A gelatin based antioxidant enriched biomaterial by grafting and saturation: Towards sustained drug delivery from antioxidant matrix

Tailoring photobiomodulation to enhance tissue regeneration

Photobiomodulation (PBM), the use of biocompatible tissue-penetrating light to interact with intracellular chromophores to modulate the fates of cells and tissues, has emerged as a promising non-invasive approach to enhancing tissue regeneration. Unlike photodynamic or photothermal therapies that require the use of photothermal agents or photosensitizers, PBM treatment does not need external agents. With its non-harmful nature, PBM has demonstrated efficacy in enhancing molecular secretions and cellular functions relevant to tissue regeneration. The utilization of low-level light from various sources in PBM targets cytochrome c oxidase, leading to increased synthesis of adenosine triphosphate, induction of growth factor secretion, activation of signaling pathways, and promotion of direct or indirect gene expression. When integrated with stem cell populations, bioactive molecules or nanoparticles, or biomaterial scaffolds, PBM proves effective in significantly improving tissue regeneration. This review consolidates findings from in vitro, in vivo, and human clinical outcomes of both PBM alone and PBM-combined therapies in tissue regeneration applications. It encompasses the background of PBM invention, optimization of PBM parameters (such as wavelength, irradiation, and exposure time), and understanding of the mechanisms for PBM to enhance tissue regeneration. The comprehensive exploration concludes with insights into future directions and perspectives for the tissue regeneration applications of PBM.

Extracellular Matrix-Mimetic Intrinsic Versatile Coating Derived from Marine Adhesive Protein Promotes Diabetic Wound Healing through Regulating the Microenvironment

The management of diabetic wound healing remains a severe clinical challenge due to the complicated wound microenvironments, including abnormal immune regulation, excessive reactive oxygen species (ROS), and repeated bacterial infections. Herein, we report an extracellular matrix (ECM)-mimetic coating derived from scallop byssal protein (Sbp9Δ), which can be assembled in situ within 30 min under the trigger of Ca2+ driven by strong coordination interaction. The biocompatible Sbp9Δ coating and genetically programmable LL37-fused coating exhibit outstanding antioxidant, antibacterial, and immune regulatory properties in vitro. Proof-of-concept applications demonstrate that the coating can reliably promote wound healing in animal models, including diabetic mice and rabbits, ex vivo human skins, and Staphylococcus aureus-infected diabetic mice. In-depth mechanism investigation indicates that improved wound microenvironments accelerated wound repair, including alleviated bacterial infection, lessened inflammation, appearance of abundant M2-type macrophages, removal of ROS, promoted angiogenesis, and re-epithelialization. Collectively, our investigation provides an in situ, convenient, and effective approach for diabetic wound repair.

Molecular Mechanisms and Applications of Polyphenol-Protein Complexes with Antioxidant Properties: A Review

Proteins have been extensively studied for their outstanding functional properties, while polyphenols have been shown to possess biological activities such as antioxidant properties. There is increasing clarity about the enhanced functional properties as well as the potential application prospects for the polyphenol-protein complexes with antioxidant properties. It is both a means of protein modification to provide enhanced antioxidant capacity and a way to deliver or protect polyphenols from degradation. This review shows that polyphenol-protein complexes could be formed via non-covalent or covalent interactions. The methods to assess the complex's antioxidant capacity, including scavenging free radicals and preventing lipid peroxidation, are summarized. The combination mode, the type of protein or polyphenol, and the external conditions will be the factors affecting the antioxidant properties of the complexes. There are several food systems that can benefit from the enhanced antioxidant properties of polyphenol-protein complexes, including emulsions, gels, packaging films, and bioactive substance delivery systems. Further validation of the cellular and in vivo safety of the complexes and further expansion of the types and sources of proteins and polyphenols for forming complexes are urgently needed to be addressed. The review will provide effective information for expanding applications of proteins and polyphenols in the food industry.

3D Scaffolds Fabrication via Bicomponent Microgels Assembly: Process Optimization and In Vitro Characterization

In the last decade, different technological approaches have been proposed for the fabrication of 3D models suitable to evaluate in vitro cell response. Among them, electro fluid dynamic atomization (EFDA) belonging to the family of electro-assisted technologies allows for the dropping of polysaccharides and/or proteins solutions to produce micro-scaled hydrogels or microgels with the peculiar features of hydrogel-like materials (i.e., biocompatibility, wettability, swelling). In this work, a method to fabricate 3D scaffolds by the assembly of bicomponent microgels made of sodium alginate and gelatin was proposed. As first step, optical and scanning electron microscopy with the support of image analysis enabled to explore the basic properties of single blocks in terms of correlation between particle morphology and process parameters (i.e., voltage, flow rate, electrode gap, and needle diameter). Chemical analysis via ninhydrin essays and FTIR analysis confirmed the presence of gelatin, mostly retained by physical interactions into the alginate network mediated by electrostatic forces. In vitro tests confirmed the effect of biochemical signals exerted by the protein on the biological response of hMSCs cultured onto the microgels surface. Hence, it is concluded that alginate/gelatin microgels assemblies can efficiently work as 3D scaffolds able to support in vitro cells functions, thus providing a friendly microenvironment to investigate in vitro cell interactions.

Exploration of sea anemone-inspired high-performance biomaterials with enhanced antioxidant activity

Antioxidant biomaterials have attracted much attention in various biomedical fields because of their effective inhibition and elimination of reactive oxygen species (ROS) in pathological tissues. However, the difficulty in ensuring biocompatibility, biodegradability and bioavailability of antioxidant materials has limited their further development. Novel bioavailable antioxidant materials that are derived from natural resources are urgently needed. Here, an integrated multi-omics method was applied to fabricate antioxidant biomaterials. A key cysteine-rich thrombospondin-1 type I repeat-like (TSRL) protein was efficiently discovered from among 1262 adhesive components and then used to create a recombinant protein with a yield of 500 mg L^-1. The biocompatible TSRL protein was able to self-assemble into either a water-resistant coating through Ca²⁺-mediated coordination or redox-responsive hydrogels with tunable physical properties. The TSRL-based hydrogels showed stronger 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rates than glutathione (GSH) and ascorbic acid (Aa) and protected cells against external oxidative stress significantly more effectively. When topically applied to mice skin, TSRL alleviated epidermal hyperplasia and suppressed the degradation of collagen and elastic fibers caused by ultraviolet radiation B (UVB) irradiation, confirming that it enhanced antioxidant activity in vivo. This is the first study to successfully characterize natural antioxidant biomaterials created from marine invertebrate adhesives, and the findings indicate the excellent prospects of these biomaterials for great applications in tissue regeneration and cosmeceuticals.

Bioactive compounds of Copaifera sp. impregnated into three-dimensional gelatin dressings

This study investigates the immersion impregnation process of the copaiba oleoresin and leaf extract into Spongostan^TM gelatin dressings to be used in wound healing treatment. Copaiba oleoresin and leaf extract were characterized by spectroscopic analyses in order to confirm the identity of bioactive compounds and their compatibility with dressing material. Their antibacterial properties were evaluated and oleoresin activity against Escherichia coli and Staphylococcus aureus bacteria was confirmed while the leaf extract showed activity against S. aureus. Solubility assays in organic solvents revealed that copaiba oleoresin is miscible into dichloromethane, while leaf extract showed a 20 g/ml solubility coefficient at 35 °C in the same solvent. These miscibility and solubility conditions were selected for the impregnation process. Using the organic solvent immersion method, 11 mg of copaiba oleoresin and 19 mg of leaf extract were impregnated into 1 cm³ of 3D matrix. The main bioactives from copaiba products, such as β-caryophyllene and lupeol, were tracked in the gelatin dressing. DSC and TGA assays showed no thermal changes in the samples after impregnation. Furthermore, the spatial organization of foam structure of the dressings was preserved after superficial distribution of oleoresin, as well as amorphous-like particulate deposition of leaf extract. The main compound of copaiba oleoresin, β-caryophyllene, which exhibits well-known anti-inflammatory activities, and the main compound of copaiba leaf extract, lupeol, also an anti-inflammatory agent, were successfully impregnated using organic solvent in wound dressings and are promising for further application on tissue wound healing. Graphical Abstract.

Recent advances in phenolic-protein conjugates: synthesis, characterization, biological activities and potential applications

Proteins and phenolic compounds are two types of food ingredients with distinct functionalities. In the past decade, many attempts have been made to conjugate phenolic compounds with proteins through covalent linkages. Four types of conjugation reactions including alkaline, free radical mediated grafting, enzyme catalyzed grafting and chemical coupling methods are frequently used to synthesize phenolic-protein conjugates. The synthesized phenolic-protein conjugates can be well characterized by several different instrumental methods, such as UV spectroscopy, Fourier transform infrared spectroscopy, fluorescence spectroscopy, circular dichroism, mass spectroscopy, sodium dodecyl sulfate polyacrylamide gel electrophoresis and differential scanning calorimetry. Importantly, phenolic-protein conjugates exhibit improved biological properties (e.g. antioxidant, anticancer and antimicrobial activities) as compared with native proteins. Moreover, the applications of native proteins can be greatly widened by conjugation with phenolic compounds. Phenolic-protein conjugates have been developed as antioxidant emulsions for nutraceutical delivery, edible films for food packaging, stabilizers for metal nanoparticles, and hydrogels and nanoparticles for controlled drug release. In this review, recent advances in the synthesis, characterization, biological properties and potential applications of phenolic-protein conjugates were summarized.

Virus-Incorporated Biomimetic Nanocomposites for Tissue Regeneration

Owing to the astonishing properties of non-harmful viruses, tissue regeneration using virus-based biomimetic materials has been an emerging trend recently. The selective peptide expression and enrichment of the desired peptide on the surface, monodispersion, self-assembly, and ease of genetic and chemical modification properties have allowed viruses to take a long stride in biomedical applications. Researchers have published many reviews so far describing unusual properties of virus-based nanoparticles, phage display, modification, and possible biomedical applications, including biosensors, bioimaging, tissue regeneration, and drug delivery, however the integration of the virus into different biomaterials for the application of tissue regeneration is not yet discussed in detail. This review will focus on various morphologies of virus-incorporated biomimetic nanocomposites in tissue regeneration and highlight the progress, challenges, and future directions in this area.

Effects of thermosensitive chitosan-gelatin based hydrogel containing glutathione on Cisd2-deficient chondrocytes under oxidative stress

Aging is considered as a primary risk factor in the development of osteoarthritis (OA) which associated with mitochondrial dysfunction and oxidative stress. CDGSH iron sulfur domain 2 (Cisd2) deficiency causes mitochondrial dysfunction and drive premature aging. In the present study, thermosensitive chitosan-gelatin based hydrogel containing glutathione was developed as injectable drug delivery system for administration by minimal invasive surgery for the treatment of OA. Cisd2 deficiency (Cisd2^-/-) mouse induced pluripotent stem cells-derived chondrocytes were established and characterized. The results suggested that 100μM of glutathione may be an optimal concentration to treat Cisd2^-/- chondrocytes without cytotoxicity. The developed hydrogel showed sustained release profile of the glutathione and could decrease the reactive oxygen species level. Post-treatment of glutathione-loaded hydrogel could rescue Cisd2^-/- chondrocytes from oxidative damage via increasing catalase activity, down-regulation of inflammation, and decreasing apoptosis. These results suggest that thermosensitive glutathione-loaded hydrogel may be a potential antioxidant therapeutic strategy for treating Cisd2^-/- chondrocytes in the near future.

Gelatin-Graphene Nanocomposites with Ultralow Electrical Percolation Threshold

Gelatin-graphene conductive biopolymer nanocomposites (CPCs) with ultralow percolation threshold are designed by reducing in situ graphene oxide nanosheets with ascorbic acid and suppressing the aggregation of the graphene nanosheets. The resulting conductive nanocomposites show a record-low electrical percolation threshold of 3.3 × 10(-2) vol%, which arises from the homogeneous dispersion of the graphene nanosheets within the gelatin matrix.

Gallic acid grafting effect on delivery performance and antiglaucoma efficacy of antioxidant-functionalized intracameral pilocarpine carriers

Functionalization of therapeutic carrier biomaterials can potentially provide additional benefits in drug delivery for disease treatment. Given that this modification determines final therapeutic efficacy of drug carriers, here, we investigate systematically the role of grafting amount of antioxidant gallic acid (GA) onto GN in situ gelling copolymers made of biodegradable gelatin and thermo-responsive poly(N-isopropylacrylamide) for intracameral delivery of pilocarpine in antiglaucoma treatment. As expected, increasing redox reaction time increased total antioxidant activities and free radical scavenging abilities of synthesized carrier biomaterials. The hydrophilic nature of antioxidant molecules strongly affected physicochemical properties of carrier materials with varying GA grafting amounts, thereby dictating in vitro release behaviors and mechanisms of pilocarpine. In vitro oxidative stress challenges revealed that biocompatible carriers with high GA content alleviated lens epithelial cell damage and reduced reactive oxygen species. Intraocular pressure and pupil diameter in glaucomatous rabbits showed correlations with GA-mediated release of pilocarpine. Additionally, enhanced pharmacological treatment effects prevented corneal endothelial cell loss during disease progression. Increasing GA content increased total antioxidant level and decreased nitrite level in the aqueous humor, suggesting a much improved antioxidant status in glaucomatous eyes. This work significantly highlights the dependence of physicochemical properties, drug release behaviors, and bioactivities on intrinsic antioxidant capacities of therapeutic carrier biomaterials for glaucoma treatment.

STATEMENT OF SIGNIFICANCE

Development of injectable biodegradable polymer depots and functionalization of carrier biomaterials with antioxidant can potentially provide benefits such as improved bioavailability, controlled release pattern, and increased therapeutic effect in intracameral pilocarpine administration for glaucoma treatment. For the first time, this study demonstrated that the biodegradable in situ gelling copolymers can incorporate different levels of antioxidant gallic acid to tailor the structure-property-function relationship of the intracameral drug delivery system. The systematic evaluation fully verified the dependence of phase transition, degradation behavior, drug release mechanism, and antiglaucoma efficacy on intrinsic antioxidant capacities of carrier biomaterials. The report highlights the significant role of grafting amount of gallic acid in optimizing performance of antioxidant-functionalized polymer therapeutics as new drug delivery platforms in disease treatment.

An emulsion of pigmented nanoceria as a medicinal cosmetic

In this work, SnO₂functionalized graphene oxide was shown to possess high adsorption capacities and fast adsorption rates for organic dyes over wide pH ranges. Additionally, the adsorbent could be easily regenerated by washing with ethanol.