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Background: Oxidative stress is a major contributor to granulosa cell dysfunction and follicular atresia, with excessive reactive oxygen species (ROS) impairing mitochondrial activity and cell survival. Hydrogels based on gelatin methacryloyl (GelMA) are biocompatible and easily photocrosslinked, but they lack intrinsic antioxidant function. Methods: A GelMA–tannic acid (TA) hydrogel was synthesized by visible light curing in the presence of TA. Structural features were confirmed by FT-IR and ¹H NMR. Photorheology was used to determine gelation kinetics, and scanning electron microscopy assessed morphology. Antioxidant performance was evaluated by DPPH, ABTS, FRAP, and H₂O₂ assays. The protective effect on human granulosa-like KGN cells under H₂O₂ stress was examined by CCK-8 viability, DCFH-DA ROS detection, JC-1 mitochondrial membrane potential, and Live/Dead staining. Results: GelMA–TA exhibited a rapid gelation time of 8.5 s and a plateau modulus of 1.8 kPa, higher than the 1.5 kPa modulus of GelMA alone. In antioxidant assays, GelMA–TA showed significant radical scavenging activity with DPPH (86.1%), ABTS (91.4%), and FRAP (1.15 mmol Fe²⁺ equivalent), as well as nearly complete H₂O₂ removal (94.8%). In KGN cells, GelMA–TA reduced intracellular ROS by 60%, restored mitochondrial membrane potential (Δψm) to 0.9 (compared to 0.5 for H₂O₂ treatment), and improved cell viability by 30%. Conclusion: These findings demonstrate that GelMA–TA forms a fast-curing, antioxidant hydrogel capable of maintaining a low-ROS microenvironment and protecting granulosa cells, offering a promising platform for ovarian tissue engineering and related regenerative applications.

Background: Reactive oxygen species (ROS)–induced oxidative stress contributes to neuronal injury during ischemic conditions, creating a need for delivery systems that can release therapeutic molecules in response to oxidative cues. Incorporating thioketal linkages into polymeric materials provides a feasible strategy to construct ROS-degradable carriers. Methods: In this study, a triblock copolymer poly(ε-caprolactone)–thioketal–poly(ε-caprolactone) (PCL–PTK–PCL) was synthesized via ring-opening polymerization using thioketal diol as the initiator. The polymer self-assembled into nanocarriers capable of encapsulating nerve growth factor (NGF). The structural characteristics were analyzed by FTIR and TEM, while the degradation and release behaviors were evaluated under various H₂O₂ concentrations. Cytocompatibility and neuronal viability were assessed using PC12 cells. Results: The PCL–PTK–PCL nanocarriers exhibited uniform spherical morphology with an average size of ~100 nm. The presence of thioketal bonds conferred clear ROS sensitivity, as evidenced by H₂O₂-triggered swelling and accelerated NGF release. The carriers remained stable under non-oxidative conditions and showed good cytocompatibility, maintaining high neuronal cell viability after incubation. Conclusion: The synthesized PCL–PTK–PCL nanocarriers achieved ROS-triggered degradation and controlled NGF release while exhibiting minimal cytotoxicity. These findings confirm their suitability as a basic oxidation-responsive platform for further exploration in oxidative stress–related neuronal studies.

Background: The liver tumor microenvironment is characterized by elevated reactive oxygen species (ROS), high glutathione (GSH) levels, and acidic pH, which limits the selectivity and efficacy of conventional chemotherapy. Microenvironment-responsive drug delivery systems offer a promising strategy to address these challenges. Methods: A redox-responsive thioketal-crosslinked gelatin hydrogel (TK-Gel) was prepared via dynamic covalent crosslinking and used to encapsulate doxorubicin (DOX). The rheological properties, swelling and degradation behaviors, redox responsiveness, and microenvironment-dependent drug release were systematically evaluated. In vitro antitumor performance was assessed using HepG2 liver cancer cells. Results: The TK-Gel hydrogel formed a stable and highly hydrated network under physiological conditions, while exhibiting accelerated degradation and enhanced DOX release under tumor-mimicking environments with elevated ROS and GSH. Cellular studies demonstrated good biocompatibility of the blank hydrogel and significantly enhanced cytotoxicity of DOX@TK-Gel under redox-activated conditions, accompanied by partial intracellular ROS consumption. Conclusions: Thioketal-crosslinked gelatin hydrogels enable tumor-selective drug release and redox modulation, providing a promising platform for liver cancer therapy.

Background: A suitable biomaterial scaffold is essential for building in vitro ovarian models. This study developed a GelMA/HAMA (GH) hydrogel to support granulosa cell culture and to construct a simplified coculture system for granulosa cell–endothelial cell interaction. Methods: GH hydrogel was characterized by rheology, tensile testing, scanning electron microscopy, swelling, degradation, and extract-based cytocompatibility. KGN granulosa cells were encapsulated in GH hydrogel, and an aging-like model was induced with H₂O₂. A Transwell system and conditioned-medium experiments were used to evaluate endothelial cell responses. Results: GH hydrogel showed light-triggered gelation, predominantly elastic behavior, higher tensile performance than GelMA, lower swelling, and slower degradation, with acceptable cytocompatibility at the tested range. In KGN-laden hydrogels, H₂O₂ treatment increased ROS and p16 expression while decreasing E2 secretion and StAR expression. Conditioned medium from aging granulosa cells increased ROS and VCAM-1 and reduced HUVEC viability. Conclusion: GH hydrogel provides a controllable matrix for granulosa cell culture and a useful in vitro platform for studying aging-related granulosa cell–endothelial cell crosstalk.

Background: The fabrication of vascular-mimetic hydrogel scaffolds with precise luminal geometry, suitable elasticity, and good cytocompatibility remains a major challenge in tissue engineering. Digital light processing (DLP) printing offers high resolution and rapid fabrication, but over-curing and limited structural fidelity in hollow constructs still restrict its application in vascular-like scaffold fabrication. Methods: In this study, GelMA-based tubular scaffolds with Y-shaped and curved vascular geometries were fabricated by DLP printing. To improve printing precision, 0.02% (w/v) tartrazine was introduced as a light-absorbing agent to regulate light penetration and curing depth during the photopolymerization process. The printed scaffolds were characterized by optical imaging and scanning electron microscopy, while their mechanical properties were evaluated through tensile and compression tests. Cytocompatibility was assessed using CCK-8 assay, Live/Dead staining, and quantitative cell survival analysis. Results: The incorporation of tartrazine effectively reduced excessive light penetration during printing, enabling the formation of continuous tubular structures with improved lumen definition and structural integrity. The DLP-printed GelMA scaffolds showed high geometric fidelity, with smooth and stable inner channels of approximately 1 mm in diameter. Mechanical testing demonstrated a nonlinear J-shaped tensile response and strain-stiffening behavior under compression, indicating favorable elasticity and resistance to deformation. In vitro biological evaluation further showed high cell viability, with CCK-8 results remaining above the control level and Live/Dead staining confirming a predominance of viable cells on the scaffold surface. Conclusion: The incorporation of a small amount of photoabsorber enabled high-resolution DLP printing of vascular-like GelMA scaffolds with excellent mechanical flexibility and biocompatibility. These constructs hold strong potential as perfusable, elastic hydrogel platforms for microvascular regeneration, endothelialization studies, and organ-on-chip applications.

Background: Thermosensitive hydrogels have been widely investigated for localized drug delivery; however, their in vitro physicochemical stability, degradation behavior, and cell-level anti-inflammatory performance require systematic evaluation before further translational studies. In particular, prostate epithelial inflammation remains an underexplored application scenario for such delivery platforms. Methods: In this study, a PLGA–PEG–PLGA thermosensitive hydrogel was evaluated as a sustained delivery system for dexamethasone. The copolymer was characterized by GPC, FTIR, and ¹H NMR. Sol–gel transition behavior and viscoelastic properties were assessed using micro-DSC and rheological analysis. The microstructure of the drug-loaded hydrogel was examined by SEM. Degradation behavior was investigated under physiological (PBS, 37°C) and accelerated alkaline conditions. Cytocompatibility and anti-inflammatory effects were evaluated in RWPE-1 prostate epithelial cells. Results: SEM revealed an interconnected porous network structure in the drug-loaded hydrogel. Degradation studies showed high structural stability in PBS with minimal mass loss over 14 days, while rapid degradation occurred under alkaline conditions, confirming hydrolytic degradability. The hydrogel enabled sustained dexamethasone release and maintained good cytocompatibility. Notably, dexamethasone-loaded hydrogels significantly reduced IL-6 and IL-8 secretion, whereas blank hydrogels showed no intrinsic anti-inflammatory effect. Conclusion: This work provides a comprehensive in vitro evaluation of a thermosensitive PLGA–PEG–PLGA hydrogel for sustained dexamethasone delivery at the cellular level. The results clarify the relationship between hydrogel microstructure, degradation behavior, and diffusion-dominated drug release, establishing a solid foundation for future in vivo investigations.

The consideration of additive manufacturing as a production method leads to a new approach with other elements of manufacturing technology systems. In this research article, a robot-assisted manufacturing method is considered in order to increase the efficiency and accuracy of the 3D printing process. There are two possibilities of 3D printing when a robot arm is used: a conventional one (plane-to-plane printing) and a non-planar/continuous one when a 3-dimensional trajectory is used. The aim of the research is to establish the differences between the mechanical properties and precision of 3D printed parts using these two methods of 3D printing. This paper presents a methodology used in control software for both the robotic arm and the extruder, converting 3D models into executable robotic instructions, and performing accurate hardware calibration. The material selected for the experiments was ONYX, which is a composite material that includes carbon fiber, which has better properties with respect to metal, namely, low weight, better mechanical strength, rigid parts under repeated loads, better adaptability for customization, and suitability for on-demand production. These properties are required in the automotive and aerospace industries. In the experiments carried out, several parameters were taken into account, such as UV radiation, humidity, nozzle diameter, and temperature (printing speed is constant). The samples were subjected to tensile tests, and the results obtained are discussed in the paper.

This study aimed to comprehensively compare the flexural strength, degree of conversion (Dc), and repair flexural strength of three bulk-fill resin composites: SDR Plus, Beautifil Bulk Flow, and EverX Posterior under simulated clinical conditions. Specimens of each composite (n = 10) were fabricated and polymerized and their Dc was assessed using ATR-FTIR spectroscopy after 24 h. Bar-shaped specimens underwent thermocycling and were tested for flexural strength using a three-point bending test. Following the initial fracture, specimens were either repaired with the original composite or with Filtek™ Supreme Flowable Restorative and then retested. Failure modes were analyzed under stereomicroscopy. Data were statistically analyzed using one-way and two-way ANOVA with significance set at p < 0.05. EverX Posterior showed significantly higher flexural strength (153.48 MPa) but lower Dc (59.6%) compared to SDR Plus and Beautifil Bulk Flow, which presented higher Dc values (68.33% and 66.27%, respectively). Repair flexural strength varied depending on the composite and repair material, with fiber-reinforced EverX Posterior significantly benefiting from flowable composite repair. Adhesive failure was predominant except for some cohesive failures in EverX Posterior repaired with flowable resin. Fiber-reinforced composites demonstrated superior mechanical strength suitable for stress-bearing applications, while flowable bulk-fill composites achieved higher polymerization efficiency. Repair using flowable composites may enhance repair flexural strength, particularly for fiber-reinforced bulk-fill materials. However, as this was an in vitro study without long-term aging, fatigue, or bonding durability evaluation, the findings should be interpreted with caution and may not directly reflect long-term clinical performance.

Background: Antiphospholipid syndrome (APS) is a major cause of pregnancy morbidity, characterized by antiphospholipid antibody–induced platelet activation and placental thrombosis. Integrin αIIbβ3 is a key mediator of platelet aggregation in this pathological process. Methods: We developed PEGDA-based hydrogels functionalized with acrylated RGD peptides to competitively bind αIIbβ3 and inhibit platelet aggregation. The effects of hydrogel and αIIbβ3 antibody treatments were evaluated in vitro using integrin-binding assays, turbidity-based platelet aggregation and clotting assays, ELISA for cytokine release, and transwell migration of trophoblasts. Results: RGD-modified hydrogels showed dose-dependent binding to αIIbβ3. Both hydrogel and antibody treatments significantly reduced antiphospholipid antibodies (aPL)-induced platelet aggregation, delayed fibrin clot formation, and suppressed IL-6 and TNF-α release from trophoblasts. Cell migration assays confirmed that these interventions preserved trophoblast motility impaired by aPL exposure. Conclusion: Targeting integrin αIIbβ3 with RGD-functionalized biomaterials or neutralizing antibodies effectively attenuated aPL-mediated thromboinflammation. This approach represents a promising localized intervention strategy to prevent APS-related pregnancy complications.

Recycling polymeric waste is a key component of the circular economy, aiming to reduce environmental impact and resource consumption. However, polymeric blends obtained from mixed recycled plastics often exhibit variable mechanical properties due to differences in composition and compatibility among constituent polymers. This study investigates the flexural behavior of a recycled polymeric blend to assess its suitability for applications requiring moderate bending loads. Samples consisting of approximately 70% polyethylene (LDPE and HDPE), 20% polypropylene, and minor fractions of ABS, PET, and PA6/6 were fabricated by a two-stage extrusion–molding process without washing or compatibilization. Three-point bending tests were conducted in accordance with SR ISO 178:2019 using an Instron 5982 universal testing machine at five crosshead speeds (10–1000 mm/min). Mechanical parameters—including maximum force, flexural stress, Young’s modulus, strain, and absorbed energy—were determined. Differential scanning calorimetry (DSC) was employed to confirm blend composition and homogeneity. The recycled blend exhibited flexural stress values between 14 and 19 MPa and a flexural modulus ranging from 0.61 to 0.83 GPa, with minimal dependence on test rate. The absorbed energy at 50 mm displacement varied between 14 J and 18.5 J, and no cracking or brittle fracture occurred at any test rate. The material displayed good elastic recovery after the test and a narrow standard deviation across all mechanical parameters, indicating reproducibility and homogeneity. The results demonstrate that the recycled polymeric blend possesses stable and repeatable mechanical performance under bending, comparable to conventional HDPE/LDPE or PP-based materials. Its low rate sensitivity and energy absorption capacity support its potential use in non-structural or moderately loaded components (up to ~12 MPa), providing a viable, eco-friendly alternative to virgin polymers or wood-based materials in various applications.