Multifaceted Hydrogel Scaffolds: Bridging the Gap between Biomedical Needs and Environmental Sustainability

Advanced 3D scaffolds for corneal stroma regeneration: a preclinical progress

Corneal stromal defects represent a significant global cause of blindness, necessitating innovative therapeutic strategies to address the limitations of conventional treatments, such as corneal transplantation. Tissue engineering, a cornerstone of regenerative medicine, offers a transformative approach by leveraging biomaterial-based solutions to restore damaged tissues. Among these, three-dimensional (3D) scaffolds fabricated using advanced techniques like 3D printing have emerged as a promising platform for corneal regeneration. These scaffolds replicate the native extracellular matrix (ECM) architecture, providing a biomimetic microenvironment that supports cell proliferation, differentiation, and tissue integration. This review highlights recent advances in the design and fabrication of 3D scaffolds for corneal stroma engineering (CSE), emphasizing the critical interplay between scaffold architecture, mechanical properties, and bioactive signaling in directing cellular behavior and tissue regeneration. Likewise, we emphasize the diverse range of biomaterials utilized in scaffold fabrication, highlighting their influence on cellular interactions and tissue reconstruction. By elucidating the complex relationship between scaffold design and biologics, this review aims to illuminate the evolution of next-generation strategies for engineering functional corneal tissue. Eventually, this review will provide a comprehensive synthesis of the current state-of-the-art in 3D scaffold-based corneal tissue engineering (CTE), offering insights that could advance progress toward effective vision restoration therapies.

Emerging Trends and Future Prospects of Peptide-Based Hydrogels: Revolutionizing Food Technology Applications

Peptide-based hydrogels (PHs) are versatile materials with considerable potential in food technology. Advances in synthesis techniques, such as self-assembly, click chemistry, enzymatic cross-linking, and co-assembly with polymers, have improved their production efficiency and scalability. Derived from natural amino acids, PHs are biocompatible, biodegradable, and responsive to environmental factors like pH and temperature. In food technology, encapsulation and controlled release of bioactive compounds enhance nutrient stability, flavor preservation, and bioavailability. PHs serve as texture modifiers, improve product consistency, and possess antimicrobial properties for food preservation by inhibiting spoilage and pathogens. Their biodegradability supports eco-friendly practices and sustainable packaging, including edible films and coatings that extend shelf life. Adjustable properties such as ionic strength make PHs adaptable to specific needs. PHs also show potential in developing advanced food equipment, including 3D printers and encapsulation systems, promoting efficiency and sustainability. This review emphasizes that PHs offer innovative, sustainable solutions to enhance food functionality, quality, and safety, with broad applications in food processing and preservation.

ROS-Activated Nanohydrogel Scaffolds with Multi-Factors Controlled Release for Targeted Dual-Lineage Repair of Osteochondral Defects

Achieving self-healing for osteochondral defects caused by trauma, aging, or disease remains a significant challenge in clinical practice. It is an effective therapeutic strategy to construct gradient-biomimetic biomaterials that replicate the hierarchical structure and complex microenvironment of osteochondral tissues for dual-lineage regeneration of both cartilage and subchondral bone. Herein, ROS-activated nanohydrogels composite bilayer scaffolds with multi-factors controlled release are rationally designed using the combination of 3D printing and gelatin placeholder methods. The resulting nanohydrogel scaffolds exhibit micro-nano interconnected porous bilayer structure and soft-hard complex mechanical strength for facilitating 3D culture of BMSCs in vitro. More importantly, multi-stage continuous responses of anti-inflammation, chondrogenesis and osteogenesis, are effectively induced via the sequential release of multi-factors, including diclofenac sodium (DS), kartogenin (KGN) and bone morphogenetic protein 2 (BMP-2), from ROS-activated nanohydrogel scaffolds, thereby improved dual-lineage regeneration of cartilage and subchondral bone tissue in the osteochondral defect model of SD rats. These findings suggest that ROS-activated nanohydrogel scaffolds with such specific soft-hard bilayer structure and sequential delivery of functional factors, provides a promising strategy in dual-lineage regeneration of osteochondral defects.

Biomaterial-based chitosan nanohydrogel films: combination of Bistorta officinalis and Ca-doped carbon dots for improved blood clotting

BACKGROUND

Bleeding and traumatic injuries are still a major issue necessitating the development of advanced hemostatic materials that are economical, biocompatible, and effective. Chitosan's (CS) haemostatic and biocompatible properties make it a promising wound-healing material, however, effective cross-linking is essential for appropriate physiochemical properties. In this study, calcium-doped carbon dots (CDs) produced from coriander leaves were used as cross-linking agents to improve the functional performance and structural integrity of nanohydrogel films. Furthermore, extract of the medicinal plant Bistorta officinalis (BEX), a traditional medicinal plant with strong hemostatic and antibacterial qualities, was incorporated into the hydrogel matrix.

RESULTS

Analysis and characterization of the synthesized CDs thoroughly confirmed that they have monodispersed spherical shape, negative zeta potential, and active functional groups which effectively cross-linked the chitosan matrix and increased the mechanical strength and stability of the film. Cytotoxicity and antibacterial results of the final films showed the desired cytocompatibility against Human skin fibroblast (HFF-1 cells) with over 80% viability at the highest concentration and effective antibacterial activity against gram-positive and gram-negative bacteria (further improved by cross-linking with CDs and incorporating BEX), respectively. The incorporation of BEX and CDs in hydrogel films significantly enhanced the film's blood-clotting ability with negligible hemolysis due to blood clotting index and hemolysis tests.

CONCLUSIONS

The findings of this study highlight the potential of biomaterial-based nano hydrogel film, composed of CS cross-linked with CDs and containing BEX, as a promising wound dressing with outstanding biocompatibility, minimal cytotoxicity, enhanced hemostatic efficacy, and strong antibacterial properties.

Effects of hydrogel stiffness and viscoelasticity on organoid culture: a comprehensive review

As an emerging technology, organoids are promising new tools for basic and translational research in disease. Currently, the culture of organoids relies mainly on a type of unknown composition scaffold, namely Matrigel, which may pose problems in studying the effect of mechanical properties on organoids. Hydrogels, a new material with adjustable mechanical properties, can adapt to current studies. In this review, we summarized the synthesis of recent advance in developing definite hydrogel scaffolds for organoid culture and identified the critical parameters for regulating mechanical properties. In addition, classified by different mechanical properties like stiffness and viscoelasticity, we concluded the effect of mechanical properties on the development of organoids and tumor organoids. We hope this review enhances the understanding of the development of organoids by hydrogels and provides more practical approaches to investigating them.

Acid-Triggered Dual-Functional Hydrogel Platform for Enhanced Bone Regeneration

Stem cell implantation holds promise for enhancing bone repair, but risks of pathogen transmission and malignant cell transformation should not be ignored. Compared to stem cell implantation, recruitment of endogenous stem cells to injured sites is more critical for in situ bone regeneration. In this study, based on the acidic microenvironment of bone injury, an HG-AA1:1-SDF-1α composite hydrogel with a dual-control intelligent switch function is developed by incorporating stromal cell-derived factor (SDF-1α), arginine carbon dots (Arg-CDs), and calcium ions (Ca2+) into the oxidized hyaluronic acid/gelatin methacryloyl (HG) hydrogel. The acidic microenvironment triggers the first switch (Schiff base bond is broken between HG-AA1:1 and SDF-1α) of HG-AA1:1-SDF-1α composite hydrogel to continuously release SDF-1α. Compared to the neutral (pH 7.4) media, the cumulative release of SDF-1α in acidic (pH 5.5) media is ≈2.5 times higher, which enhances the migration and recruitment of endogenous mesenchymal stem cells (MSCs). The recruited MSCs immediately initiate the second switch and metabolize Arg-CDs into the bioactive nitric oxide (NO) in the presence of Ca2+, activating NO/cyclic guanosine monophosphate (cGMP) signaling pathway to promote angiogenesis. Therefore, the engineered HG-AA1:1-SDF-1α composite hydrogel shows promising potential to achieve "coupling osteogenesis and angiogenesis" for bone regeneration.

Injured Cardiac Tissue-Targeted Delivery of TGFβ1 siRNA by FAP Aptamer-Functionalized Extracellular Vesicles Promotes Cardiac Repair

Purpose

Small-interfering RNA (siRNA) therapy holds significant potential for treating cardiac injury; however, its clinical application is constrained by poor blood stability and insufficient cellular uptake. Extracellular vesicles (EVs) have emerged as an effective delivery system for siRNA in vivo; but their lack of specific cell or tissue-targeting ability remains a major challenge. Thus, we aimed to develop an EV-based delivery system capable of targeted delivery of therapeutic siRNA to injured cardiac tissue for cardiac repair.

Methods

To identify fibroblast activation protein (FAP) as a potential target for delivery to injured cardiac tissue, we analyzed cardiac tissues from patients with heart failure and angiotensin II (Ang II)-treated mice. Injured cardiac tissue-targeting EVs were developed by embedding a cholesterol-conjugated FAP aptamer, which specifically targets FAP, onto human serum-derived EVs (hEV).

Results

Our findings revealed that FAP is upregulated after cardiac injury, highlighting its potential as a target for siRNA delivery to injured cardiac tissues. We successfully developed FAP aptamer-functionalized hEV (hEV@FAP) and confirmed their typical EV characteristics, including morphology, size distribution, zeta potential, and marker protein expression. In addition, hEV@FAP demonstrated high targeting selectivity to FAP-positive regions both in vitro and in vivo. To treat cardiac injury, hEV@FAP were loaded with TGFβ1 siRNA (siTGFβ1), identified as a molecular target for cardiac repair. In Ang II-treated mice, intravenous administration of hEV@FAP-siTGFβ1 effectively reduced Ang II-induced TGFβ1 expression in cardiac tissues, attributed to the protective and targeting capabilities of hEV@FAP. Consequently, hEV@FAP-siTGFβ1 significantly improved cardiac function, reduced myocardial fibrosis, and decreased cardiomyocyte cross-sectional area (P < 0.05) without inducing systemic toxicity.

Conclusion

hEV@FAP represents a novel approach for targeted delivery of therapeutic siRNA to injured cardiac tissues, providing a promising nanomedicine for cardiac repair.

Tissue Engineering 3D-Printed Scaffold Using Allograft/Alginate/Gelatin Hydrogels Coated With Platelet-Rich Fibrin or Adipose Stromal Vascular Fraction Induces Osteogenesis In Vitro

Incorporating autologous patient-derived products has become imperative to enhance the continually improving outcomes in bone tissue engineering. With this objective in mind, this study aimed to evaluate the osteogenic potential of 3D-printed allograft-alginate-gelatin scaffolds coated with stromal vascular fraction (SVF) and platelet-rich fibrin (PRF). The primary goal was to develop a tissue-engineered construct capable of facilitating efficient bone regeneration through the utilization of biomaterials with advantageous properties and patient-derived products. To achieve this goal, 3D-printed gelatin, allograft, and alginate scaffolds were utilized, along with stem cells derived from the buccal fat pad and human-derived components (PRF, SVF). Cells were seeded onto scaffolds, both with and without SVF/PRF, and subjected to comprehensive assessments including adhesion, proliferation, differentiation (gene expression and protein secretion levels), penetration, and gene expression analysis over 14 days. The data was reported as mean ± standard deviation (SD). Two-way or one-way analysis of variance (ANOVA) was performed, followed by a Tukey post hoc test for multiple comparisons. Statistical significance was determined as a p value below 0.05. The scaffolds demonstrated structural integrity, and the addition of PRF coatings significantly enhanced cellular adhesion, proliferation, and differentiation compared to other groups. Gene expression analysis showed increased expression of osteogenic and angiogenic markers in the PRF-coated scaffolds. These findings highlight the promising role of PRF-coated scaffolds in promoting osteogenesis and facilitating bone tissue regeneration. This study emphasizes the development of patient-specific tissue-engineered constructs as a valuable approach for effective bone regeneration.

Curcumin-assisted Preparation of α-Fe2O3@TiO2 Nanocomposites for Antibacterial and Photocatalytic Activity

BACKGROUND

Harmful microorganisms like pathogens significantly impact human health. Meanwhile, industrial growth causes pollution and water contamination by releasing untreated hazardous waste. Effective treatment of these microorganisms and contaminants is essential, and nanocomposites may be a promising solution. The present attempt demonstrates the green synthesis of α-Fe2O3@TiO2 nanocomposites (FTNCs) for the effective treatment of pathogens and organic contaminants.

METHODS

The FTNCs have been synthesized through a green approach utilizing curcumin extract. Curcumin (Turmeric) extract (TEx) was prepared by washing, drying, and crushing 5 g of turmeric, then boiling it in 100 mL distilled water at 70°C for 1 hour. Metal salts (Fe3+/Ti4+, 2:1) were added to 100 mL of TEx under continuous stirring at 70°C for 24 h. The solution was rinsed and dried at 80°C overnight and heated at 300°C for 3 h to remove impurities.

RESULTS

Synthesized FTNCs have been tested for the potent antibacterial activity against both Gram-positive (Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Salmonella Abony, Pseudomonas sp.). Observations discovered noteworthy inhibition of both Gram-positive and Gramnegative bacteria by FTNCs. Furthermore, the FTNCs system shows the energy band gap of ~2.6 eV which may suppress electron recombination, thereby enhancing photocatalysis. The photo-degradation is examined against Evans blue (EB) and Congo red (CR) dyes under UV and visible light (125 W) irradiation. The remarkable photocatalytic degradation efficiency (DE) for CR reached ~67.4% in 60 min.

CONCLUSION

A simple green approach has been demonstrated for the synthesis of the FTNCs using curcumin-mediated reduction. As prepared FTNCs have been evaluated for potent antibacterial activity against both Gram-positive (Staphylococcus aureus, Bacillus subtilis, Enterococcus faecalis) and Gram-negative bacteria (Escherichia coli, Salmonella Abony, Pseudomonas sp.). The results show that the highest zone of inhibition diameter values have been obtained for 5 mg/mL concertation of FTNCs of ~14, 22, 18, 21, and 20 and 29 mm for E. coli, S. abony, S. aureus, B. subtilis, E. faecalis, and Pseudomonas sp., respectively. Additionally, FTNCs demonstrate remarkable photocatalytic degradation efficiency against EB and CR dyes under UV (125 W) irradiation, achieving 56, 67% degradation within 60 min, respectively. The findings indicate that FTNCs show long-term antimicrobial effectiveness and potential for water treatment through photocatalysis. This examination highlights recent advancements in intellectual property rights (IPR) and patent strategies, shedding light on how patents influence eco-friendly synthesis and the development of multifunctional, high-performance nanocomposites.

High-Efficiency Broad-Spectrum Antibacterial Activity of Chitosan/Zinc Ion/Polyoxometalate Composite Films for Water Treatment

The development of multifunctional films with rapidly killing microorganisms and adsorbing residual antibiotics in wastewater remains a challenging endeavor. In this work, the chitosan/zinc ion/polyoxometalate (CS/Zn2+/POM) multifunctional films were prepared by the freeze-drying method using chitosan, ZnO, and POM. Notably, the CS/Zn2+/POM films exhibited excellent bactericidal properties against Gram-positive/negative bacterial strains including Staphylococcus aureus (S. aureus, 99.80%), Escherichia coli (E. coli, 99.82%), and drug-resistant E. coli bacterial strains (kanamycin-resistant E. coli, 87.76% and ampicillin-resistant E. coli, 99.71%). This may be due to the chelation of Zn2+ with CS disrupting the cell membrane and bringing POM into direct contact with bacteria, leading to bacterial death. In addition, the CS/Zn2+/POM films showed good adsorption performance to a tetracycline (TC) solution (adsorption rate 75.2%). Further studies showed that the main process of tetracycline removal by CS/Zn2+/POM films was controlled by a physical adsorption. This POM-based film material has an important potential for the synthesis of broad-spectrum antimicrobial materials for the removal of residual antibiotics from water pollutants such as tetracycline.

Applications of piezoelectric biomaterials in dental treatments: A review of recent advancements and future prospects

Piezoelectric biomaterials have attracted considerable attention in dental medicine due to their unique ability to convert mechanical force into electricity and catalyze reactions. These materials demonstrate biocompatibility, high bioactivity, and stability, making them suitable for applications such as tissue regeneration, caries prevention, and periodontal disease treatment. Despite their significant potential, the clinical application of these materials in treating oral diseases remains limited, facing numerous challenges in clinical translation. Therefore, further research and data are crucial to advance their application in dentistry. The review emphasizes the transformative impact of multifunctional piezoelectric biomaterials on enhancing dental therapies and outlines future directions for their integration into oral healthcare practices.

Novel Supramolecular Hydrogel for Infected Diabetic Foot Ulcer Treatment

Multifunctional responsive hydrogels hold significant promise for diabetic foot ulcer (DFU) treatment, though their complex design and manufacturing present challenges. This study introduces a novel supramolecular guanosine-phenylboronic-chlorogenic acid (GBC) hydrogel developed using a dynamic covalent strategy. The hydrogel forms through guanosine quadruplex assembly in the presence of potassium ions and chlorogenic acid (CA) linkage via dynamic borate bonds. GBC hydrogels exhibit pH and glucose responsiveness, releasing more chlorogenic acid under acidic and high glucose conditions due to borate bond dissociation and G-quadruplex (G4) hydrogel disintegration. Experimental results indicate that GBC hydrogels exhibit good self-healing, shear-thinning, injectability, and swelling properties. Both in vitro and in vivo studies demonstrate the GBC hydrogel's good biocompatibility, ability to eliminate bacteria and reactive oxygen species (ROS), facilitate macrophage polarization from the M1 phenotype to the M2 phenotype (decreasing CD86 expression and increasing CD206 expression), exhibit anti-inflammatory effects (reducing TNF-α expression and increasing IL-10 expression), and promote angiogenesis (increasing VEGF, CD31, and α-SMA expression). Thus, GBC hydrogels accelerate DFU healing and enhance tissue remodeling and collagen deposition. This work provides a new approach to developing responsive hydrogels to expedite DFU healing.

A Novel Hydrogel Sponge for Three-Dimensional Cell Culture

BACKGROUND/OBJECTIVES

Three-dimensional (3D) cell culture technologies allow us to overcome the constraints of two-dimensional methods in different fields like biochemistry and cell biology and in pharmaceutical in vitro tests. In this study, a novel 3D hydrogel sponge scaffold, composed of a crosslinked polyacrylic acid forming a porous matrix, has been developed and characterized.

METHODS

The scaffold was obtained via an innovative procedure involving thermal treatment followed by a salt-leaching step on a matrix-containing polymer along with a gas-forming agent. Based on experimental design for mixtures, a series of formulations were prepared to study the effect of the three components (polyacrylic acid, NaHCO3 and NaCl) on the scaffold mechanical properties, density, swelling behavior and morphological changes. Physical appearance, surface morphology, porosity, molecular diffusion, transparency, biocompatibility and cytocompatibility were also evaluated.

RESULTS

The hydrogel scaffolds obtained show high porosity and good optical transparency and mechanical resistance. The scaffolds were successfully employed to culture several cell lines for more than 20 days.

CONCLUSIONS

The developed scaffolds could be an important tool, as such or with a specific coating, to obtain a more predictive cellular response to evaluate drugs in preclinical studies or for testing chemical compounds, biocides and cosmetics, thus reducing animal testing.