Benlysta-Loaded Sodium Alginate Hydrogel and Its Selective Functions in Promoting Skin Cell Growth and Inhibiting Inflammation

Hydrogel-based approaches to target hypersensitivity mechanisms underlying autoimmune disease

A robust adaptive immune response is essential for combatting pathogens. In the wrong context such as due to genetic and environmental factors, however, the same mechanisms crucial for self-preservation can lead to a loss of self-tolerance. Resulting autoimmunity manifests in the development of a host of organ-specific or systemic autoimmune diseases, hallmarked by aberrant immune responses and tissue damage. The prevalence of autoimmune diseases is on the rise, medical management of which focuses primarily on pharmacological immunosuppression that places patients at a risk of side effects, including opportunistic infections and tumorigenesis. Biomaterial-based drug delivery systems confer many opportunities to address challenges associated with conventional disease management. Hydrogels, in particular, can protect encapsulated cargo (drug or cell therapeutics) from the host environment, afford their presentation in a controlled manner, and can be tailored to respond to disease conditions or support treatment via multiplexed functionality. Moreover, localized delivery to affected sites by these approaches has the potential to concentrate drug action at the site, reduce off-target exposure, and enhance patient compliance by reducing the need for frequent administration. Despite their many benefits for the management of autoimmune disease, such biomaterial-based approaches focus largely on the downstream effects of hypersensitivity mechanisms and have a limited capacity to eradicate the disease. In contrast, direct targeting of mechanisms of hypersensitivity reactions uniquely enables prophylaxis or the arrest of disease progression by mitigating the basis of autoimmunity. One promising approach is to induce self-antigen-specific tolerance, which specifically subdues damaging autoreactivity while otherwise retaining the normal immune responses. In this review, we will discuss hydrogel-based systems for the treatment of autoimmune disease, with a focus on those that target hypersensitivity mechanisms head-on. As the field continues to advance, it will expand the range of therapeutic choices for people coping with autoimmune diseases, providing fresh prospects for better clinical outcomes and improved quality of life.

Hydrogel-Based Skin Regeneration

The skin is subject to damage from the surrounding environment. The repair of skin wounds can be very challenging due to several factors such as severe injuries, concomitant infections, or comorbidities such as diabetes. Different drugs and wound dressings have been used to treat skin wounds. Tissue engineering, a novel therapeutic approach, revolutionized the treatment and regeneration of challenging tissue damage. This field includes the use of synthetic and natural biomaterials that support the growth of tissues or organs outside the body. Accordingly, the demand for polymer-based therapeutic strategies for skin tissue defects is significantly increasing. Among the various 3D scaffolds used in tissue engineering, hydrogel scaffolds have gained special significance due to their unique properties such as natural mimicry of the extracellular matrix (ECM), moisture retention, porosity, biocompatibility, biodegradability, and biocompatibility properties. First, this article delineates the process of wound healing and conventional methods of treating wounds. It then presents an examination of the structure and manufacturing methods of hydrogels, followed by an analysis of their crucial characteristics in healing skin wounds and the most recent advancements in using hydrogel dressings for this purpose. Finally, it discusses the potential future advancements in hydrogel materials within the realm of wound healing.

Sustained release of alginate hydrogel containing antimicrobial peptide Chol-37(F34-R) in vitro and its effect on wound healing in murine model of Pseudomonas aeruginosa infection

BACKGROUND

Antibiotic resistance is a significant public health concern around the globe. Antimicrobial peptides exhibit broad-spectrum and efficient antibacterial activity with an added advantage of low drug resistance. The higher water content and 3D network structure of the hydrogels are beneficial for maintaining antimicrobial peptide activity and help to prevent degradation. The antimicrobial peptide released from hydrogels also hasten the local wound healing by promoting epithelial tissue regeneration and granulation tissue formation.

OBJECTIVE

This study aimed at developing sodium alginate based hydrogel loaded with a novel antimicrobial peptide Chol-37(F34-R) and to investigate the characteristics in vitro and in vivo as an alternative antibacterial wound dressing to treat infectious wounds.

METHODS

Hydrogels were developed and optimized by varying the concentrations of crosslinkers and subjected to various characterization tests like cross-sectional morphology, swelling index, percent water contents, water retention ratio, drug release and antibacterial activity in vitro, and Pseudomonas aeruginosa infected wound mice model in vivo.

RESULTS

The results indicated that the hydrogel C proved superior in terms of cross-sectional morphology having uniformly sized interconnected pores, a good swelling index, with the capacity to retain a higher quantity of water. Furthermore, the optimized hydrogel has been found to exert a significant antimicrobial activity against bacteria and was also found to prevent bacterial infiltration into the wound site due to forming an impermeable barrier between the wound bed and external environment. The optimized hydrogel was found to significantly hasten skin regeneration in animal models when compared to other treatments in addition to strong inhibitory effect on the release of pro-inflammatory cytokines (interleukin-1β and tumor necrosis factor-α).

CONCLUSIONS

Our results suggest that sodium alginate -based hydrogels loaded with Chol-37(F34-R) hold the potential to be used as an alternative to conventional antibiotics in treating infectious skin wounds.

Response of cardiovascular environment to sulfonated hyaluronic acid with higher sulfur content

Sulfonated hyaluronic acid (S-HA) has been shown to promote endothelialization in the treatment of cardiovascular diseases according to amounts of investigations. In this study, two kinds of S-HA with higher sulfur content were obtained successfully. Through a series of cell experiments, it was found that the S-HA with higher sulfur content not only possessed stronger ability of promoting the growth and migration of endothelial cells, regulating the phenotype of smooth muscle cells, but also had stronger anti-inflammatory function. Furthermore, all the S-HA molecules are very compatible with blood.

Arbutin Inhibited Heat Stress-Induced Apoptosis and Promoted Proliferation and Migration of Heat-Injured Dermal Fibroblasts and Keratinocytes by Activating PI3K/AKT Signaling Pathway

Objective. Studies have shown that arbutin has antioxidant and anti-inflammatory activities, which makes it suitable for treating skin wounds. We designed this study to investigate the effect of arbutin on heat-induced apoptosis, proliferation, and migration of dermal fibroblasts and keratinocytes and to explore the molecular mechanism. Methods. In vitro, HaCAT and dermal fibroblast (DFL) cells were cultured and used to establish a heat stress-injured skin cell model. We investigated the effects of arbutin on apoptosis, proliferation, and migration of HaCAT and DFL cells after heat stress injury. We then used immunoblotting to detect the expression of p-PI3K, PI3K, p-AKT, and AKT proteins for studying the underlying mechanisms and used a PI3K/AKT inhibitor (LY294002) to verify the efficacy of arbutin in HaCAT and DFL cells with heat stress injury. Results. Arbutin strongly inhibited heat stress-induced apoptosis, proliferation inhibition, and migration inhibition of HaCAT and DFL cells in vitro. Our results also showed that arbutin strongly decreased the ratio of Bax/Bcl2 protein expression and PCNA protein expression in HaCAT and DFL cells after treatment with heat stress. Furthermore, we also found that arbutin significantly increased the ratio of p-PI3K/PI3K and p-AKT/AKT protein expression, and LY294002 markedly reversed the effect of arbutin on heat stress-induced apoptosis, proliferation inhibition, and migration inhibition of HaCAT and DFL cells. Conclusion. Our finding indicated that arbutin inhibited heat stress-induced apoptosis and promoted proliferation and migration of heat-injured dermal fibroblasts and epidermal cells by activating the PI3K/AKT signaling pathway, suggesting that arbutin may provide an alternative therapeutic approach for the treatment of skin injury.

Advances in Hyaluronic Acid for Biomedical Applications

Hyaluronic acid (HA) is a large non-sulfated glycosaminoglycan that is the main component of the extracellular matrix (ECM). Because of its strong and diversified functions applied in broad fields, HA has been widely studied and reported previously. The molecular properties of HA and its derivatives, including a wide range of molecular weights but distinct effects on cells, moisture retention and anti-aging, and CD44 targeting, promised its role as a popular participant in tissue engineering, wound healing, cancer treatment, ophthalmology, and cosmetics. In recent years, HA and its derivatives have played an increasingly important role in the aforementioned biomedical fields in the formulation of coatings, nanoparticles, and hydrogels. This article highlights recent efforts in converting HA to smart formulation, such as multifunctional coatings, targeted nanoparticles, or injectable hydrogels, which are used in advanced biomedical application.

Designing a new alginate-fibrinogen biomaterial composite hydrogel for wound healing

Wound healing is a complex process and rapid healing necessitates a proper micro-environment. Therefore, design and fabrication of an efficacious wound dressing is an impressive innovation in the field of wound healing. The fabricated wound dressing in this scenario was designed using a combination of the appropriate coagulating and anti-bacterial materials like fibrinogen (as coagulating agent), nisin (as anti-bacterial agent), ethylenediaminetetraacetic acid (as anti-bacterial agent), and alginate (as wound healing agent). Biophysical characterization showed that the interaction of fibrinogen and alginate was associated with minor changes in the secondary structure of the protein. Conformational studies showed that the protein was structurally stable at 42 °C, is the maximum temperature of the infected wound. The properties of the hydrogel such as swelling, mechanical resistance, nisin release, antibacterial activity, cytotoxicity, gel porosity, and blood coagulation were assessed. The results showed a slow release for the nisin during 48 h. Antibacterial studies showed an inhibitory effect on the growth of Gram-negative and Gram-positive bacteria. The hydrogel was also capable to absorb a considerable amount of water and provide oxygenation as well as incorporation of the drug into its structure due to its sufficient porosity. Scanning electron microscopy showed pore sizes of about 14–198 µm in the hydrogel. Cell viability studies indicated high biocompatibility of the hydrogel. Blood coagulation test also confirmed the effectiveness of the synthesized hydrogel in accelerating the process of blood clot formation. In vivo studies showed higher rates of wound healing, re-epithelialization, and collagen deposition. According to the findings from in vitro as well as in vivo studies, the designed hydrogel can be considered as a novel attractive wound dressing after further prerequisite assessments.

Preparation of microspheres by alginate purified from Sargassum horneri and study of pH-responsive behavior and drug release

Alginate is a biopolymer used in numerous biomedical applications. The current work describes the purification of alginate from Sargassum horneri and method optimization for formulating drug-loaded microparticles by water-in-oil emulsification/internal gelation. Molecular weights of S. horneri alginate were ranging 50-70 kDa. Among 16 method optimizations, the F4 method was selected for further studies based on shape descriptor parameters which indicated, 0.24 ± 0.01 circularity, 0.80 ± 0.11 roundness, 1.27 ± 0.20 aspect ratio between long and short axis, and less aggregation in PBS. Processing parameters of the F4 method were; CaCO3/alginate ratio of 20/1 (w/w), 5% span 80 in oil (v/v), water/oil phase ratio of 1/20 (v/v), and 1000 rpm emulsification speed. Hollow pores were visible on the surface of dehydrated F4 microparticles. F4 microparticles indicated 41.84 ± 2.93 and 45.86 ± 1.65% encapsulation efficiencies for phloroglucinol (F4P) and indomethacin (F4I) with 32.69 ± 1.35 and 31.69 ± 1.98% loading capacities. These microparticles were found to be desirable for extending drug release over short periods (0-3 days) under pH 2.0-7.4. F4P and F4I were effective in suppressing intracellular reactive oxygen species in FD exposed HaCaT cells while increasing cell viability over 24 - 48 h duration.

Improved Osteogenesis by Mineralization Combined With Double-Crosslinked Hydrogel Coating for Proliferation and Differentiation of Mesenchymal Stem Cells

In consideration of improving the interface problems of poly-L-lactic acid (PLLA) that hindered biomedical use, surface coatings have been explored as an appealing strategy in establishing a multi-functional coating for osteogenesis. Though the layer-by-layer (LBL) coating developed, a few studies have applied double-crosslinked hydrogels in this technique. In this research, we established a bilayer coating with double-crosslinked hydrogels [alginate–gelatin methacrylate (GelMA)] containing bone morphogenic protein (BMP)-2 [alginate-GelMA/hydroxyapatite (HA)/BMP-2], which displayed great biocompatibility and osteogenesis. The characterization of the coating showed improved properties and enhanced wettability of the native PLLA. To evaluate the biosafety and inductive ability of osteogenesis, the behavior (viability, adherence, and proliferation) and morphology of human bone mesenchymal stem cells (hBMSCs) on the bilayer coatings were tested by multiple exams. The satisfactory function of osteogenesis was verified in bilayer coatings. We found the best ratios between GelMA and alginate for biological applications. The Alg70-Gel30 and Alg50-Gel50 groups facilitated the osteogenic transformation of hBMSCs. In brief, alginate-GelMA/HA/BMP-2 could increase the hBMSCs’ early transformation of osteoblast lineage and promote the osteogenesis of bone defect, especially the outer hydrogel layer such as Alg70-Gel30 and Alg50-Gel50.

Hydrogel Preparation Methods and Biomaterials for Wound Dressing

Wounds have become one of the causes of death worldwide. The metabolic disorder of the wound microenvironment can lead to a series of serious symptoms, especially chronic wounds that bring great pain to patients, and there is currently no effective and widely used wound dressing. Therefore, it is important to develop new multifunctional wound dressings. Hydrogel is an ideal dressing candidate because of its 3D structure, good permeability, excellent biocompatibility, and ability to provide a moist environment for wound repair, which overcomes the shortcomings of traditional dressings. This article first briefly introduces the skin wound healing process, then the preparation methods of hydrogel dressings and the characteristics of hydrogel wound dressings made of natural biomaterials and synthetic materials are introduced. Finally, the development prospects and challenges of hydrogel wound dressings are discussed.

Polymeric Hydrogel Scaffolds: Skin Tissue Engineering and Regeneration

Tissue engineering is a novel regenerative approach in the medicinal field that promises the regeneration of damaged tissues. Moreover, tissue engineering involves synthetic and natural biomaterials that facilitate tissue or organ growth outside the body. Not surprisingly, the demand for polymer-based therapeutical approaches in skin tissue defects has increased at an effective rate, despite the pressing clinical need. Among the 3D scaffolds for tissue engineering and regeneration approaches, hydrogel scaffolds have shown significant importance for their use as 3D cross-linked scaffolds in skin tissue regeneration due to their ideal moisture retention property and porosity biocompatibility, biodegradable, and biomimetic characteristics. In this review, we demonstrated the choice of ideal biomaterials to fabricate the novel hydrogel scaffolds for skin tissue engineering. After a short introduction to the bioactive and drug-loaded polymeric hydrogels, the discussion turns to fabrication and characterisation techniques of the polymeric hydrogel scaffolds. In conclusion, we discuss the excellent wound healing potential of stem cell-loaded hydrogels and Nano-based approaches to designing hydrogel scaffolds for skin tissue engineering.

Sodium alginate/collagen hydrogel loaded with human umbilical cord mesenchymal stem cells promotes wound healing and skin remodeling

Stem cell transplantation is a promising therapy for wound healing, but the low retention and survival of transplanted stem cells limit their application. Injectable hydrogels exert beneficial effects in skin tissue engineering. In this study, an injectable hydrogel composed of sodium alginate (SA) and collagen type I (Col) was synthesized as a tissue scaffold to improve the efficacy of stem cells in a full-thickness excision wound model. Our results showed that SA/Col hydrogel was injectable, biodegradable, and exhibited low immunogenicity, which could promote the retention and survival of hUC-MSCs in vivo. SA/Col loaded with hUC-MSCs showed reduced wound size (p < 0.05). Histological and immunofluorescence results confirmed that SA/Col loaded with hUC-MSCs significantly promoted the formation of granulation, enhanced collagen deposition and angiogenesis, increased VEGF and TGF-β1 expression (p < 0.05), and mitigated inflammation evidenced by lower production of TNF-α and IL-1β and higher release of IL-4 and IL-10 (p < 0.05). Furthermore, SA/Col loaded with hUC-MSCs significantly lowered the expression of NLRP3 inflammasome-related proteins (p < 0.05). Taken together, our results suggest that SA/Col loaded with hUC-MSCs promotes skin wound healing via partly inhibiting NLRP3 pathway, which has potential to the treatment of skin wounds.