA-based systems fail to achieve both rapid hemostasis and sustained anti-inflammatory effects. In this study, we developed a Cur/ADP GelMA hydrogel, and evaluated its anti-inflammatory, regenerative, hemostatic, and biocompatible properties. Proton nuclear magnetic resonance (¹H-NMR) analysis showed that a 65% degree of substitution of GelMA is optimal for wound dressings. Scanning electron microscopy revealed a uniform pore size, aiding inflammatory exudate removal. The Cur/ADP GelMA hydrogel exhibited strong adhesion, stability, and antibacterial activity, reducing E. coli and S. aureus proliferation by 85% and 72%, respectively. Hemostatic effects were observed, with blood loss reduced to 238 ± 23 mg compared to 559 ± 18 mg in the untreated group. The ELISA results showed reduced pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) and increased IL-10. In vivo studies demonstrated 98% wound closure by day 14, enhanced granulation tissue formation, and a 70% thicker epidermis compared to controls. Mechanistically, ADP accelerates platelet activation and clot formation, while Cur modulates the inflammatory microenvironment, enabling synergistic hemostasis and immune regulation, thus promoting accelerated wound healing. Full article

Electrical monitoring of brain activity can be performed discreetly and continuously over long periods of time using intra-auricular electroencephalography (intra-auricular EEG), a promising technique suitable for subjects who are difficult to monitor, such as newborns or patients with neurological conditions requiring discreet but long-term neurophysiological assessment. The concept of intra-aural EEG can be realized through the development of systems that include wearable sensors, whose performance critically depends on the development of biocompatible electrode materials that exhibit low impedance and can maintain and provide stable contact between the electrode and the epithelial tissue. Based on our previous work on carbon nanotube (CNT)-based hydrogel composites for intra-aural EEG electrodes, this study focuses on the electrochemical characterization of hydrogels initially prepared from gelatin methacrylate (GelMA)/2-hydroxyethyl methacrylate (HEMA) doped with varying concentrations of CNTs (0–3 wt%). In the present study, the materials obtained in the first stage were evaluated using electrochemical impedance spectroscopy (EIS) under both liquid and dry conditions, supplemented by measurements of hydration capacity. The results show that the composite with 3% CNT content exhibits suitable properties, making the material making the 3 wt% CNT formulation a promising platform for the further development of 3D-printable hydrogel electrodes for intra-aural EEG applications. Equivalent circuit modeling reveals improved ionic and electronic conductivity compared to the undoped hydrogel, attributed to better CNT dispersion and polymer crosslinking. This work provides insights into the structure–property relationships of CNT–hydrogel composites and lays the foundation for the further development of a 3D-printed and in vitro/in vivo validated prototype of intra-aural EEG sensors. Full article

Cartilage regeneration remains an unmet clinical challenge. Despite the great advances in the production of hydrogels as support matrices for cartilage regeneration, the resulting mechanical properties remain low. Granular composite hydrogels appear as ideal candidates due to their injectability and modularity in design. Here, we report on the fabrication and characterization of heterogeneous composite granular hydrogels based on methacrylated chitosan (CHIMA) and gelatin (GelMA) microparticles supported by an interstitial methacrylated alginate (ALMA) matrix. Microparticles were prepared by an oil-emulsion method and their size and morphology optimized, resulting in CHIMA and GelMA microparticles of 10.8 µm (95% CI 9.2, 13.1) and 115.8 µm (95% CI 107.5, 137.6) in diameter, respectively. The microparticles were mixed with ALMA and crosslinked to form granular hydrogels that demonstrated reduced swelling and weight loss. The storage modulus increased from 33 to 66.4 kPa for CHIMA/ALMA hydrogels and from 11.5 to 19.5 kPa for GelMA/ALMA hydrogels when the particle concentration increased from 10 to 50%, and was higher than traditional ALMA hydrogels. Hydrogels of 50:50 CHIMA:GelMA permitted a 6.6-fold increase in cell number after 28 days of culture, and promoted the chondrogenic differentiation of embedded mouse mesenchymal stem cells with a glycosaminoglycan deposition of over 15 µg and the expression of chondrogenic markers. Full article

Peripheral nerve adhesion after surgical injury severely hinders functional nerve regeneration, leading to pain and neurological dysfunction. In this study, we developed a photocrosslinkable methacrylated gelatin (GelMA)-based hydrogel membrane that locally releases dexamethasone to simultaneously prevent adhesion and suppress inflammation. GelMA, synthesized by reacting gelatin with methacrylic anhydride, formed a stable crosslinked network, as confirmed by FT-IR spectroscopy and rheological analysis. Cytocompatibility assays showed that both GelMA and Dexa-GelMA hydrogels were non-cytotoxic to neuronal and fibroblast cell lines. In a Sprague-Dawley (SD) rat sciatic nerve injury model, implantation of the Dexa-GelMA hydrogel significantly reduced perineural adhesion and inflammation compared with the untreated control. Western blot analysis showed an approximately 80% reduction in ED-1 expression, indicating suppression of macrophage activation. Overall, the Dexa-GelMA hydrogel provides a biocompatible, multifunctional platform that integrates physical barrier function with anti-inflammatory drug delivery, showing strong potential for preventing postoperative nerve adhesion and modulating early inflammatory responses in a peripheral nerve injury model. Full article

Three-dimensional (3D) culture systems that recapitulate the tumor microenvironment are essential for studying cancer cell behavior, drug response, and cell–matrix interactions. Here, we present a detailed protocol for generating 3D spheroid cultures from murine breast cancer cells using methacrylated gelatin (GelMA)-based bioink and a CELLINK BioX bioprinter. This method enables precise deposition of spheroid-laden GelMA droplets into low-attachment plates, facilitating high-throughput and reproducible 3D culture formation. The protocol includes steps for spheroid formation, GelMA preparation, bioprinting, and post-printing analysis using a customized CellProfiler pipeline. The analysis pipeline takes advantage of the functionality of CellProfiler and ImageJ software (version 2.14.0) packages to create a versatile and accessible analysis tool. This approach provides a robust and adaptable platform for in vitro cancer research, including studies of metastasis, drug resistance, cancer cell lipid metabolism, and TME-associated hypoxia. Full article

Background: Chronic wounds, especially in diabetic patients, pose a significant clinical challenge due to current treatment limitations and an increasingly affected population. A major issue is the stalled inflammatory phase, which prevents proper healing. This study developed a novel co-delivery system to address the deficiency of growth factors and persistent inflammation in chronic wounds. Methods: Gelatin nanoparticles (NPs) were synthesized to carry curcumin, an anti-inflammatory compound. These curcumin-loaded NPs (NP/Curc) were then incorporated into gelatin methacrylate (GelMA) hydrogels to form a hierarchical delivery construct, nanoparticles encased within a hydrogel. These hydrogels were then cryogenically milled into microparticles (MPs) to carry human mesenchymal stem cells (hMSCs). The viability and growth of hMSCs on the surface of curcumin-loaded MPs were evaluated. The release of curcumin from various MP configurations was analyzed. The anti-inflammatory effects of the MPs were assessed by measuring pro-inflammatory cytokine expression in human monocyte THP-1 cells. Results: Curcumin directly loaded into hydrogels showed a rapid burst release within three days. In contrast, NP/Curc had a more sustained release profile. Curcumin incorporation did not adversely affect the cell-carrier functions of MPs. Conditioned media from hMSCs cultured on the plain MPs demonstrated anti-inflammatory effects in THP-1 cells. Low doses of curcumin released from the MPs also showed anti-inflammatory activity. The combination of hMSCs and curcumin exhibited an additive effect in reducing IL-8 expression by 4× in THP-1 cells. Conclusions: This study demonstrates the feasibility of co-delivering cells and curcumin without compromising the cell viability of hMSCs. Using gelatin nanoparticles as a carrier prolongs curcumin release, offering a sustained therapeutic effect. This strategy of hierarchical delivery of curcumin and co-delivery of cells represents a promising approach for treating chronic wounds by simultaneously providing growth factors and reducing inflammation. Full article

Gelatin methacryloyl (GelMA) hydrogels are widely used in tissue engineering because of their tunable mechanical and biological properties. However, many studies have arbitrarily selected key synthesis parameters, such as methacrylic anhydride (MA) concentration, (lithium phenyl-2 4 6-trimethyl-benzoyl phosphinate) LAP concentration, GelMA content, UV exposure time, and reaction duration, without clear justification. This study aimed to systematically optimize GelMA hydrogel fabrication and evaluate the mechanical and biological performances of the resulting hydrogels for craniofacial muscle tissue engineering. Hydrogels were synthesized following a standardized protocol, and the reaction progress was confirmed via proton nuclear magnetic resonance (¹H-NMR). The swelling ratio, degradation behavior, compressive strength, and metabolic activity (AlamarBlue assay using C2C12 myoblasts) were assessed. Statistical analysis was performed using independent t-tests and one-way ANOVA with Tukey’s post hoc test (p < 0.05). The results showed that small variations in MA concentration and reaction time significantly affected the hydrogel properties. Higher GelMA concentrations (10–20%) enhanced the mechanical strength but reduced the biological activity. LAP ≥ 0.5% and prolonged UV exposure lowered metabolic activity, whereas 0.1% LAP with 1–2 min of UV exposure provided an optimal balance. These findings provide a reproducible framework for GelMA fabrication and establish a foundation for developing tailored biomaterials for muscle tissue engineering. Full article

Hydrogels have attracted considerable attention as biomedical materials owing to their distinctive properties; however, improvements in mechanical strength, biodegradability, and biocompatibility remain essential for advanced clinical applications. This study developed a new dual-crosslinked hydrogel based on gelatin (Gel) and dextran (Dex) via sequential aldimine condensation and photopolymerization. Natural Gel and Dex were functionalized to synthesize methacrylated Gel (GelMA) and oxidized Dex (ODex), respectively. An imine-linked network was initially formed between GelMA and ODex via aldimine condensation, followed by a second crosslinked network generated through blue-light-induced free-radical polymerization of GelMA, yielding dual-crosslinked hydrogels (GMODs). ¹H NMR and FT–IR analyses confirmed the successful functionalization and formation of dual-crosslinked structure. The dual-crosslinked network enhanced the thermal stability and water-retaining capacity of the freeze-dried hydrogels (DGMODs) while reducing the surface wettability and equilibrium swelling ratio of GMODs. The maximum compressive strength (σₘ) increased with crosslinking density; GMOD−2, with moderate crosslinking density, remained intact under 85% compressive strain and achieved σₘ of 108.0 kPa. The degradation rate of GMODs was tunable by adjusting the crosslinking density, thereby modulating their drug-release behavior. GMOD−3, possessing the highest crosslinking density, exhibited effective drug-sustained release for up to five weeks. Biological evaluations, including cytotoxicity assays, live/dead cell staining, and hemolysis tests, verified excellent cytocompatibility (cell survival rate > 92%) and minimal hemolysis ratio (<5%). Furthermore, inhibition zone tests preliminarily revealed moderate antibacterial activity for GMOD−1. The GMOD hydrogels exhibited superior compressive robustness, adjustable biodegradability, and excellent biocompatibility, holding great potential for biomedical applications such as sustained drug-delivery system. Full article

Gelatin methacrylate (GelMA) microgels serve as promising bioscaffolds for tissue engineering and drug screening. However, conventional solid GelMA microgels often exhibit limited mass transfer efficiency and provide insufficient protection for embedded cells. In this study, we developed a droplet-based microfluidic platform to fabricate core–shell structured GelMA microgels. This system enabled precise control over microgel size and core-to-shell ratio by modulating flow rates. Encapsulation of A549 cells within these core–shell microgels preserved cellular viability and facilitated the formation of three-dimensional tumor spheroids. These outcomes confirmed both the protective function of the core–shell architecture during encapsulation and the overall biocompatibility of the microgels. The developed GelMA core–shell microgel system presents considerable applicability in research domains such as organoid modeling and high-throughput pharmacological screening. Full article

Regenerative endodontics seeks to restore the vascularized pulp–dentin complex following conventional root canal therapy, yet reliable neovascularization within the constrained root canal remains a key challenge. This study investigates the development of an injectable, dual-curing hydrogel based on methacrylated decellularized amniotic membrane (dAM-MA) and compares its performance to a conventional gelatin methacryloyl (GelMA). The dAM-MA platform was designed for biphasic release, incorporating both free vascular endothelial growth factor (VEGF) for an initial burst and matrix-metalloproteinase-cleavable VEGF conjugates for sustained delivery. The dAM-MA hydrogel achieved shape-fidelity via thermal gelation at 37 °C and possessed tunable stiffness (0.5–7.8 kPa) after visible-light irradiation. While showing high cytocompatibility comparable to GelMA (>125% hDPSC viability), the dAM-MA platform markedly outperformed the control in promoting endothelial tube formation (up to 800 µm total length; 42 branch points at 96 h). The biphasic VEGF release from dAM-MA matched physiological injury kinetics, driving both early chemotaxis and late vessel maturation. These results demonstrate that dAM-MA hydrogels combine native extracellular matrix complexity with practical, dual-curing injectability and programmable VEGF kinetics, offering a promising scaffold for minimally invasive pulp–dentin regeneration. Full article