Chemical Cross-linking Research Articles

Enlightenment the dynamic behavior of norbornene–modified ’click’ 4–arm polyethylene glycol hydrogel: Delving into framework properties and transport properties through molecular dynamics simulations

The thiol-norbornene cross-linked 4-arm Polyethylene Glycol (PEG) ’click’ hydrogel is a synthetic, sustainable, and bio-inspired polymer extensively used in biomedical applications. Experimental techniques are widely used to study this system, whereas all-atom molecular dynamics simulations, which offer insight into the dynamic behaviours of the system, are never used to study this system. Three models of thiol-norbornene cross-linked PEG ’click’ hydrogel and a base PEG hydrogel are crafted. It is immersed in water to study its structural and transport properties. Structural properties are analysed through root-mean-square deviation (RMSD), radial distribution function (RDF), hydrogen bonds (H-bond), and stress–strain behavior. The RMSD reveals that the norbornene component enhances hydrogel stability compared to the base model. The RDF illustrates interactions between oxygen in PEG chains and water. H-bond results underscore PEG’s strong H-bond acceptance. The norbornene-functionalized crosslinked PEG hydrogel displays maximum H-bonding. It demonstrates a superior swelling ratio attributed to freezing and non-freezing water effects, indicating high stability and potential suitability for applications. Mean square displacements (MSD) unveil the diffusion coefficients of the hydrogel. The base hydrogel model shows the diffusive behavior, and the diffusion coefficient is 1.97 × 10-10 m2/s. The base model has the highest MSD value compared to other systems. The thiol-norbornene crosslinked click hydrogel has the highest Young’s modulus, which signifies the stiffness of the material. Findings illuminate thiol-norbornene ’click’ PEG hydrogel behaviour, emphasising chemical cross-linking’s crucial role in advanced biomedical applications.

Comprehensive Review of Hydrogel Synthesis, Characterization, and Emerging Applications

Hydrogels play a crucial role due to their high-water content and 3D structure, which make them ideal for various applications in biomedicine, sensing, and beyond. They can be prepared from a variety of biomaterials, polymers, and their combinations, allowing for versatility in properties and applications. Hydrogels include natural types derived from collagen, gelatin, alginate, and hyaluronic acid, as well as synthetic types based on polyethylene glycol (PEG), polyvinyl alcohol (PVA), and polyacrylamide (PAAm). Each type possesses distinct properties, such as mechanical strength, biodegradability, and biocompatibility, which can be tailored for applications such as wound healing, contact lenses, 3D bioprinting, and tissue engineering. The high-water content of hydrogels mimics natural tissue environments, promoting cell growth and allowing nutrient and waste exchange, which supports the development of functional tissues. They serve as scaffolds in tissue engineering applications, including wound healing, cartilage and bone regeneration, vascular tissue engineering, and organ-on-a-chip systems. Additionally, hydrogels can encapsulate and deliver therapeutic agents, such as growth factors or drugs, to specific target sites in the body. Hydrogels can be prepared through three primary methods: physical crosslinking, which relies on non-covalent interactions such as physical entanglements or hydrogen bonding; chemical crosslinking, which forms covalent bonds between polymer chains to create a stable structure; and irradiation-based crosslinking, where UV irradiation induces rapid hydrogel formation. The choice of crosslinking method depends on the desired properties and applications of the hydrogel. By providing a biomimetic environment, hydrogels facilitate cell growth and differentiation, support tissue formation, and aid in the regeneration of damaged or diseased tissues while delivering therapeutic agents. This review focuses on the critical advancements in processing routes for hydrogel development, summarizing the characterization and application of hydrogels. It also details key applications, including wound healing and cartilage and bone regeneration, as well as the challenges and future perspectives in the field.

Novel rubber-steel adhesive based on resole phenol formaldehyde/unsaturated polyester/soybean oil polyol blends with high thermal stability performance

One of the main challenges in rubber-metal adhesive is improving the adhesion strength performance with high thermal stability. A novel rubber-steel adhesives based on resole phenol formaldehyde/unsaturated polyester/soybean oil polyol blends were fabricated to tackle this challenge. SEM investigated the morphology of the fabricated blends, while the curing reaction and the components’ interactions were evaluated using FT-IR and XRD. The heat resistance and curing properties were studied by TGA and DSC. The adhesion properties for rubber-metal adhesive specimens were tested at room temperature. The impact of soybean oil polyol modifier addition was investigated on adhesion performance. The curing conditions (touch dry, full curing, and shelf life) and hardness were investigated. It is obvious that polyol improves the heat resistance of the prepared films and enhances their adhesion behavior. The fabricated adhesive exhibits good adhesion and thermal stability due to the integration of chemical cross-linking in the matrix. It can adhere extensively to substrate surfaces via intermolecular forces with small physical movements. Controlling the curing time and delaying the shelf life could be possible for samples that take a long time to cure completely. The designed fabricated adhesive appeared to desired properties of satisfactory rubber-metal adhesion and good thermal stability.

A novel bio-aerogel based on agroforestry waste chestnut shell for enhanced oil-water separation performance

Bio-based aerogels have attracted much attention due to their biodegradability and excellent oil-water separation properties. However, the preparation of inexpensive green aerogels with high separation efficiency is still a great challenge. In this paper, low-density, high-adsorption capacity and superhydrophobic chestnut shell-based bio-aerogels were prepared by chemical cross-linking and chemical vapor deposition using agricultural and forestry waste chestnut shells as the precursor of aerogels to achieve high efficiency of oil-water separation and to achieve the goal of “treating waste with waste”. The covalent cross-linking of chestnut shell cellulose and cross-linking agent to form silicone-containing functional groups improved the pore structure, hydrophobicity and mechanical properties of chestnut shell cellulose, and under the action of capillary force, the oil was retained in the pores of the bio-aerogels, which achieved the selective adsorption of oil and organic solvents in the oil-water mixture, with a separation efficiency of more than 98%. After 10 cycles, the bio-aerogel still has good reusability. This eco-friendly and low-cost aerogel provides a practical method for resource conversion and recycling, as well as a green and innovative way for the treatment of oily wastewater.

Novel high-strength, recyclable, microbial-resistant, and freeze-thaw dual topological network hydrogel cooling media

The demand for multifunctional hydrogels, offering high mechanical strength, efficient cooling, and antimicrobial properties, is growing in food preservation. Here, a dual-network (DN) hydrogel PM@Cur, which includes curcumin, is fabricated through chemical crosslinking and hydrogen bonding interactions. The resulting hydrogels can withstand more than five freeze-thaw cycles at −80 °C, and resist brittleness after liquid nitrogen treatment. PM@Cur also exhibits surface hydrophobicity (contact angle >90°) for both water and organic solvents. These properties meet the mechanical, anti-fouling, and recyclable demands for hydrogel coolants. The antimicrobial assays in vitro confirmed that the inclusion of curcumin provided the PM@Cur with photodynamic antimicrobial capacity. Finally, the prepared PM@Cur hydrogel ice cubes have been confirmed to exhibit better anti-melting properties than traditional ice cubes, thus enabling the preservation of strawberries and shrimp. This study presents an innovative solution for producing advanced functional integrated hydrogels, offering a promising and safer option for food coolants.\\.

Enhanced high-temperature energy storage performance in all-organic dielectric films through synergistic crosslinking of chemical and physical interaction

Advanced electronic devices and energy systems urgently require high-temperature polymer dielectrics that can offer both high discharge energy density and energy storage efficiency. However, the capacitive properties of most polymers sharply deteriorate at elevated temperatures, due to the significant rise in leakage current density and energy loss. Herein, a new design approach is adopted to fabricate high-temperature polyetherimide (PEI) dielectrics with chemical and physical cooperative crosslinking networks, the dual-crosslinked PEI dielectrics are prepared through amine crosslinking agent and the electrostatic interaction of oppositely charged phenyl groups between triptycene (TE) and PEI chain segments. Benefiting from the increased crosslinking sites, the dual-crosslinked PEI films achieve the simultaneously enhancement in Tg, modulus and bandgap compared to un-crosslinked and single-crosslinked polymers. Meanwhile, the PEI with dual-crosslinked network displays higher chain packing density, effectively reducing the mean motion pathways of charge carriers and the conduction loss inside polymer dielectric. Consequently, the dual-crosslinked PEI containing 0.25 wt% TE delivers an outstanding discharge energy density of 2.69 J/cm3 and retains excellent cyclability after 100,000 charge–discharge cycles at 200 ℃. Additionally, finite element analysis and molecular dynamics simulation further confirm that less Joule heat and tighter chain structure are formed in the dual-crosslinked polymer dielectric. This research offers a novel methodology to prepare high-performance polymer dielectrics for high-temperature applications.

High salt-resistant and robust MXene@oleylamine/PET composite nonwoven for efficient and long-term solar desalination

2D transition metal carbides/nitrides/carbonitrides (MXenes) have received extensive attention in solar seawater desalination due to their hydrophilicity, 100 % photothermal conversion efficiency, and efficient light-trapping by enhancing localized surface plasmon resonance (LSPR). Nevertheless, the easily oxidizable characteristics of MXenes, along with salt accumulation and structural weakness impede their practical application in solar-driven interfacial evaporators. Herein, a hydrophobic MXene@oleylamine/polyethylene terephthalate (MXene@OAm/PET) nonwoven with long-term operational stability is fabricated via firmly chemical cross-linking between oleylamine (OAm) modified MXene (MXene@OAm) and NH2-PEG-COOH treated PET nonwoven (PEG-PET). The MXene@OAm endows excellent oxidation resistance and hydrophobicity. The prepared MXene@OAm/PET nonwoven which exhibits broad-spectrum solar absorption and high efficiency, can achieve an average evaporation rate in 3.5 wt% NaCl solution at 1.26 kg·m−2·h−1 and no seeable salt deposition during 15 irradiation cycles for 8 h a day indicates its superior salt resistance and long-term stability. Most importantly, after being soaked in 3.5 wt% NaCl solution for 40 days, the evaporation rate of MXene@OAm/PET nonwoven still remains stable at around 1.22 kg·m−2·h−1, indicating the significant potential of this prepared nonwoven for long-term seawater desalination and its suitability for industrial applications. Even in industrial wastewater, the evaporation rate can reach 1.27 kg·m−2·h−1. This work demonstrates a successful strategy for achieving high efficiency, stability, and superior salt resistance, which can be potentially utilized in seawater desalination and wastewater treatment.

Preparation of PAAS/GL/GO anti-freezing conductive hydrogels based on chemical cross-linking networks and their application in wearable sensors

Preparation of PAAS/GL/GO anti-freezing conductive hydrogels based on chemical cross-linking networks and their application in wearable sensors

Water as a Structural Marker in Gelatin Hydrogels with Different Cross-Linking Nature

We have studied the molecular properties of water in physically and chemically cross-linked gelatin hydrogels by FTIR-spectroscopy, NMR relaxation, and diffusivity and broadband dielectric spectroscopy, which are sensitive to dynamical properties of water, being a structural marker of polymer network. All experiments demonstrated definite reinforcement of the hydrogel net structure and an increase in the amount of hydrate water. FTIR experiments have shown that the chemical cross-linking of gelatin molecules initiates an increase in the collagen-like triple helices “strength”, as a result of infused restriction on protein molecular mobility. The “strengthening” of protein chains hinders the mobility of protein fragments, introducing complex modifications into the structural properties of water which are remained practically unchanged up to up to 30–40 °C.

Emerging Frontiers in In Situ Forming Hydrogels for Enhanced Hemostasis and Accelerated Wound Healing.

With a surge in the number of accidents and chronic wounds worldwide, there is a growing need for advanced hemostatic and wound care solutions. In this regard, in situ forming hydrogels have emerged as a revolutionary biomaterial due to their inherent properties, which include biocompatibility, biodegradability, porosity, and extracellular matrix (ECM)-like mechanical strength, that render them ideal for biomedical applications. This review demonstrates the advancements of in situ forming hydrogels, tracing their evolution from injectable to more sophisticated forms, such as sprayable and 3-D printed hydrogels. These hydrogels are designed to modulate the pathophysiology of wounds, enhancing hemostasis and facilitating wound repair. The review presents different methodologies for in situ forming hydrogel synthesis, spanning a spectrum of physical and chemical cross-linking techniques. Furthermore, it showcases the adaptability of hydrogels to the dynamic requirements of wound healing processes. Through a detailed discussion, this article sheds light on the multifunctional capabilities of these hydrogels such as their antibacterial, anti-inflammatory, and antioxidant properties. This review aims to inform and inspire continued advancement in the field, ultimately contributing to the development of sophisticated wound care solutions that meet the complexity of clinical needs.

Targeted Analysis of Mitochondrial Protein Conformations and Interactions by Endogenous ROS-Triggered Cross-Linker Release.

The study of in situ conformations and interactions of mitochondrial proteins plays a crucial role in understanding their biological functions. Current chemical cross-linking mass spectrometry (CX-MS) has difficulty in achieving in-depth analysis of mitochondrial proteins for cells without genetic modification. Herein, this work develops the reactive oxygen species (ROS)-responsive cross-linker delivery nanoparticles (R-CDNP) targeting mitochondria. R-CDNP contains mitochondria-targeting module triphenylphosphine, ROS-responsive module thioketal, loading module poly(lactic-co-glycolic acid) (PLGA), and polyethylene glycol (PEG), and cross-linker module disuccinimidyl suberate (DSS). After targeting mitochondria, ROS-triggered cross-linker release improves the cross-linking coverage of mitochondria in situ. In total, this work identifies 2103 cross-linked sites of 572 mitochondrial proteins in HepG2 cells. 1718 intra-links reveal dynamic conformations involving chaperones with ATP-dependent conformation cycles, and 385 inter-links reveal dynamic interactions involving OXPHOS complexes and 27 pairs of possible potential interactions. These results signify that R-CDNP can achieve dynamic conformation and interaction analysis of mitochondrial proteins in living cells, thereby contributing to a better understanding of their biological functions.

Optical characterization of molecular interaction strength in protein condensates.

Biomolecular condensates have been identified as a ubiquitous means of intracellular organization, exhibiting very diverse material properties. However, techniques to characterize these material properties and their underlying molecular interactions are scarce. Here, we introduce two optical techniques - Brillouin microscopy and quantitative phase imaging (QPI) - to address this scarcity. We establish Brillouin shift and linewidth as measures for average molecular interaction and dissipation strength, respectively, and we used QPI to obtain the protein concentration within the condensates. We monitored the response of condensates formed by FUS and by the low-complexity domain of hnRNPA1 (A1-LCD) to altering temperature and ion concentration. Conditions favoring phase separation increased Brillouin shift, linewidth, and protein concentration. In comparison to solidification by chemical crosslinking, the ion-dependent aging of FUS condensates had a small effect on the molecular interaction strength inside. Finally, we investigated how sequence variations of A1-LCD, that change the driving force for phase separation, alter the physical properties of the respective condensates. Our results provide a new experimental perspective on the material properties of protein condensates. Robust and quantitative experimental approaches such as the presented ones will be crucial for understanding how the physical properties of biological condensates determine their function and dysfunction.

Synergistic Dual-Cross-Linking Gelation: Exploring the Impact of Metal-Ligand Complexation on Ionogel Performance.

Owing to the growing interest in wearable ionotronics, the demand for ionogels with outstanding mechanical and electrochemical characteristics has increased dramatically. Nevertheless, it remains challenging to simultaneously enhance the mechanical robustness and conductivity of ionogels because of their trade-off relationship. In this work, we propose physically/chemically dual-cross-linked ionogels designed to improve the mechanical strength without reducing ionic conductivity by introducing metal-ligand complexation only within the physically cross-linked domains. In particular, the impact of metal-ligand complexation, a crucial parameter in this strategy, on ionogel performance is systematically examined using various metal ions. The mechanical resilience and thermal stability of ionogels are effectively enhanced with Co3+ having the highest coordination number, which can be explained by the highest metal-ligand complexation (i.e., chemical cross-linking) density. Additionally, there is no degradation in ionic conductivity when compared to the pristine ionogel because these complexations occur within physically cross-linking domains that are irrelevant to the ion conductive channels. The dual-cross-linked ionogels are successfully applied to alternating-current electroluminescent displays (ACEDs). Moreover, a versatile mixed-emitter strategy is suggested to improve practicality, enabling the realization of frequency-controlled multicolor ACEDs.

High Ion-Conductive Hydrogel: Soft, Elastic, with Wide Humidity Tolerance and Long-Term Stability.

Ion-conductive hydrogels have received great attention due to their significant potential in flexible electronics. However, achieving hydrogels that simultaneously possess high ionic conductivity and stability under varying humidity conditions remains a challenge, limiting their practical applications. Herein, we propose a thermally controlled chemical cross-linking strategy to prepare an elastic and conductive hydrogel (ECH) of poly(vinyl alcohol) (PVA) with high content of H2SO4. The covalent cross-links formed effectively tackle the instability issue in high humidity of physically cross-linked PVA/H2SO4 hydrogels with high ionic conductivity, which were previously developed via the polymer-in-salt strategy. We systematically investigated the reaction conditions and clarified the methods to optimize the hydroxyl dehydration of PVA, resulting in excellent mechanical properties and ion conductivity simultaneously. The ECH demonstrates impressive ionic conductivity (up to 392 ± 49 mS cm-1) and elasticity (over 80% resilience upon stretching and compression after being equilibrated at various humidity levels for 24 days). Thanks to the excellent water retention of the high H2SO4 content, the ECH maintains an ionic conductivity exceeding 210 mS cm-1 for over 420 days at 50% relative humidity (RH) and retains over 100 mS cm-1 even after 3 days under extremely dry conditions (7% RH). These remarkable properties make the ECH an ideal candidate for applications requiring reliable ionic conductivity in diverse environmental conditions. Additionally, we demonstrated that the ECH can function as a stretchable Joule heater with high conformability for heating up objects with curved surfaces. The heating rate could reach a fast rate of ∼12 °C s-1 even when a human-safe alternating current voltage is below 36 V, attributed to the high ionic conductivity. We believe that the high performance and ease of fabrication make our hydrogels a promising candidate for use as electrolytes in flexible energy storage devices, electrolyte gates in electrochemical transistors, and artificial skin, which often face long-term stability challenges under varying humidity conditions.

Highly conductive and sensitive alginate hydrogel strain sensors fabricated using near-field electrohydrodynamic direct-writing process

Hydrogel flexible sensors have attracted considerable attention because of their wearability, biocompatibility, and precision signal transmission capability. However, the hydrogel strain sensors fabricated by conventional printing or hand-injection methods have difficulty balancing their mechanical strength and sensing characteristics, limiting the application of hydrogel strain sensors. Herein, polyvinyl alcohol and polyacrylamide were loosely crosslinked with sodium alginate through chemical cross-linking. Subsequently, MXene nanosheets were introduced for doping, the crosslinked hydrogel conductive network was constructed, and the hydrogel strain sensors were fabricated using the electrohydrodynamic (EHD) printing method. The ions in the EHD-printed hydrogel undergo directional movement under an externally enhanced electric field, causing the formation of more uniform and dense porous conductive networks inside the hydrogel, and high electrical conductivity (0.49 S m−1) is obtained. These hydrogel strain sensors have excellent mechanical properties (tensile strength: 0.17 MPa at 787 % strain), high sensitivity (gauge factor: 1.54 at 0–100 % strain), and low detection limits (1 % strain). Furthermore, demonstrations of real-time Morse code tapping information transmission, handwriting recognition during writing, and human physiological behavior monitoring demonstrations using the fabricated sensors indicate that the EHD-printed hydrogel strain sensor method has significant potential for wearable devices and human-computer interaction applications.

Suppression of Zinc Dendrite Growth by Enhanced Polyacrylamide Gel Electrolytes in Zinc-Ion Battery.

Aqueous zinc-ion batteries have become a promising energy storage battery due to high theoretical specific capacity, abundant zinc resources and low cost. However, zinc dendrite growth and hydrogen evolution reaction limit their application. This study aims to improve the cycling performance and stability of aqueous zinc-ion batteries by improving the gel electrolyte. Polyacrylamide (PAM) is selected as the base material of the gel electrolyte, which has good stability and safety, but the water retention capacity, Zn2+ migration number, and ionic conductivity of PAM are low, which affects the long-term stability of the battery. In response to these problems, we optimized PAM by chemical cross-linking method, and formed an enhanced PAM gel by adding disodium citrate dihydrate (SC). Experimental results show that the introduction of an appropriate amount of SC in the enhanced PAM gel electrolyte can significantly improve its electrochemical performance. The zinc-ion symmetric battery achieved a stable cycle of more than 2100 hours at a current density of 0.5 mA cm-2, which is mainly attributed to the inhibitory effect of the enhanced PAM gel on zinc dendrite growth and hydrogen evolution reaction. This study provides a new direction for the development and application of flexible zinc-ion batteries.

Polyethyleneimine assisted zeolitic imidazolate frameworks foam embed silver to enhance the uranium recovery from seawater

The powder structure, poor surface wettability and biofouling significantly limited the application potential of ZIFs (zeolitic imidazolate frameworks) in uranium extraction from seawater. Herein, a superhydrophilic polyethyleneimine assisted zeolitic imidazolate frameworks foam embed silver (CPEZ8A) was successfully prepared by simple chemical cross-linking and in-situ growth methods to explore the effects of hydrophilic matrix and silver antimicrobial agent on the uranium adsorption properties of ZIFs materials. The mechanical property and water contact angle test of CPEZ8A foam were performed to confirm its higher compression stress (with 1.314 MPa) and surface superhydrophilic. Moreover, CPEZ8A foam displayed an excellent resistance to biological attachment after 7 days in algae solution. Importantly, CPEZ8A showed the maximum U (VI) uptake capacity (775.19 mg/g) with 4.37 times of pure ZIF-8 at nearly seawater pH and retained relative high U-uptake amount during the broad pH range (4.0–9.0). Ion competition experiments were also investigated to verify the CPEZ8A foam excellent selectivity (Kd = 15,072.1 mL/g). Notably, the removal rate of CPEZ8A foam reach 81.31 % in natural seawater and remain nearly 80 % in simulated contaminated seawater. Therefore, this work provides an effective strategy to develop highly efficient ZIFs adsorbents for uranium capture.

Effective multi-biocatalyst system with reusable NADH for transformation of glycerol to value-added dihydroxyacetone

Glycerol-based biorefinery can be a highly profitable process by producing highly value-added products such as dihydroxyacetone via combined catalytic strategies. Here, two-enzyme system is adopted for the transformation of glycerol into highly valuable dihydroxyacetone as well as cofactor regeneration at the same time. Glycerol dehydrogenase (GDH) and alcohol dehydrogenase (ADH) are co-immobilized within magnetically separable and spherical mesocellular silica foam (Mag-S-MCF), to prepare NER-(GDH/ADH). In details, GDH and ADH are adsorbed into the mesopores of Mag-S-MCF, and further crosslinked within the mesopores of Mag-S-MCF. The resulting nanoscale enzyme reactors (NER) of crosslinked GDH and ADH molecules within the bottle-neck structured mesopores can effectively prevent larger sized crosslinked enzyme aggregates from being leached out of smaller mesopores, due to the bottle-neck mesopore structure of Mag-S-MCF, as well as stabilize the activity of GDH and ADH upon chemical crosslinking, effectively preventing the denaturation of enzyme molecules. More importantly, the proximity of GDH and ADH molecules within mesopores of NER improves the efficiency of cofactor-mediated dual-enzymatic reactions by relieving mass-transfer limitations and improving cofactor recycling in an effective way, expediting both glycerol oxidation and dihydroxyacetone generation at the same time. As a result, the DHA concentration of NER-(GDH/ADH) and the simple mixture of NER-GDH and NER-ADH were 410 μM and 336 μM, respectively. To the best of our knowledge, this report is the first demonstration of stabilized nanoscale multi-enzyme reactor system, equipped with efficient cofactor regeneration within confined mesopores, for efficient glycerol transformation to high-valued dihydroxyacetone.Graphical

A self-adjuvanted VLPs-based Covid-19 vaccine proven versatile, safe, and highly protective

Vaccination has played a critical role in mitigating COVID-19. Despite the availability of licensed vaccines, there remains a pressing need for improved vaccine platforms that provide high protection, safety, and versatility, while also reducing vaccine costs. In response to these challenges, our aim is to create a self-adjuvanted vaccine against SARS-CoV-2, utilizing Virus-Like Particles (VLPs) as the foundation. To achieve this, we produced bacteriophage (Qβ) VLPs in a prokaryotic system and purified them using a rapid and cost-effective strategy involving organic solvents. This method aims to solubilize lipids and components of the cell membrane to eliminate endotoxins present in bacterial samples. For vaccine formulation, Receptor Binding Domain (RBD) antigens were conjugated using chemical crosslinkers, a process compatible with Good Manufacturing Practice (GMP) standards. Transmission Electron Microscopy (TEM) confirmed the expected folding and spatial configuration of the QβVLPs vaccine. Additionally, vaccine formulation assessment involved SDS-PAGE stained with Coomassie Brilliant Blue, Western blotting, and stereomicroscopic experiments. In vitro and in vivo evaluations of the vaccine formulation were conducted to assess its capacity to induce a protective immune response without causing side effects. Vaccine doses of 20 µg and 50 µg stimulated the production of neutralizing antibodies. In in vivo testing, the group of animals vaccinated with 50 µg of vaccine formulation provided complete protection against virus infection, maintaining stable body weight without showing signs of disease. In conclusion, the QβVLPs-RBD vaccine has proven to be effective and safe, eliminating the necessity for supplementary adjuvants and offering a financially feasible approach. Moreover, this vaccine platform demonstrates flexibility in targeting Variants of Concern (VOCs) via established conjugation protocols with VLPs.

Advancements in Hydrogels for Corneal Healing and Tissue Engineering.

Hydrogels have garnered significant attention for their versatile applications across various fields, including biomedical engineering. This review delves into the fundamentals of hydrogels, exploring their definition, properties, and classification. Hydrogels, as three-dimensional networks of crosslinked polymers, possess tunable properties such as biocompatibility, mechanical strength, and hydrophilicity, making them ideal for medical applications. Uniquely, this article offers original insights into the application of hydrogels specifically for corneal tissue engineering, bridging a gap in current research. The review further examines the anatomical and functional complexities of the cornea, highlighting the challenges associated with corneal pathologies and the current reliance on donor corneas for transplantation. Considering the global shortage of donor corneas, this review discusses the potential of hydrogel-based materials in corneal tissue engineering. Emphasis is placed on the synthesis processes, including physical and chemical crosslinking, and the integration of bioactive molecules. Stimuli-responsive hydrogels, which react to environmental triggers, are identified as promising tools for drug delivery and tissue repair. Additionally, clinical applications of hydrogels in corneal pathologies are explored, showcasing their efficacy in various trials. Finally, the review addresses the challenges of regulatory approval and the need for further research to fully realize the potential of hydrogels in corneal tissue engineering, offering a promising outlook for future developments in this field.