The relationship between volunteering and cognitive performance in older adults: A systematic review.

OBJECTIVES: This systematic review aims to examine the relationship between cognition and volunteering in older adults, with a specific focus on domain-specific outcomes. METHODS: In April 2023, a comprehensive search was conducted across multiple electronic databases including PubMed, Google Scholar, ScienceDirect, Web of Science, and Scopus. The inclusion criteria for the study were limited to longitudinal studies or randomized controlled trials (RCTs). The quality and risk of bias of the included articles were assessed using the Newcastle-Ottawa Scale and Consolidated Standards of Reporting Trials (CONSORT). RESULTS: Out of 3575 articles retrieved, 17 studies were eligible for inclusion in this review. The majority of these studies were conducted in high-income countries. Of the 17 studies reviewed, 16 found a positive association between volunteering and cognitive benefits. CONCLUSION: The analysis of seventeen studies meeting the predefined inclusion criteria suggests a potential positive correlation between volunteering and cognitive function among older adults. Some demographic factors such as gender and education level were observed to have an influence on this relationship. It was found that older adults who engage in volunteering may exhibit better episodic memory, working memory, and verbal fluency compared to non-volunteers. However, due to limitations in the existing research and variations across studies, further investigation is needed to establish definitive conclusions.

Insights into mustard gas keratopathy: Characterizing corneal layer-specific changes in mice exposed to nitrogen mustard.

Exposure to mustard agents, such as sulfur mustard (SM) and nitrogen mustard (NM), often results in ocular surface damage. This can lead to the emergence of various corneal disorders that are collectively referred to as mustard gas keratopathy (MGK). In this study, we aimed to develop a mouse model of MGK by using ocular NM exposure, and describe the subsequent structural changes analyzed across the different layers of the cornea. A 3 µL solution of 0.25 mg/mL NM was applied to the center of the cornea via a 2-mm filter paper for 5 min. Mice were evaluated prior to and after exposure on days 1 and 3, and weekly for 4 weeks using slit lamp examination with fluorescein staining. Anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM) tracked changes in the epithelium, stroma, and endothelium of the cornea. Histologic evaluation and immunostaining were used to examine corneal cross-sections collected at the completion of follow-up. A biphasic ocular injury was observed in mice exposed to NM, most prominent in the corneal epithelium and anterior stroma. Following exposure, mice experienced central corneal epithelial erosions and thinning, accompanied by a decreased number of nerve branches in the subbasal plexus and increased activated keratocytes in the stroma. The epithelium was recovered by day 3, followed by exacerbated punctuate erosions alongside persistent stromal edema that arose and continued onward to four weeks post-exposure. The endothelial cell density was reduced on the first day after NM exposure, which persisted until the end of follow-up, along with increased polymegethism and pleomorphism. Microstructural changes in the central cornea at this time included dysmorphic basal epithelial cells, and in the limbal cornea included decreased cellular layers and p63+ area, along with increased DNA oxidization. We present a mouse model of MGK using NM that successfully replicates ocular injury caused by SM in humans who have been exposed to mustard gas. Our research suggests DNA oxidation contributes to the long-term effects of nitrogen mustard on limbal stem cells.

Insights into mustard gas keratopathy- characterizing corneal layer-specific changes in mice exposed to nitrogen mustard.

Exposure to mustard agents, such as sulfur mustard (SM) and nitrogen mustard (NM), often results in ocular surface damage. This can lead to the emergence of various corneal disorders that are collectively referred to as mustard gas keratopathy (MGK). In this study, we aimed to develop a mouse model of MGK by using ocular NM exposure, and describe the subsequent structural changes analyzed across the different layers of the cornea. A 3 µL solution of 0.25 mg/mL or 5 mg/mL NM was applied to the center of the cornea via a 2-mm filter paper for 5 min. Mice were evaluated prior to and after exposure on days 1, 3, 7, 14, and 28 for 4 weeks using slit lamp examination with fluorescein staining. Anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM) tracked changes in the epithelium, stroma, and endothelium of the cornea. Histologic evaluation was used to examine corneal cross-sections collected at the completion of follow-up. Following exposure, mice experienced central corneal epithelial erosion and thinning, accompanied by a decreased number of nerve branches in the subbasal plexus and increased activated keratocytes in the stroma in both dosages. The epithelium was recovered by day 3 in the low dose group, followed by exacerbated punctuate erosions alongside persistent corneal edema that arose and continued onward to four weeks post-exposure. The high dose group showed persistent epitheliopathy throughout the study. The endothelial cell density was reduced, more prominent in the high dose group, early after NM exposure, which persisted until the end of follow-up, along with increased polymegethism and pleomorphism. Microstructural changes in the central cornea at 4 weeks post-exposure included dysmorphic basal epithelial cells and reduced epithelial thickness, and in the limbal cornea included decreased cellular layers. We present a mouse model of MGK using NM that successfully replicates ocular injury caused by SM in humans who have been exposed to mustard gas.

Association of intergenerational relationship and supports with cognitive performance in older adults: A systematic review.

OBJECTIVE: As individuals age, cognitive decline can significantly impact their quality of life. This systematic review aims to investigate the potential association between parent-child relationships among older adults in Eastern Asian countries and their cognitive performance. METHODS: For this research, a systematic search was conducted on several electronic databases including PubMed, Scopus, Web of Science, ScienceDirect, and Google Scholar search engine, up to March 2023. RESULTS: Out of 418 articles, 6 were eligible for inclusion in the study. The findings suggest that intergenerational relationships, particularly emotional support and two-way financial communications, are associated with maintaining cognitive health in older adults. CONCLUSIONS: Intergenerational relationships affect cognitive health in older adults, with implications for healthcare, social welfare, and the economy. Further research is required to investigate the effects of children's visits on cognitive health and explore the complexities of intergenerational relationships on cognitive health in aging populations.

Potential small-molecule drugs as available weapons to fight novel coronavirus (2019-nCoV): A review.

Since the new coronavirus known as 2019-nCoV (severe acute respiratory syndrome coronavirus 2, SARS-CoV-2) has widely spread in Wuhan, China, with severe pneumonia, scientists and physicians have made remarkable efforts to use various options such as monoclonal antibodies, peptides, vaccines, small-molecule drugs and interferon therapies to control, prevent or treatment infections of 2019-nCoV. However, no vaccine or drug has yet been confirmed to completely treat 2019-nCoV. In this review, we focus on the use of potential available small-molecule drug candidates for treating infections caused by 2019-nCoV.

Chemical Constituent, Antimicrobial Activity, and Synergistic Effect of the Stem, Leaf, and Flower Essential Oil of the Artemisia fragrans Willd. from Khoy.

Artemisia fragrans is commonly used as a folk medicine as antispasmodic, anti-pyretic, anti-inflammatory, and abortifacient agents. The villagers use its pungent odor to repel rodents, mites, and pests, as well as its essential oil and smoke after burning to treat lung infections after uprooting the plant. Herein, we extracted the essential oils (EOs) of different parts of the plant and analyzed their chemical compositions and antibacterial activities. The chemical analysis led to the identification of 73, 59, and 57 compounds in the EOs of the stem, leaf, and flower, respectively. All of the EOs exhibited antibacterial activities against both G+ and G- bacteria. The EOs of the leaf and flower were more effective against tested bacteria, except B. anthracis and P. aeruginosa, compared to that of the stem. The binary combination of the EOs (stem and flower) or (stem and leaf) showed a synergistic effect. Statistical analysis indicated EOs of leaf and flower are more potent than that of the stem. These findings suggest the application of leaf and flower of the plant, which not only can prevent its uprooting but also ensure better therapeutic function.

Achillea filipendulina Lam.: Chemical Constituents and Antimicrobial Activities of Essential Oil of Stem, Leaf, and Flower.

In this study, we extracted the essential oils of the stem, leaf, and flower of Achillea filipendulina, analyzed them, and studied their antibacterial properties. Of 16, 53, and 35 compounds identified in the stem, leaf, and flowers, respectively, only five are present in all three segments of the plant. The essential oil of the stem was mainly composed of neryl acetate, spathulenol, carvacrol, santolina alcohol, and trans-caryophyllene oxide. However, the main identified components of leaf were 1,8-cineole, camphor, ascaridole, trans-isoascaridole, and piperitone oxide and the main components of the flower oil were ascaridole, trans-isoascaridole, 1,8-cineole, p-cymene, and camphor. The extracted oil from different segments demonstrated varying antibacterial properties against both Gram-positive and Gram-negative bacteria, demonstrated by disk, minimum inhibitory concentration, and minimum bactericidal concentration methods. These suggest that the application of all segments of aerial parts of A. filipendulina may have a better therapeutic effect in fighting pathogenic systems.

Effect of time-restricted eating and intermittent fasting on cognitive function and mental health in older adults: A systematic review.

Objective: Emerging evidence suggests that dietary interventions hold promise for promoting cognitive function and mental well-being in aging populations. This systematic review aimed to examine the potential relationship between Time-Restricted Eating (TRE) and Intermittent Fasting (IFA) with cognitive function and mental health in older adults. Methods: A thorough exploration was undertaken on electronic databases such as PubMed, Scopus, Web of Science, Science Direct, and Google Scholar, up to October 2023, following PRISMA standards. The evaluation of the quality and potential bias in the incorporated articles involved the use of the Newcastle-Ottawa Scale and Consolidated Standards of Reporting Trials (CONSORT). Results: From a total of 539 articles initially identified, eight studies met the eligibility criteria for inclusion in this review. Out of these eight studies, six focused on cognitive function, and 2 focused on mental health. The reviewed articles encompassed a wide range of population sizes, with the number of older adults studied varying from 10 to 1357, reflecting a diverse cohort of individuals. Conclusions.The findings suggest that TRE and IFA may have a positive impact on cognitive function and mental health in this population. However, additional research is needed to fully comprehend this relationship. Therefore, future research should specifically examine factors such as the duration and timing of the eating window in TRE, as well as the physical condition of older adults, to provide a more nuanced understanding of the cognitive and mental health benefits of TRE and IFA in older adults.

The association between intergenerational relationships and depression among older adults: A comprehensive systematic literature review.

OBJECTIVE: This systematic review aims to comprehensively examine the relationship between intergenerational relationships and depression among older adults in Eastern Asian countries. METHODS: For this research, a systematic search was conducted on several electronic databases including PubMed, Scopus, Web of Science, ScienceDirect, and Google Scholar search engine up until June 2023. RESULTS: Out of 953 articles initially identified, 33 met the inclusion criteria. Emotional support and financial support emerged as crucial factors that can significantly reduce depressive symptoms among older individuals. However, there are diverse and sometimes contradictory results regarding the impact of intergenerational instrumental support on depression in older adults. CONCLUSION: Promoting positive intergenerational relationships and enhancing support systems can greatly benefit the mental health of older adults by addressing depression within this population. This review enhances our understanding of the complex relationship between intergenerational relationships and depression among older adults. The diverse findings on intergenerational instrumental support and depression in older adults suggest the need for further research to clarify this relationship and its nuances. This research may have practical implications for policies and interventions aimed at improving the mental well-being of older adults in Eastern Asian countries.

Application of biomaterials and nanotechnology in corneal tissue engineering.

Corneal diseases are among the most common causes of blindness worldwide. Regardless of the etiology, corneal opacity- or globe integrity-threatening conditions may necessitate corneal replacement procedures. Several procedure types are currently available to address these issues, based on the complexity and extent of injury. Corneal allograft or keratoplasty is considered to be first-line treatment in many cases. However, a significant proportion of the world's population are reported to have no access to this option due to limitations in donor preparation. Thus, providing an appropriate, safe, and efficient synthetic implant (e.g., artificial cornea) may revolutionize this field. Nanotechnology, with its potential applications, has garnered a lot of recent attention in this area, however, there is seemingly a long way to go. This narrative review provides a brief overview of the therapeutic interventions for corneal pathologies, followed by a summary of current biomaterials used in corneal regeneration and a discussion of the nanotechnologies that can aid in the production of superior implants.

Characterization of Octa-aminopropyl polyhedral oligomeric silsesquioxanes (OA-POSS) nanoparticles and their effect on sweet basil (Ocimum basilicum L.) response to salinity stress.

Salt stress is of the most detrimental abiotic stress factors on either crop or non-crop species. Of the strategies employed to boost the performance of the plants against harmful impacts of salt stress; application of novel nano-engineered particles have recently gained great attention as a promising tool. Octa-aminopropyl polyhedral oligomeric silsesquioxanes nanoparticles (OA-POSS NPs) were synthesized and then a foliar-application of OA-POSS NPs were carried out on sweet basil plants subjected to the salt stress. In that context, interactive effects of OA-POSS NPs (25, 50 and 100 mg L-1) and salinity stress (50 and 100 mM NaCl) were assayed by estimating a series of agronomic, physiological, biochemical and analytical parameters. OA-POSS NPs decreased the harmful effects of salinity by increasing photosynthetic pigment content, adjusting chlorophyll fluorescence, and triggering non-enzymatic (phenolic content) and enzymatic antioxidant components. The findings suggested that 25 mg L-1 OA-POSS NPs is the optimum concentration for sweet basil grown under salt stress. Considering the essential oil profile, estragole was the predominant compound with a percentage higher than 50% depending on the treatment. In comparison to the control group, 50 mM NaCl did not significantly affect estragole content, whilst 100 mM NaCl caused a substantial increase in estragole content. Regarding OA-POSS NPs treatments, increments by 16.8%, 11.8% and 17.5% were observed following application with 25, 50 and 100 mg L-1, respectively. Taken together, the current study provides evidence that POSS NPs can be employed as novel, 'green' growth promoting agents in combating salt stress in sweet basil.

Electrospun-Reinforced Suturable Biodegradable Artificial Cornea.

Despite rigorous investigations, the hydrogels currently available to replace damaged tissues, such as the cornea, cannot fulfill mechanical and structural requirements and, more importantly, cannot be sutured into host tissues due to the lack of hierarchical structures to dissipate exerted stress. In this report, solution electrospinning of polycaprolactone (PCL), protein-based hydrogel perfusion, and layer-by-layer stacking are used to generate a hydrogel-microfiber composite with varying PCL fiber diameters and hydrogel concentrations. Integrating PCL microfibers into the hydrogel synergistically improves the mechanical properties and suturability of the construct up to 10-fold and 50-fold, respectively, compared to the hydrogel and microfiber scaffolds alone, approaching those of the corneal tissue. Human corneal cells cultured on composites are viable and can spread, proliferate, and retain phenotypic characteristics. Moreover, corneal stromal cells migrate into the scaffold, degrade it, and regenerate the extracellular matrix. The current hydrogel reinforcing system paves the way for producing suturable and, therefore, transplantable tissue constructs with desired mechanical properties.

Antiviral Polymers: A Review.

Polymers, due to their high molecular weight, tunable architecture, functionality, and buffering effect for endosomal escape, possess unique properties as a carrier or prophylactic agent in preventing pandemic outbreak of new viruses. Polymers are used as a carrier to reduce the minimum required dose, bioavailability, and therapeutic effectiveness of antiviral agents. Polymers are also used as multifunctional nanomaterials to, directly or indirectly, inhibit viral infections. Multifunctional polymers can interact directly with envelope glycoproteins on the viral surface to block fusion and entry of the virus in the host cell. Polymers can indirectly mobilize the immune system by activating macrophages and natural killer cells against the invading virus. This review covers natural and synthetic polymers that possess antiviral activity, their mechanism of action, and the effect of material properties like chemical composition, molecular weight, functional groups, and charge density on antiviral activity. Natural polymers like carrageenan, chitosan, fucoidan, and phosphorothioate oligonucleotides, and synthetic polymers like dendrimers and sialylated polymers are reviewed. This review discusses the steps in the viral replication cycle from binding to cell surface receptors to viral-cell fusion, replication, assembly, and release of the virus from the host cell that antiviral polymers interfere with to block viral infections.

Critical media attributes in E-beam sterilization of corneal tissue.

When ionizing irradiation interacts with a media, it can form reactive species that can react with the constituents of the system, leading to eradication of bioburden and sterilization of the tissue. Understanding the media's properties such as polarity is important to control and direct those reactive species to perform desired reactions. Using ethanol as a polarity modifier of water, we herein generated a series of media with varying relative polarities for electron beam (E-beam) irradiation of cornea at 25 kGy and studied how the irradiation media's polarity impacts properties of the cornea. After irradiation of corneal tissues, mechanical (tensile strength and modulus, elongation at break, and compression modulus), chemical, optical, structural, degradation, and biological properties of the corneal tissues were evaluated. Our study showed that irradiation in lower relative polarity media improved structural properties of the tissues yet reduced optical transmission; higher relative polarity reduced structural and optical properties of the cornea; and intermediate relative polarity (ethanol concentrations = 20-30% (v/v)) improved the structural properties, without compromising optical characteristics. Regardless of media polarity, irradiation did not negatively impact the biocompatibility of the corneal tissue. Our data shows that the absorbed ethanol can be flushed from the irradiated cornea to levels that are nontoxic to corneal and retinal cells. These findings suggest that the relative polarity of the irradiation media can be tuned to generate sterilized tissues, including corneal grafts, with engineered properties that are required for specific biomedical applications. STATEMENT OF SIGNIFICANCE: Extending the shelf-life of corneal tissue can improve general accessibility of cornea grafts for transplantation. Irradiation of donor corneas with E-beam is an emerging technology to sterilize the corneal tissues and enable their long-term storage at room temperature. Despite recent applications in clinical medicine, little is known about the effect of irradiation and preservation media's characteristics, such as polarity on the properties of irradiated corneas. Here, we have showed that the polarity of the media can be a valuable tool to change and control the properties of the irradiated tissue for transplantation.

Systematic optimization of visible light-induced crosslinking conditions of gelatin methacryloyl (GelMA).

Gelatin methacryloyl (GelMA) is one of the most widely used photo-crosslinkable biopolymers in tissue engineering. In in presence of an appropriate photoinitiator, the light activation triggers the crosslinking process, which provides shape fidelity and stability at physiological temperature. Although ultraviolet (UV) has been extensively explored for photo-crosslinking, its application has been linked to numerous biosafety concerns, originated from UV phototoxicity. Eosin Y, in combination with TEOA and VC, is a biosafe photoinitiation system that can be activated via visible light instead of UV and bypasses those biosafety concerns; however, the crosslinking system needs fine-tuning and optimization. In order to systematically optimize the crosslinking conditions, we herein independently varied the concentrations of Eosin Y [(EY)], triethanolamine (TEOA), vinyl caprolactam (VC), GelMA precursor, and crosslinking times and assessed the effect of those parameters on the properties the hydrogel. Our data showed that except EY, which exhibited an optimal concentration (~ 0.05 mM), increasing [TEOA], [VA], [GelMA], or crosslinking time improved mechanical (tensile strength/modulus and compressive modulus), adhesion (lap shear strength), swelling, biodegradation properties of the hydrogel. However, increasing the concentrations of crosslinking reagents ([TEOA], [VA], [GelMA]) reduced cell viability in 3-dimensional (3D) cell culture. This study enabled us to optimize the crosslinking conditions to improve the properties of the GelMA hydrogel and to generate a library of hydrogels with defined properties essential for different biomedical applications.

Biomechanical Testing of Flanged Polypropylene Sutures in Scleral Fixation.

OBJECTIVE: To optimize the flanged belt-loop technique of scleral fixation through biomechanical testing and report clinical outcomes of resultant modifications. DESIGN: Experimental study. METHODS: The force to disinsert flanged polypropylene suture from human cadaveric sclera was assessed using a tensile testing machine and compared to the breaking strengths of 9-0 and 10-0 polypropylene. The effects of modifying suture gauge (5-0, 6-0, 7-0, or 8-0), amount of suture cauterized (0.5 or 1.0 mm), and sclerotomy size (27, 30, 32, 33 gauge) were investigated. Belt-loop intrascleral fixation using 6-0 and 7-0 polypropylene with 30 and 32 gauge needles, respectively, was performed in 4 patients. Main outcome measures were flanged suture disinsertion forces in cadaveric sclera. RESULTS: The average force to disinsert a flange created by melting 1.0 mm of 5-0, 6-0, 7-0, and 8-0 polypropylene suture from human cadaveric sclera via 27, 30, 32, and 33 gauge needle sclerotomies was 3.0 ± 0.5 N, 2.1 ± 0.3 N, 0.9 ± 0.2 N, and 0.4 ± 0.1 N, respectively. The disinsertion forces for flanges formed by melting 0.5 mm of the same gauges were 72%-79% lower (P < .001). In comparison, the breaking strengths of 9-0 and 10-0 polypropylene were 0.91 ± 0.4 N and 0.52 ± 0.03 N. Belt-loop fixation using 6-0 and 7-0 polypropylene with 30 and 32 gauge sclerotomies demonstrated good outcomes at 6 months. CONCLUSIONS: The flanged belt-loop technique is a biomechanically sound method of scleral fixation using 1.0 mm flanges of 5-0 to 7-0 polypropylene paired with 27, 30, and 32 gauge sclerotomies. In contrast, 8-0 polypropylene and 0.5 mm flanges of any suture gauge will likely be unstable with this technique.

A Biomechanical Study of Flanged Intrascleral Haptic Fixation of Three-Piece Intraocular Lenses.

PURPOSE: Flanged intrascleral haptic fixation (FISHF) is a useful method for securing intraocular lenses (IOLs) in eyes without capsular support. Biomechanical studies were conducted to support the use of this technique. DESIGN: Laboratory investigation. METHODS: Haptics of 3-piece IOLs were passed through cadaveric human sclera using 30- and 27-gauge needles. Flanges were created by melting 1.0 mm from the haptic ends using cautery. The forces required to remove the flanged haptic from the sclera and disinsert the haptic from the optic were measured using a mechanical tester and a custom-fabricated mount. RESULTS: The mean FISHF dislocation force using 30-gauge needles was greatest with the CT Lucia 602 (2.04 ± 0.24 newtons [N]) compared to the LI61AO (0.93 ± 0.41 N; P = .001), ZA9003 (0.70 ± 0.34 N; P = <.001), and MA60AC (0.27 ± 0.19 N; P <.001). Using 27-gauge needles with the CT Lucia resulted in a lower dislocation force (0.56 ± 0.36 N; P <.001). The FISHF dislocation force was correlated with the flange-to-needle diameter ratio (r = 0.975). The FISHF dislocation forces of the CT Lucia and LI61AO using 30-gauge needles were not significantly different from their haptic-optic disinsertion forces (P = .79 and .27, respectively). There were no differences in flange diameters between 1.0 mm and 2.0 mm haptic melt lengths across the IOLs (P = .15-.85). CONCLUSIONS: These data strongly support the biomechanical stability of FISHF with the polyvinylidene fluoride haptics of the CT Lucia using small diameter instruments for the creation of an intrascleral tunnel. 1.0 mm of haptic may be the optimal melt length.

Graphene-Lined Porous Gelatin Glycidyl Methacrylate Hydrogels: Implications for Tissue Engineering.

Despite rigorous research, inferior mechanical properties and structural homogeneity are the main challenges constraining hydrogel's suturability to host tissue and limiting its clinical applications. To tackle those, we developed a reverse solvent interface trapping method, in which organized, graphene-coated microspherical cavities were introduced into a hydrogel to create heterogeneity and make it suturable. To generate those cavities, (i) graphite exfoliates to graphene sheets, which spread at the water/ heptane interfaces of the microemulsion, (ii) heptane fills the microspheres coated by graphene, and (iii) a cross-linkable hydrogel dissolved in water fills the voids. Cross-linking solidifies such microemulsion to a strong, suturable, permanent hybrid architecture, which has better mechanical properties, yet it is biocompatible and supports cell adhesion and proliferation. These properties along with the ease and biosafety of fabrication suggest the potential of this strategy to enhance tissue engineering outcomes by generating various suturable scaffolds for biomedical applications, such as donor cornea carriers for Boston keratoprosthesis (BK).

Photo-cross-linked Gelatin Glycidyl Methacrylate/N-Vinylpyrrolidone Copolymeric Hydrogel with Tunable Mechanical Properties for Ocular Tissue Engineering Applications.

Corneal transplantation is currently the primary treatment for corneal blindness. However, severe global scarcity of donor corneas is driving the scientific community to find novel solutions. One potential solution is to replace the damaged tissue with a biocompatible artificial cornea. Here, gelatin glycidyl methacrylate (GM) and N-vinylpyrrolidone (VP) were cocrosslinked to afford a hybrid bicomponent copolymeric hydrogel with excellent mechanical, structural, and biological properties. Our studies showed that the GM/VP ratio can be adjusted to generate a construct with high tensile modulus and strength of 1.6 and 1.0 MPa, respectively, compared to 14 and 7.5 MPa for human cornea. The construct can tolerate up to 22.4 kPa pressure before retention sutures can tear through it. Due to the presence of a synthetic component, it has a significantly higher stability against collagenase induced degradation, yet it is biocompatible and promotes cellular adhesion, proliferation, and migration under in vitro settings.

Tuning gelatin-based hydrogel towards bioadhesive ocular tissue engineering applications.

Gelatin based adhesives have been used in the last decades in different biomedical applications due to the excellent biocompatibility, easy processability, transparency, non-toxicity, and reasonable mechanical properties to mimic the extracellular matrix (ECM). Gelatin adhesives can be easily tuned to gain different viscoelastic and mechanical properties that facilitate its ocular application. We herein grafted glycidyl methacrylate on the gelatin backbone with a simple chemical modification of the precursor, utilizing epoxide ring-opening reactions and visible light-crosslinking. This chemical modification allows the obtaining of an elastic protein-based hydrogel (GELGYM) with excellent biomimetic properties, approaching those of the native tissue. GELGYM can be modulated to be stretched up to 4 times its initial length and withstand high tensile stresses up to 1.95 MPa with compressive strains as high as 80% compared to Gelatin-methacryloyl (GeIMA), the most studied derivative of gelatin used as a bioadhesive. GELGYM is also highly biocompatible and supports cellular adhesion, proliferation, and migration in both 2 and 3-dimensional cell-cultures. These characteristics along with its super adhesion to biological tissues such as cornea, aorta, heart, muscle, kidney, liver, and spleen suggest widespread applications of this hydrogel in many biomedical areas such as transplantation, tissue adhesive, wound dressing, bioprinting, and drug and cell delivery.