EGF and curcumin co-encapsulated nanoparticle/hydrogel system as potent skin regeneration agent

Polymer Applied in Hydrogel Wound Dressing for Wound Healing: Modification/Functionalization Method and Design Strategies

Hydrogel wound dressings have emerged as a promising solution for wound healing due to their excellent mechanical and biochemical properties. Over recent years, there has been significant progress in expanding the variety of raw materials used for hydrogel formulation along with the development of advanced modification techniques and design approaches that enhance their performance. However, a comprehensive review encompassing diverse polymer modification strategies and design innovations for hydrogel dressings is still lacking in the literature. This review summarizes the use of natural polymers (e.g., chitosan, gelatin, sodium alginate, hyaluronic acid, and dextran) and synthetic polymers (e.g., poly(vinyl alcohol), polyethylene glycol, Pluronic F-127, poly(N-isopropylacrylamide), polyacrylamide, and polypeptides) in hydrogel wound dressings. We further explore the advantages and limitations of these polymers and discuss various modification strategies, including cationic modification, oxidative modification, double-bond modification, catechol modification, etc. The review also addresses design principles and synthesis methods, aligning polymer modifications with specific requirements in wound healing. Finally, we discuss future challenges and opportunities in the development of advanced hydrogel-based wound dressings.

Comparative effects of epidermal and fibroblast growth factor-infused collagen patches on wound healing in a full-thickness rat model

OBJECTIVE

This study aimed to investigate the effects of Epidermal Growth Factor (EGF)- and Fibroblast Growth Factor (FGF)-infused collagen patches on wound healing in an experimental rat model. The focus was on acute and chronic inflammation, granulation tissue formation, fibroblast maturation, re-epithelialization, neovascularization, and collagen remodeling.

METHODS

Full-thickness cranial wounds (12 mm) were created on the dorsal regions of 21 male Wistar rats and divided into four groups: Group 1 (collagen patch alone), Group 2 (collagen + EGF), Group 3 (collagen + FGF). The kaudal defects served as a chronic wound model with secondary intention healing, monitored for 21 days. Tissue biopsies were collected on days 3, 7, and 21. Histopathological evaluation included inflammation scores, granulation tissue formation, fibroblast maturation, re-epithelialization, neovascularization, and Type 1/Type 3 collagen ratio. Data were analyzed using one-way ANOVA, Kruskal-Wallis test, and other appropriate post hoc tests. Statistical significance was set at p < 0.05.

RESULTS

Acute inflammation significantly decreased in Group 3 on day 7 (p = 0.001), while chronic inflammation was minimal by day 21 in Groups 1 and 3. Group 2 showed the highest granulation tissue formation on day 21 (p < 0.05). Fibroblast maturation peaked in Group 3 on day 21 (p = 0.004). Re-epithelialization was complete in Groups 1 and 3 by day 21, significantly outperforming Group 2 (p < 0.005). Group 3 demonstrated superior collagen deposition and the highest Type 1/Type 3 collagen ratio (p < 0.05).

CONCLUSIONS

FGF-infused collagen patches significantly improved fibroblast maturation, epithelialization, and collagen remodeling, outperforming EGF and standalone collagen patches. These findings highlight the potential of FGF as a therapeutic agent in wound healing.

A reactive oxygen species-responsive hydrogel loaded with Apelin-13 promotes the repair of spinal cord injury by regulating macrophage M1/M2 polarization and neuroinflammation

Spinal cord injury (SCI) is a chronic condition whereby persistent aberrant macrophage activation hinders the repair process. During acute trauma, dominant M1 macrophages produce high levels of reactive oxygen species (ROS), leading to increased apoptosis in neurons, glial cells, and oligodendrocytes. This study investigated the specific effects of a ROS-responsive hydrogel loaded with Apelin-13 (Apelin-13@ROS-hydrogel) on macrophage polarization and neuroinflammation, thereby exploring its role in boosting SCI repair. Apelin-13@ROS-hydrogel was prepared, and its ROS-scavenging capacities were evaluated using DPPH, H2O2, and ·O2- assays. The effects of Apelin-13@ROS-hydrogel on macrophage polarization, inflammatory mediators and oxidative stress were assessed in LPS-pre-treated microglia BV2 cells and an SCI rat model. Apelin-13 was downregulated in SCI rats. Treatment with Apelin-13 improved functional recovery and reduced inflammatory factors and M1 markers but increased the M2 marker Arg-1. Apelin-13@ROS-hydrogel showed significantly higher ROS-scavenging capacities compared to the control hydrogel. Apelin-13@ROS-hydrogel decreased pro-inflammatory mediators and increased anti-inflammatory mediators in BV2 cells. Apelin-13@ROS-hydrogel enhanced the healing process and neurological functions, reducing inflammatory factors and M1 markers while increasing Arg-1 levels by day 28 in SCI rats. Collectively, Apelin-13 enhances SCI repair through macrophage regulation, M1/M2 polarization, and neuroinflammation. The ROS-responsive hydrogel further amplifies these effects, offering a promising therapeutic strategy for SCI.

Nanoparticles Perspective in Skin Tissue Engineering: Current Concepts and Future Outlook

Nanotechnology seems to provide solutions to the unresolved complications in skin tissue engineering. According to the broad function of nanoparticles, this review article is intended to build a perspective for future success in skin tissue engineering. In the present review, recent studies were reviewed, and essential benefits and challenging issues regarding the application of nanoparticles in skin tissue engineering were summarized. Previous studies indicated that nanoparticles can play essential roles in the improvement of engineered skin. Bio-inspired design of an engineered skin structure first needs to understand the native tissue and mimic that in laboratory conditions. Moreover, a fundamental comprehension of the nanoparticles and their related effects on the final structure can guide researchers in recruiting appropriate nanoparticles. Attention to essential details, including the designation of nanoparticle type according to the scaffold, how to prepare the nanoparticles, and what concentration to use, is critical for the application of nanoparticles to become a reality. In conclusion, nanoparticles were applied to promote scaffold characteristics and angiogenesis, improve cell behavior, provide antimicrobial conditions, and cell tracking.

Advances in proteins, polysaccharides, and composite biomaterials for enhanced wound healing via microenvironment management: A review

Wound management is crucial yet imposes substantial social and economic burdens on patients and healthcare systems. The recent rapid advancements in biomaterials and manufacturing technology have created favorable conditions for expediting wound healing. This review examines the latest developments in biomacromolecule-based wound dressings, with a particular focus on proteins and polysaccharides, and their role in modulating the wound microenvironment. The importance of extracellular matrix (ECM)-inspired materials, such as hydrogels and biomimetic dressings, is emphasized. Additionally, this review explores the functionalization of wound dressings, emphasizing properties such as hemostatic capabilities, pain relief, antimicrobial activity, and innovative smart functions like electroceuticals and wound condition monitoring. The study integrates discussions on both the macroscopic healing outcomes and the microscopic pathophysiological mechanisms, highlighting recent advances in managing wound environments to expedite healing. Finally, the review critically assesses the challenges associated with the clinical translation of these wound-healing materials in the future.

Pickering Emulsion of Curcumin Stabilized by Cellulose Nanocrystals/Chitosan Oligosaccharide: Effect in Promoting Wound Healing

Background: The stabilization of droplets in Pickering emulsions using solid particles has garnered significant attention through various methods. Cellulose and chitin derivatives in nature offer a sustainable source of Pickering emulsion stabilizers. Methods: In this study, medium-chain triglycerides were used as the oil phase for the preparation of emulsion. This study explores the potential of cellulose nanocrystals (CNC) and shell oligosaccharides (COS) as effective stabilizers for achieving stable Pickering emulsions. Optical microscopy, CLSM, and Cyro-SEM were employed to analyze CNC/COS-Cur, revealing the formation of bright and uniform yellow spherical emulsions. Results: CLSM and SEM results confirmed that CNC/COS formed a continuous and compact shell at the oil-water interface layer, enabling a stable 2~3 microns Pickering emulsion with CNS/COS-Cur as an oil-in-water emulsion stabilizer. Based on FTIR, XRD, and SEM analyses of CNC/COS, along with zeta potential measurements of the emulsion, we found that CNC and COS complexed via electrostatic adsorption, forming irregular rods measuring approximately 200-300 nm in length. An evaluation of the DPPH radical-scavenging ability demonstrated that the CNC/ COS-Cur Pickering emulsion performed well in vitro. In vivo experiments involving full-thickness skin excision surgery in rats revealed that CNC/COS-Cur facilitated wound repair processes. Measurements of the MDA and SOD content in healing tissues indicated that the CNC/COS-Cur Pickering emulsion increased SOD levels and reduced MDA content, effectively countering oxidative stress-induced damage. An assessment based on wound-healing rates and histopathological examination showed that CNC/COS-Cur promoted granulation tissue formation, fibroblast proliferation, angiogenesis, and an accelerated re-epithelialization process within the wound tissue, leading to enhanced collagen deposition and facilitating rapid wound-healing capabilities. An antibacterial efficacy assessment conducted in vitro demonstrated antibacterial activity.

Growth factors and growth factor gene therapies for treating chronic wounds

Chronic wounds are an unmet clinical need affecting millions of patients globally, and current standards of care fail to consistently promote complete wound closure and prevent recurrence. Disruptions in growth factor signaling, a hallmark of chronic wounds, have led researchers to pursue growth factor therapies as potential supplements to standards of care. Initial studies delivering growth factors in protein form showed promise, with a few formulations reaching clinical trials and one obtaining clinical approval. However, protein-form growth factors are limited by instability and off-target effects. Gene therapy offers an alternative approach to deliver growth factors to the chronic wound environment, but safety concerns surrounding gene therapy as well as efficacy challenges in the gene delivery process have prevented clinical translation. Current growth factor delivery and gene therapy approaches have primarily used single growth factor formulations, but recent efforts have aimed to develop multi-growth factor approaches that are better suited to address growth factor insufficiencies in the chronic wound environment, and these strategies have demonstrated improved efficacy in preclinical studies. This review provides an overview of chronic wound healing, emphasizing the need and potential for growth factor therapies. It includes a summary of current standards of care, recent advances in growth factor, cell-based, and gene therapy approaches, and future perspectives for multi-growth factor therapeutics.

Advancements in Regenerative Hydrogels in Skin Wound Treatment: A Comprehensive Review

This state-of-the-art review explores the emerging field of regenerative hydrogels and their profound impact on the treatment of skin wounds. Regenerative hydrogels, composed mainly of water-absorbing polymers, have garnered attention in wound healing, particularly for skin wounds. Their unique properties make them well suited for tissue regeneration. Notable benefits include excellent water retention, creating a crucially moist wound environment for optimal healing, and facilitating cell migration, and proliferation. Biocompatibility is a key feature, minimizing adverse reactions and promoting the natural healing process. Acting as a supportive scaffold for cell growth, hydrogels mimic the extracellular matrix, aiding the attachment and proliferation of cells like fibroblasts and keratinocytes. Engineered for controlled drug release, hydrogels enhance wound healing by promoting angiogenesis, reducing inflammation, and preventing infection. The demonstrated acceleration of the wound healing process, particularly beneficial for chronic or impaired healing wounds, adds to their appeal. Easy application and conformity to various wound shapes make hydrogels practical, including in irregular or challenging areas. Scar minimization through tissue regeneration is crucial, especially in cosmetic and functional regions. Hydrogels contribute to pain management by creating a protective barrier, reducing friction, and fostering a soothing environment. Some hydrogels, with inherent antimicrobial properties, aid in infection prevention, which is a crucial aspect of successful wound healing. Their flexibility and ability to conform to wound contours ensure optimal tissue contact, enhancing overall treatment effectiveness. In summary, regenerative hydrogels present a promising approach for improving skin wound healing outcomes across diverse clinical scenarios. This review provides a comprehensive analysis of the benefits, mechanisms, and challenges associated with the use of regenerative hydrogels in the treatment of skin wounds. In this review, the authors likely delve into the application of rational design principles to enhance the efficacy and performance of hydrogels in promoting wound healing. Through an exploration of various methodologies and approaches, this paper is poised to highlight how these principles have been instrumental in refining the design of hydrogels, potentially revolutionizing their therapeutic potential in addressing skin wounds. By synthesizing current knowledge and highlighting potential avenues for future research, this review aims to contribute to the advancement of regenerative medicine and ultimately improve clinical outcomes for patients with skin wounds.

MXene-based polysaccharide aerogel with multifunctional enduring antimicrobial effects for infected wound healing

Wound infection is a predominant etiological factor contributing to delayed wound healing in open wounds. Hence, it holds paramount clinical significance to devise wound dressings endowed with superior antibacterial properties. In this study, a Schiff base-crosslinked aerogel comprising sodium alginate oxide (OSA), carboxymethyl chitosan (CMCS), and Nb2C@Ag/PDA (NAP) was developed. The resultant OSA/CMCS-Nb2C@Ag/PDA (OC/NAP) composite aerogel exhibited commendable attributes including exceptional swelling characteristics, porosity, biocompatibility, and sustained antimicrobial efficacy. In vitro antimicrobial assays unequivocally demonstrated that the OC/NAP composite aerogel maintained nearly 100 % inhibition of Staphylococcus aureus and Escherichia coli under an 808 nm laser even after 25 h. Crucially, the outcomes of in vivo infected wound healing experiments demonstrated that the wound healing rate of the OC/NAP composite aerogel group reached approximately 100 % within a span of 14 days, which was significantly greater than that of the blank control group. In vitro and in vivo hemostatic experiments also revealed that the composite aerogel had excellent hemostatic properties. The results of this study demonstrate the remarkable potential of OC/NAP aerogel as a multifunctional clinical wound dressing, especially for infected wounds.

Hyaluronic acid hydrogel for controlled release of heterobifunctional photocleavable linker-modified epidermal growth factor in wound healing

Peptide and protein drugs, such as epidermal growth factor (EGF), face challenges related to stability and bioavailability. Recently, hydrogels have emerged as promising carriers for these drugs. This study focuses on a light-responsive hydrogel-based drug delivery system for the controlled release of EGF in wound healing. A photocleavable (PC) linker was designed to bind EGF to the hydrogel matrix, enabling UV light-triggered release of EGF. Hydrogels have evolved from drug reservoirs to controlled release systems, and the o-nitrobenzyl-based PC linkers offer selective cleavage under UV irradiation. We used a thiol-ene crosslinked hyaluronic acid (HA) hydrogel matrix modified with the PC-linked EGF. The release of EGF from the HA hydrogel under UV irradiation was evaluated, along with in vitro and in vivo experiments to assess the controlled effect of EGF on wound healing. Our results indicate that the successful development of a light-responsive hydrogel-based system for precise temporal release of EGF enhances the therapeutic potential in wound healing. This study highlights the importance of incorporating stimulus-responsive functionalities into hydrogel-based drug delivery systems to optimize protein drugs in clinical applications.

Research progress related to thermosensitive hydrogel dressings in wound healing: a review

Wound healing is a dynamic and complex process in which the microenvironment at the wound site plays an important role. As a common material for wound healing, dressings accelerate wound healing and prevent external wound infections. Hydrogels have become a hot topic in wound-dressing research because of their high water content, good biocompatibility, and adjustable physical and chemical properties. Intelligent hydrogel dressings have attracted considerable attention because of their excellent environmental responsiveness. As smart polymer hydrogels, thermosensitive hydrogels can respond to small temperature changes in the environment, and their special properties make them superior to other hydrogels. This review mainly focuses on the research progress in thermosensitive intelligent hydrogel dressings for wound healing. Polymers suitable for hydrogel formation and the appropriate molecular design of the hydrogel network to achieve thermosensitive hydrogel properties are discussed, followed by the application of thermosensitive hydrogels as wound dressings. We also discuss the future perspectives of thermosensitive hydrogels as wound dressings and provide systematic theoretical support for wound healing.

Why traditional herbal medicine promotes wound healing: Research from immune response, wound microbiome to controlled delivery

Impaired wound healing in chronic wounds has been a significant challenge for clinicians and researchers for decades. Traditional herbal medicine (THM) has a long history of promoting wound healing, making them culturally accepted and trusted by a great number of people in the world. However, for a long time, the understanding of herbal medicine has been limited and incomplete, particularly in the allopathic medicine-dominated research system. The therapeutic effects of individual components isolated from THM are found less pronounced compared to synthetic chemical medicine, and the clinical efficacy is always inferior to herbs. In the present article, we review and discuss underlying mechanisms of the skin microbiome involved in the wound healing process; THM in regulating immune responses and commensal microbiome. We additionally propose few pioneer ideas and studies in the development of therapeutic strategies for controlled delivery of herbal medicine. This review aims to promote wound care with a focus on wound microbiome, immune response, and topical drug delivery systems. Finally, future development trends, challenges, and research directions are discussed.

EGF, a veteran of wound healing: highlights on its mode of action, clinical applications with focus on wound treatment, and recent drug delivery strategies

Epidermal growth factor (EGF) has been used in wound management and regenerative medicine since the late 1980s. It has been widely utilized for a long time and still is because of its excellent tolerability and efficacy. EGF has many applications in tissue engineering, cancer therapy, lung diseases, gastric ulcers, and wound healing. Nevertheless, its in vivo and during storage stability is a primary concern. This review focuses on the topical use of EGF, especially in chronic wound healing, the emerging use of biomaterials to deliver it, and future research possibilities. To successfully deliver EGF to wounds, a delivery system that is proteolytically resistant and stable over the long term is required. Biomaterials are an area of interest for the development of such systems. These systems may be used in non-healing wounds such as diabetic foot ulcers, pressure ulcers, and burns. In these pathologies, EGF can reduce the risk of amputation of the lower extremities, as it accelerates the wound healing process. Furthermore, appropriate delivery system would also stabilize and control the EGF release profile in a wound. Several in vitro and in vivo studies have already proven the efficacy of such systems in the above-mentioned types of wounds. Moreover, several formulations such as ointments and intralesional injections are already available on the market. However, these products are still problematic in terms of inadequate diffusion of EGF, low bioavailability storage conditions, and shelf-life. This review discusses the nano formulations comprising biomaterials infused with EGF which could be a promising delivery system for chronic wound healing in the future.

Next-Generation Hydrogels as Biomaterials for Biomedical Applications: Exploring the Role of Curcumin

Since the first report on the pharmacological activity of curcumin in 1949, enormous amounts of research have reported diverse activities for this natural polyphenol found in the dietary spice turmeric. However, curcumin has not yet been used for human application as an approved drug. The clinical translation of curcumin has been hampered due to its low solubility and bioavailability. The improvement in bioavailability and solubility of curcumin can be achieved by its formulation using drug delivery systems. Hydrogels with their biocompatibility and low toxicity effects have shown a substantial impact on the successful formulation of hydrophobic drugs for human clinical trials. This review focuses on hydrogel-based delivery systems for curcumin and describes its applications as anti-cancer as well as wound healing agents.

Xanthan gum/oil body-microgel emulsions with enhanced transdermal absorption for accelerating wound healing

The oil body comprises lipid droplets surrounded by a surface embedded with oil body-related proteins. To form a drug delivery system, an oleosin can be fused with foreign proteins and bound to the oil body surface. Here, safflower oil bodies carrying oleosin-human epidermal growth factor (hEGF) were mixed with xanthan gum to form self-assembled polymers, referred as an oil body microgel emulsion (OBEME) without any chemical crosslinking agent. The physicochemical properties of OBEME were evaluated and compared with those of natural lipid droplets. The electrostatic interaction between xanthan gum and oil bodies prevents excessive cross-linking and forms a uniform network structure. The basic properties of OBEME were characterized by scanning electron microscopy, cryo-scanning electron microscopy, rheology, and thermogravimetric analysis. The OBEME is an interconnected network and presents a smooth surface without any pores; it remains stable at room temperature for 90 days, and is not affected by low-speed centrifugation and repeated freeze-thaw cycles as indicated by particle size, potential, and fluorescence microscopy analyses. The OBEME enlarges the skin tissue gap, enhances skin permeability, and shows a good slow-release effect in the transdermal absorption test in vivo. It demonstrates a wound healing effect; further, it regulates the inflammatory response of full-layer skin wounds in rats, as well as accelerate angiogenesis, and promote re-epithelialization and remodeling. The OBEME as a bioactive molecule-carbohydrate complex can effectively accelerate skin regeneration and has great translational potential to provide low-cost alternative wound care treatments.

Anti-inflammatory hydrogel dressings and skin wound healing

Hydrogels are promising and widely utilized in the biomedical field. In recent years, the anti-inflammatory function of hydrogel dressings has been significantly improved, addressing many clinical challenges presented in ongoing endeavours to promote wound healing. Wound healing is a cascaded and highly complex process, especially in chronic wounds, such as diabetic and severe burn wounds, in which adverse endogenous or exogenous factors can interfere with inflammatory regulation, leading to the disruption of the healing process. Although insufficient wound inflammation is uncommon, excessive inflammatory infiltration is an almost universal feature of chronic wounds, which impedes a histological repair of the wound in a predictable biological step and chronological order. Therefore, resolving excessive inflammation in wound healing is essential. In the past 5 years, extensive research has been conducted on hydrogel dressings to address excessive inflammation in wound healing, specifically by efficiently scavenging excessive free radicals, sequestering chemokines and promoting M1 -to-M2 polarization of macrophages, thereby regulating inflammation and promoting wound healing. In this study, we introduced novel anti-inflammatory hydrogel dressings and demonstrated innovative methods for their preparation and application to achieve enhanced healing. In addition, we summarize the most important properties required for wound healing and discuss our analysis of potential challenges yet to be addressed.

Biomaterials-Based Regenerative Strategies for Skin Tissue Wound Healing

Skin tissue wound healing proceeds through four major stages, including hematoma formation, inflammation, and neo-tissue formation, and culminates with tissue remodeling. These four steps significantly overlap with each other and are aided by various factors such as cells, cytokines (both anti- and pro-inflammatory), and growth factors that aid in the neo-tissue formation. In all these stages, advanced biomaterials provide several functional advantages, such as removing wound exudates, providing cover, transporting oxygen to the wound site, and preventing infection from microbes. In addition, advanced biomaterials serve as vehicles to carry proteins/drug molecules/growth factors and/or antimicrobial agents to the target wound site. In this review, we report recent advancements in biomaterials-based regenerative strategies that augment the skin tissue wound healing process. In conjunction with other medical sciences, designing nanoengineered biomaterials is gaining significant attention for providing numerous functionalities to trigger wound repair. In this regard, we highlight the advent of nanomaterial-based constructs for wound healing, especially those that are being evaluated in clinical settings. Herein, we also emphasize the competence and versatility of the three-dimensional (3D) bioprinting technique for advanced wound management. Finally, we discuss the challenges and clinical perspective of various biomaterial-based wound dressings, along with prospective future directions. With regenerative strategies that utilize a cocktail of cell sources, antimicrobial agents, drugs, and/or growth factors, it is expected that significant patient-specific strategies will be developed in the near future, resulting in complete wound healing with no scar tissue formation.

Growth factors-based platelet lysate rejuvenates skin against ageing through NF-κB signalling pathway: In vitro and in vivo mechanistic and clinical studies

Introduction

Platelets benefit tissue regeneration by secreting growth factors, and platelet products, for example, platelet lysate (PL), have been clinically applied for tissue rejuvenation. To determine the anti‐ageing efficacy and mechanism of human PL (hPL) on skin, this study conducted clinical retrospective analysis, nude mice‐based in vivo study and human dermal fibroblasts (HDFs)‐based in vitro study.

Methods

Flow cytometry was employed for quality control of hPL, and ELISA was used for quantification of growth factors (EGF, IGF‐1, PDGF and TGF‐β) in hPL. After d‐galactose modelling, skin texture grading, histopathological observation, immunofluorescence analysis and oxidative stress assays were conducted on nude mice, while SA‐β‐gal staining, CCK‐8 and wound healing assays were conducted on HDFs. qPCR and western blot were conducted to clarify hPL's mechanism.

Results

The clinical retrospective data showed that hPL obviously rejuvenated human skin appearances without adverse events. The animal data showed that hPL exerted rejuvenative effects on skin, and the cellular data showed that hPL significantly promoted the proliferation and migration of HDFs and suppressed senescence‐associated secretory protein secretion and senescence state of senescent HDFs by suppressing NF‐κB pathway. The NF‐κB‐dependent mechanism was verified positively by using P65 siRNA and negatively by using prostratin. Furthermore, EGF, IGF‐1, PDGF and TGF‐β were found as the main ingredients in hPL, which contributed to the efficacy and mechanism of hPL.

Conclusion

This study provided novel knowledge of hPL, making it ideal for skin rejuvenation.

Engineering PD-L1 Cellular Nanovesicles Encapsulating Epidermal Growth Factor for Deep Second-Degree Scald Treatment

Scars are common and intractable consequences after scalded wound healing, while monotherapy of epidermal growth factors does not solve this problem. Maintaining the stability of epidermal growth factors and promoting scarless healing of wounds is paramount. In this study, engineering cellular nanovesicles overexpressing PD-L1 proteins, biomimetic nanocarriers with immunosuppressive efficacy, were successfully prepared to encapsulate epidermal growth factors for maintaining its bioactivity. Remarkably, PD-L1 cellular nanovesicles encapsulating epidermal growth factors (EGF@PDL1 NVs) exerted desired therapeutic effect by attenuating the overactivation of T cell immune response and promoting skin cells migration and proliferation. Hence, EGF@PD-L1 NVs promoted wound healing and prevented scarring in deep second-degree scald treatment, demonstrating a better effect than using individual PD-L1 NVs or EGF. This research proved that EGF@PD-L1 NVs is considered an innovative and thorough therapy of deep second-degree scald.

Immunomodulatory Effect of Epidermal Growth Factor Secreted by Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells on Atopic Dermatitis

Background and Objectives

Human mesenchymal stem cells (MSCs) are emerging as a treatment for atopic dermatitis (AD), a chronic inflammatory skin disorder that affects a large number of people across the world. Treatment of AD using human umbilical cord blood-derived MSCs (hUCB-MSCs) has recently been studied. However, the mechanism underlying their effect needs to be studied continuously. Thus, the objective of this study was to investigate the immunomodulatory effect of epidermal growth factor (EGF) secreted by hUCB-MSCs on AD.

Methods and Results

To explore the mechanism involved in the therapeutic effect of MSCs for AD, a secretome array was performed using culture medium of hUCB-MSCs. Among the list of genes common for epithelium development and skin diseases, we focused on the function of EGF. To elucidate the effect of EGF secreted by hUCB-MSCs, EGF was downregulated in hUCB-MSCs using EGF-targeting small interfering RNA. These cells were then co-cultured with keratinocytes, Th2 cells, and mast cells. Depletion of EGF disrupted immunomodulatory effects of hUCB-MSCs on these AD-related inflammatory cells. In a Dermatophagoides farinae-induced AD mouse model, subcutaneous injection of hUCB-MSCs ameliorated gross scoring, histopathologic damage, and mast cell infiltration. It also significantly reduced levels of inflammatory cytokines including interleukin (IL)-4, tumor necrosis factor (TNF)-α, thymus and activation-regulated chemokine (TARC), and IL-22, as well as IgE levels. These therapeutic effects were significantly attenuated at all evaluation points in mice injected with EGF-depleted hUCB-MSCs.

Conclusions

EGF secreted by hUCB-MSCs can improve AD by regulating inflammatory responses of keratinocytes, Th2 cells, and mast cells.

Microwave-Assisted Physically Cross-Linked Chitosan-Sodium Alginate Hydrogel Membrane Doped with Curcumin as a Novel Wound Healing Platform

This project purposes to develop chitosan and sodium alginate-based hydrogel membranes loaded with curcumin through microwave-based physical cross-linking technique and its evaluation for wound healing potential. For the purpose, curcumin-loaded chitosan and sodium alginate membranes were developed using microwave at fixed frequency of 2450 MHz, power 350 W for 60 s, and tested for their physicochemical attributes like swelling, erosion, surface morphology, drug content, and in vitro drug release. The membranes were also subjected to tensile strength and vibrational and thermal analysis followed by testing in vivo on animals. The results indicated that microwave treatment significantly enhanced the swelling ability, reduced the erosion, and ensured smooth surface texture with optimal drug content. The drug was released in a slow fashion releasing total of 41 ± 4.2% within 24-h period with a higher tensile strength of 16.4 ± 5.3 Mpa. The vibrational analysis results revealed significant fluidization of hydrophilic domains and defluidization of hydrophobic domains which translated into a significant rise in the melting temperature and corresponding enthalpy which were found to be 285.2 ± 3.2 °C and 4.89 ± 1.4 J/g. The in vivo testing revealed higher percent re-epithelialization (75 ± 2.3%) within 14 days of the treatment application in comparison to only gauze and other treatments applied, with higher extent of collagen deposition having well-defined epidermis and stratum corneum formation. The microwave-treated chitosan-sodium alginate hydrogel membranes loaded with curcumin may prove to be another alternative to treat skin injuries. Graphical Abstract.

Rational selection of bioactive principles for wound healing applications: Growth factors and antioxidants

Wound healing is a complex process of communication between growth factors, reactive species of oxygen, cells, signalling pathways, and cytokines in the extracellular matrix, in which growth factors are the key regulators. In humans, the main regulators of the cellular responses in wound healing are five growth factors, namely EGF, bFGF, VEGF, and TGF-β1. On the other hand, antioxidants such as astaxanthin, beta-carotene, epigallocatechin gallate, delphinidin, and curcumin have been demonstrated to stimulate cell proliferation, migration and angiogenesis, and control inflammation, to suggest a practical approach to design new strategies to treat non-healing cutaneous conditions. Based on the individual effects of growth factors and antioxidants, it may be envisioned that the use of both types of bioactives in wound healing formulations may have an additive or synergistic effect on the healing potential. This review addresses the effect of growth factors and antioxidants on wound healing-related processes. Furthermore, a prospective on their potential additive or synergistic effect on wound healing formulations, based on their individual effects, is presented. This may serve as a guide for the development of a new generation of wound healing formulations.

Injectable nanocomposite hydrogels as an emerging platform for biomedical applications: A review

Hydrogels have attracted much attention for biomedical and pharmaceutical applications due to the similarity of their biomimetic structure to the extracellular matrix of natural living tissues, tunable soft porous microarchitecture, superb biomechanical properties, proper biocompatibility, etc. Injectable hydrogels are an exciting type of hydrogels that can be easily injected into the target sites using needles or catheters in a minimally invasive manner. The more comfortable use, less pain, faster recovery period, lower costs, and fewer side effects make injectable hydrogels more attractive to both patients and clinicians in comparison to non-injectable hydrogels. However, it is difficult to achieve an ideal injectable hydrogel using just a single material (i.e., polymer). This challenge can be overcome by incorporating nanofillers into the polymeric matrix to engineer injectable nanocomposite hydrogels with combined or synergistic properties gained from the constituents. This work aims to critically review injectable nanocomposite hydrogels, their preparation methods, properties, functionalities, and versatile biomedical and pharmaceutical applications such as tissue engineering, drug delivery, and cancer labeling and therapy. The most common natural and synthetic polymers as matrices together with the most popular nanomaterials as reinforcements, including nanoceramics, carbon-based nanostructures, metallic nanomaterials, and various nanosized polymeric materials, are highlighted in this review.

Biomimetic Hydrogels to Promote Wound Healing

Wound healing is a common physiological process which consists of a sequence of molecular and cellular events that occur following the onset of a tissue lesion in order to reconstitute barrier between body and external environment. The inherent properties of hydrogels allow the damaged tissue to heal by supporting a hydrated environment which has long been explored in wound management to aid in autolytic debridement. However, chronic non-healing wounds require added therapeutic features that can be achieved by incorporation of biomolecules and supporting cells to promote faster and better healing outcomes. In recent decades, numerous hydrogels have been developed and modified to match the time scale for distinct stages of wound healing. This review will discuss the effects of various types of hydrogels on wound pathophysiology, as well as the ideal characteristics of hydrogels for wound healing, crosslinking mechanism, fabrication techniques and design considerations of hydrogel engineering. Finally, several challenges related to adopting hydrogels to promote wound healing and future perspectives are discussed.

“Nanomaterials of curcumin-hyaluronic acid”: their various methods of formulations, clinical and therapeutic applications, present gap, and future directions

Background

Nanomaterials of curcumin with hyaluronic acid have gained a lot of attention for potential therapeutic applications of curcumin and hyaluronic acid with or without other additional drugs. Overall studies of curcumin and hyaluronic acid show that nanomaterials of curcumin with hyaluronic acid accelerate the efficacy of curcumin in the treatment of various disorders like arthritis, cancer, hepatic fibrosis, neural disorders, wound healing, and skin regeneration, it is largely due to the combined effect of hyaluronic acid and curcumin. However, due to limited clinical trials and experiments on humans and animals, there is a substantial gap in research for the safety and efficacy of nanomaterials of curcumin-hyaluronic acid in the treatment of curcumin and hyaluronic acid targeted diseases and disorders.

Main body of the abstract

In this current review, we have first described various reported synthetic nanomaterials of curcumin-hyaluronic acid, then in the next section, we have described various fields, disorders, and diseases where these are being applied and in the final section of this review, we discussed the research gap, and future research directions needed to propose the fabricated nanocurcumin-hyaluronic acid biomaterials.

Short conclusion

There are substantial gaps in research for the safety and efficacy of nanomaterials of curcumin with hyaluronic acid due to limited available data of clinical trials and experiments of nanocurcumin-hyaluronic acid biomaterials on humans and animals. So, it entirely requires serious and committed efforts through the well-organized system of practical and clinical trials which provide results, data, and detections that lead to the formulation of the best drug from curcumin with hyaluronic acid for the treatment of curcumin and hyaluronic acid targeted diseases and disorders.

An intrinsically bioactive hydrogel with on-demand drug release behaviors for diabetic wound healing

Prolonged, intense inflammation and excessive oxidative stress hinder diabetic wounds from healing normally, leading to disorders downstream including the postponement of re-epithelialization and extracellular matrix (ECM) formation. Herein, we report a hyaluronic acid (HA) and chitosan based hydrogel (OHA-CMC) with inherent antibacterial and hemostatic activities fabricated via Schiff base reaction. By encapsulating nanotechnologically-modified curcumin (CNP) and epidermal growth factor (EGF) into the hydrogel, OHA-CMC/CNP/EGF exhibited extraordinary antioxidant, anti-inflammatory, and migration-promoting effects in vitro. Meanwhile, OHA-CMC/CNP/EGF presented on-demand drug release in synchrony with the phases of the wound healing process. Specifically, curcumin was rapidly and constantly released to alleviate inflammation and oxidative stress in the early phase of wound healing, while a more gradual and sustained release of EGF supported late proliferation and ECM remodeling. In a diabetic full-thickness skin defect model, OHA-CMC/CNP/EGF dramatically improved wound healing with ideal re-epithelialization, granulation tissue formation, and skin appendage regeneration, highlighting the enormous therapeutic potential this biomaterial holds as a diabetic wound dressing.

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OHA-CMC hydrogel showed excellent inherent antibacterial and hemostatic activities.

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OHA-CMC co-delivered curcumin and EGF with on-demand drug release that met the repair requirements of each healing stage.

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OHA-CMC/CNP/EGF showed potent antioxidant and anti-inflammation activities, and was capable of promoting cell migration.

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OHA-CMC/CNP/EGF significantly accelerated diabetic wound healing.

Immunomodulatory biomaterials and their application in therapies for chronic inflammation-related diseases

The degree of tissue injuries such as the level of scarring or organ dysfunction, and the immune response against them primarily determine the outcome and speed of healing process. The successful regeneration of functional tissues requires proper modulation of inflammation-producing immune cells and bioactive factors existing in the damaged microenvironment. In the tissue repair and regeneration processes, different types of biomaterials are implanted either alone or by combined with other bioactive factors, which will interact with the immune systems including immune cells, cytokines and chemokines etc. to achieve different results highly depending on this interplay. In this review article, the influences of different types of biomaterials such as nanoparticles, hydrogels and scaffolds on the immune cells and the modification of immune-responsive factors such as reactive oxygen species (ROS), cytokines, chemokines, enzymes, and metalloproteinases in tissue microenvironment are summarized. In addition, the recent advances of immune-responsive biomaterials in therapy of inflammation-associated diseases such as myocardial infarction, spinal cord injury, osteoarthritis, inflammatory bowel disease and diabetic ulcer are discussed.

Therapeutic effects of EGF-modified curcumin/chitosan nano-spray on wound healing

Dermal injury, including trauma, surgical incisions, and burns, remain the most prevalent socio-economical health care issue in the clinic. Nanomedicine represents a reliable administration strategy that can promote the healing of skin lesions, but the lack of effective drug delivery methods can limit its effectiveness. In this study, we developed a novel nano-drug delivery system to treat skin defects through spraying. We prepared curcumin-loaded chitosan nanoparticles modified with epidermal growth factor (EGF) to develop an aqueous EGF-modified spray (EGF@CCN) for the treatment of dermal wounds. In vitro assays showed that the EGF@CCN displayed low cytotoxicity, and that curcumin was continuously and slowly released from the EGF@CCN. In vivo efficacy on wound healing was then evaluated using full-thickness dermal defect models in Wistar rats, showing that the EGF@CCN had significant advantages in promoting wound healing. On day 12 post-operation, skin defects in the rats of the EGF@CCN group were almost completely restored. These effects were related to the activity of curcumin and EGF on skin healing, and the high compatibility of the nano formulation. We therefore conclude that the prepared nano-scaled EGF@CCN spray represents a promising strategy for the treatment of dermal wounds.

Dermal toxicity, dermal irritation, and delayed contact sensitization evaluation of oil body linked oleosin-hEGF microgel emulsion via transdermal drug delivery for wound healing

Objective: The expression of therapeutic proteins in plant oil body bioreactors has attracted much attention. But its safety is not yet clear. This article determines the risk of safety after using the drug. Methods: The oil body-linked oleosin-hEGF microgel emulsion (OBEME) was prepared by mixing the xanthan gum with suitable concentrations in an appropriate proportion. Skin irritation and sensitization reaction were investigated in rats and guinea pigs using OBEME as test article.Results: The OBEME did not produce dermal erythema/eschar or oedema responses. The dermal subacute and subchronic toxicity of OBEME were evaluated in accordance with OECD guidelines. Compared with the control group, the basic physical signs, such as weight, feed, drinking, excretion, and behaviour of experimental animals, were not abnormal. In addition, no abnormality was found in haematological parameters, biochemical indexes, relative organ weight, and histopathological observation of organs, and there was no significant difference compared with normal saline treatment group. Therefore, we conclude that OBEME has no toxic effects and is safe and reliable to be used for topical application.

Wound dressings as growth factor delivery platforms for chronic wound healing

Introduction: Years of tissue engineering research have clearly demonstrated the potential of integrating growth factors (GFs) into scaffolds for tissue regeneration, a concept that has recently been applied to wound dressings. The old concept of wound dressings that only take a passive role in wound healing has now been overtaken, and advanced dressings which can take an active part in wound healing, are of current research interest.Areas covered: In this review we will focus on the recent strategies for the delivery of GFs to wound sites with an emphasis on the different approaches used to achieve fine tuning of spatial and temporal concentrations to achieve therapeutic efficacy.Expert opinion: The use of GFs to accelerate wound healing and reduce scar formation is now considered a feasible therapeutic approach in patients with a high risk of infections and complications. The integration of micro - and nanotechnologies into wound dressings could be the key to overcome the inherent instability of GFs and offer adequate control over the release rate. Many investigations have led to encouraging outcomes in various in vitro and in vivo wound models, and it is expected that some of these technologies will satisfy clinical needs and will enter commercialization.

EGFR-conjugated hydrogel accelerates wound healing on ulcer-induced burn wounds by targeting collagen and inflammatory cells using photoimmunomodulatory inhibition

In the present study, we fabricated an epidermal growth factor receptor (EGFR)-conjugated hydrogel to promote wound healing in cold restraint-induced gastric ulceration on burn wounds targeting collagen and inflammatory cells for the treatment of burns and gastric ulcers. Cytotoxicity and cell proliferation assays demonstrated good biocompatibility of hydrogel as a suitable extracellular matrix for targeted cells and support for regenerative cell growth. These findings were confirmed by staining methods. In vitro wound healing was confirmed cell migration in the targeted cells. The effect of the EGFR-H was investigated in cold restraint-induced gastric ulcers in rats, where the treatment was started immediately after ulcer induction. In the in vivo experiment, the EGFR-H demonstrated enhanced ulcer healing ability and less scarring compared to the hydrogel alone and controls. Thus, EGFR-H promotes healing of cold restraint-induced gastric ulcer via EGFR conjugated with a hydrogel. The present study demonstrates a novel pathway to fabricate hydrogels as suitable wound dressing biomaterials to improve deep partial thickness burn wound healing and prevent scar formation when aided by laser therapy.

Formulation and Evaluation of Microwave-Modified Chitosan-Curcumin Nanoparticles-A Promising Nanomaterials Platform for Skin Tissue Regeneration Applications Following Burn Wounds

Improved physicochemical properties of chitosan-curcumin nanoparticulate carriers using microwave technology for skin burn wound application are reported. The microwave modified low molecular weight chitosan variant was used for nanoparticle formulation by ionic gelation method nanoparticles analyzed for their physicochemical properties. The antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa cultures, cytotoxicity and cell migration using human dermal fibroblasts-an adult cell line-were studied. The microwave modified chitosan variant had significantly reduced molecular weight, increased degree of deacetylation and decreased specific viscosity. The nanoparticles were nano-sized with high positive charge and good dispersibility with entrapment efficiency and drug content in between 99% and 100%, demonstrating almost no drug loss. Drug release was found to be sustained following Fickian the diffusion mechanism for drug release with higher cumulative drug release observed for formulation (F)2. The microwave treatment does not render a destructive effect on the chitosan molecule with the drug embedded in the core of nanoparticles. The optimized formulation precluded selected bacterial strain colonization, exerted no cytotoxic effect, and promoted cell migration within 24 h post application in comparison to blank and/or control application. Microwave modified low molecular weight chitosan-curcumin nanoparticles hold potential in delivery of curcumin into the skin to effectively treat skin manifestations.

An EGF- and Curcumin-Co-Encapsulated Nanostructured Lipid Carrier Accelerates Chronic-Wound Healing in Diabetic Rats

Nanostructured lipid carriers (NLC) are capable of encapsulating hydrophilic and lipophilic drugs. The present study developed an NLC containing epidermal growth factor (EGF) and curcumin (EGF–Cur-NLC). EGF–Cur-NLC was prepared by a modified water-in-oil-in-water (w/o/w) double-emulsion method. The EGF–Cur-NLC particles showed an average diameter of 331.8 nm and a high encapsulation efficiency (81.1% and 99.4% for EGF and curcumin, respectively). In vitro cell studies were performed using two cell types, NIH 3T3 fibroblasts and HaCaT keratinocytes. The results showed no loss of bioactivity of EGF in the NLC formulation. In addition, EGF–Cur-NLC improved in vitro cell migration, which mimics the wound healing process. Finally, EGF–Cur-NLC was evaluated in a chronic wound model in diabetic rats. We found that EGF–Cur-NLC accelerated wound closure and increased the activity of antioxidant enzymes. Overall, these results reveal the potential of the NLC formulation containing EGF and curcumin to promote healing of chronic wounds.

Polymer-Based Materials Loaded with Curcumin for Wound Healing Applications

Some of the currently used wound dressings have interesting features such as excellent porosity, good water-absorbing capacity, moderate water vapor transmission rate, high drug loading efficiency, and good capability to provide a moist environment, but they are limited in terms of antimicrobial properties. Their inability to protect the wound from microbial invasion results in wound exposure to microbial infections, resulting in a delayed wound healing process. Furthermore, some wound dressings are loaded with synthetic antibiotics that can cause adverse side effects on the patients. Natural-based compounds exhibit unique features such as good biocompatibility, reduced toxicity, etc. Curcumin, one such natural-based compound, has demonstrated several biological activities such as anticancer, antibacterial and antioxidant properties. Its good antibacterial and antioxidant activity make it beneficial for the treatment of wounds. Several researchers have developed different types of polymer-based wound dressings which were loaded with curcumin. These wound dressings displayed excellent features such as good biocompatibility, induction of skin regeneration, accelerated wound healing processes and excellent antioxidant and antibacterial activity. This review will be focused on the in vitro and in vivo therapeutic outcomes of wound dressings loaded with curcumin.

Size effect of human epidermal growth factor-conjugated polystyrene particles on cell proliferation

Conjugation of growth factors to a carrier is a favorable method to improve their efficacy as therapeutic molecules. Here, we report the carrier size effect on bioactivity of human epidermal growth factor (hEGF) conjugated to polystyrene particles. BALB/3T3 cells were treated with hEGF-conjugated particles (hEGF-conjs) sized from 20 to 1000 nm. At hEGF concentrations less than 0.5 ng ml^-1, free hEGF was more potent than the hEGF-conjs at inducing cell proliferation. However, cell proliferation was size-dependent at higher concentrations of hEGF i.e. hEGF-conjs sized equal to or less than 200 nm displayed lower cell proliferation, compared to free hEGF, but larger particles showed increased cell proliferation. This is in agreement with previous studies showing accumulation of activated-EGFRs in early endosomes triggers apoptosis of A431 and HeLa cells. The confocal microscopy and co-localization fluorescence staining showed the 500 and 1000 nm hEGF-conjs exclusively remained on the cell surface, probably enabling them to activate EGF receptors for a longer time. Conversely, smaller particles were mostly inside the cells, indicating their rapid endocytosis. Similarly, A431 cells treated with 20 nm hEGF-conj, endocytosed the particles and experienced decreased cell proliferation, while the 500 and 1000 nm hEGF-conjs were not internalized, and induced partial cell proliferation. Moreover, we showed multivalency of hEGF-conjs is not the cause of enhanced cell proliferation by large particles, as the degree of EGFR phosphorylation by free EGF was higher, compared to hEGF-conjs. Our results suggest the potential of micron-sized particles as a carrier for hEGF to enhance cell proliferation, which could be explored as a promising approach for topical application of growth factors for accelerating wound healing.

Topical delivery of growth factors and metal/metal oxide nanoparticles to infected wounds by polymeric nanoparticles: an overview

INTRODUCTION

Infected chronic wounds particularly diabetic foot ulcers (DFUs) can result from stable colonization of antibiotic-resistant bacteria and fungi at the wound sites. In this context, the rapid healing of infected wounds has been the main goal in recent investigations. This issue can be solved by improving wound-healing phases including hemostasis, inflammatory, proliferative, and remodeling/maturation, and removal of bacteria and fungi. The applications of growth factors (GFs) and metal/metal oxide nanoparticles (MNPs/MONPs) are two choices for these targets. However, the lack of sustainable release of these agents is an important problem for appropriate wound healing.

AREA COVERED

The present review is focused on recent advances in delivery systems composed of growth factor and MNPs/MONPs for rapid wound healing.

EXPERT OPINION

Synthetic and natural polymeric micro- and nanocarriers including polyvinylpyrrolidone (PVP) and chitosan play a vital role in the healing of infected chronic wounds. Using various derivatives of chitosan as pH-responsive polymer with basic and acidic groups can be the best option to prepare controllable and sequential GF release. However, it warrants further extensive research to solve wound-healing problems.

A nanocomposite hydrogel delivery system for mesenchymal stromal cell secretome

Background

Mesenchymal stromal cell conditioned medium (MSC-CM) contains a cocktail of bioactive factors that act synergistically to induce therapeutic effects. This has been clearly demonstrated by in vivo applications of MSC-CM, but the establishment of controlled delivery systems is an unmet requirement for clinical translation.

Methods

We developed a nanocomposite-hydrogel (NP-H) comprised of poly-L-lactide nanoparticles (NPs) embedded in gelatin/hyaluronic acid (Gel/HA) hydrogel as a delivery vehicle for MSC-CM. First, we optimized the culture conditions for bone marrow-derived MSCs using serum-containing medium (SCM) and serum-free medium (SFM) and characterized the corresponding CM (serum-containing conditioned medium (ScCM) and serum-free conditioned medium (SfCM), respectively) for its potency and xeno markers. Then we prepared a composite matrix followed by physiochemical characterization and functional assays were performed.

Results

Nanocomposite hydrogel displayed an even distribution of NPs along with high porosity (> 60%) and swelling ratios > 1500%, while its protein release pattern corresponded to a mix of degradation and diffusion kinetics. Functional evaluation of the composites was determined using MSCs and human fibroblasts (HFFs). The cells seeded directly onto the composites displayed increasing metabolic activities over time, with ScCM-NP-H groups having maximum activity. The cells treated in vitro with 5% and 10% extracts of ScCM-NP-H and SfCM-NP-H exhibited a dose- and duration-dependent response. Cell activities reduced considerably for all groups, except 10% ScCM-NP-H, which displayed a significant increase over time.

Conclusion

We observed that sustained release of MSC-CM is required to prevent dose-dependent cytotoxicity. The proposed nanocomposite hydrogel for MSC-CM delivery can open up a new array for its clinical application.

Epidermal growth factor receptor conjugated fucoidan/alginates loaded hydrogel for activating EGFR/AKT signaling pathways in colon cancer cells during targeted photodynamic therapy

In the present study, we developed epidermal growth factor receptor conjugated fucoidan/alginate loaded hydrogels for targeting the delivery of hydrogel through the signaling pathway of the epidermal growth factor receptor (EGFR) to treat colon cancer. We aim to develop a drug delivery system of chlorin e6 encapsulated in hydrogel and tag it with EFGR to target cancer cells with low toxicity and limited side effects by using photodynamic therapy (PDT). The characterization and in vitro studies were conducted to evaluate the efficiency of the EGFR-hydrogel in colon cancer cells. Also, western blot analysis was used to assess protein expression levels. The in vitro results confirmed significant cell viability, proliferation, and migration of hydrogel in colon cancer. The cellular effects of the EFGR/AKT pathway were cell proliferation, inhibition of apoptosis, cell cycle progression, and cell survival and migration of colon cancer because of significant protein expression levels. The data suggested that hydrogel appears to be a promising targeting approach-PDT for treating colon cancer. Further in vivo studies are needed to conclude the overexpression level of EGFR on cancer cells. The study concluded that EGFR-H improved the targeting efficiency of hydrogel in colon cancer.

Preparation and evaluation of curcumin grafted hyaluronic acid modified pullulan polymers as a functional wound dressing material

Curcumin grafted hyaluronic acid modified pullulan polymers (Cur-HA-SPu) by chemical conjugation was designed and prepared, and its film may be used to accelerate wound healing and help to fight infection. The synthesis of Cur-HA-SPu polymer was characterized by FT-IR, ¹H NMR and DSC. Cur-HA-SPu film has a higher swelling ratio than that of HA-SPu film. Moreover, the good biocompatibility of Cur-HA-SPu polymer was confirmed by skin irritation, cytotoxicity and hemolysis tests. Compared to Cur, the MTT and proliferation test carried out in L929 cells revealed that Cur-HA-SPu polymer showed no cytotoxicity and enhanced cell proliferation. Cur-HA-SPu polymer exhibited a certain bactericidal activity against E. coli and S. aureus. Furthermore, the materials showed antioxidant activity when DPPH method determined. Wound healing study using wistar rat model demonstrated that Cur-HA-SPu film obtained better wound healing result than that of HA-SPu film or natural healing. The above results suggest that Cur-HA-SPu film is a promising and safety formulation for accelerating skin wound healing.

A human epidermal growth factor-curcumin bandage bioconjugate loaded with mesenchymal stem cell for in vivo diabetic wound healing

Bone-marrow-derived mesenchymal stem cells (MSCs) are of growing interest for the treatment of diabetic wound healing. However, they are often associated with poor proliferation and viability at the wounded site. Here, it is reported the use of human epidermal growth factor -curcumin bandage bioconjugate (EGF-Cur B) loaded with MSCs (MSCs-EGF-Cur B) at the wounded site for diabetic wound healing. Conjugation efficiency of EGF was determined by FTIR and XPS, surface morphology was analyzed by SEM and AFM and hydrophilicity by contact angle. Chemical integrity of curcumin with the polymeric matrix was studied by FTIR and, antiinflamatory and biocompatibility of EGF-Cur B were determined by TNF α ELISA and MTT study respectively. The culture of MSCs over EGF-Cur B enhanced MSC viability and expression of transcription factors associated with the maintenance of pluripotency and self-renewal (OCT¾, SOX2, and Nanog) as compared to MSCs grown in standard conditions. Its therapeutic effect was examined on diabetic full-thickness excisional wound model in terms of size and histological examination. Synergetic combinational approach especially when treated with MSCs-EGF-Cur B significantly enhanced wound closure by increasing granulation tissue formation, collagen deposition, and angiogenesis as compared to other groups. In conclusion, biocompatible therapeutic MSCs-EGF-Cur B might have great application for diabetic wound healing in the near future.

In situ forming and reactive oxygen species-scavenging gelatin hydrogels for enhancing wound healing efficacy

The overexpression of reactive oxygen species (ROS) contributes to the pathogenesis of numerous diseases such as atherosclerosis, myocardial infarction, cancer, and chronic inflammation. Therefore, the development of materials that can locally control the adverse effects resulting from excessive ROS generation is of great significance. In this study, the antioxidant gallic acid-conjugated gelatin (GGA) was introduced into gelatin-hydroxyphenyl propionic (GH) hydrogels to create an injectable hydrogel with enhanced free radical scavenging properties compared to pure GH hydrogels. The modified hydrogels were rapidly formed by an HRP-catalyzed cross-linking reaction with high mechanical strength and biodegradability. The resulting GH/GGA hydrogels effectively scavenged the hydroxyl radicals and DPPH radicals, and the scavenging capacity could be modulated by varying GGA concentrations. Moreover, in an in vitro H₂O₂-induced ROS microenvironment, GH/GGA hydrogels significantly suppressed the oxidative damage of human dermal fibroblast (hDFBs) and preserved their viability by reducing intracellular ROS production. More importantly, the ROS scavenging hydrogel efficiently accelerated the wound healing process with unexpected regenerative healing characteristics, shown by hair follicle formation; promoted neovascularization; and highly ordered the alignment of collagen fiber in a full-thickness skin defect model. Therefore, we expect that injectable GH/GGA hydrogels can serve as promising biomaterials for tissue regeneration applications, including wound treatment and other tissue repair related to ROS overexpression. STATEMENT OF SIGNIFICANCE: Recently, many researchers have endeavored to develop injectable hydrogel matrices that can modulate the ROS level to normal physiological processes for the treatment of various diseases. Here, we designed an injectable gelatin hydrogel in which gallic acid, an antioxidant compound, was conjugated onto a gelatin polymer backbone. The hydrogels showed tunable properties and could scavenge the free radicals in a controllable manner. Because of the ROS scavenging properties, the hydrogels protected the cells from the oxidative damage of ROS microenvironment and effectively accelerated the wound healing process with high quality of healed skin. We believe that this injectable ROS scavenging hydrogel has great potential for wound treatment and tissue regeneration, where oxidative damage by ROS contributes to the pathogenesis.

Molecular mechanisms in cognitive frailty: potential therapeutic targets for oxygen-ozone treatment

In the last decade, cognitive frailty has gained great attention from the scientific community. It is characterized by high inflammation and oxidant state, endocrine and metabolic alterations, mitochondria dysfunctions and slowdown in regenerative processes and immune system, with a complex and multifactorial aetiology. Although several treatments are available, challenges regarding the efficacy and the costs persist. Here, we proposed an alternative non-pharmacological, non-side-effect, low cost therapy based on anti-inflammation, antioxidant, regenerative and anti-pathogens properties of ozone, through the activation of several molecular mechanisms (Nrf2-ARE, NF-κB, NFAT, AP-1, HIFα). We highlighted how these specific processes could be implicated in cognitive frailty to identify putative therapeutic targets for its treatment. The oxigen-ozone (O₂-O₃) therapy has never been tested for cognitive frailty. This work provides thus wide scientific background to build a consistent rationale for testing for the first time this therapy, that could modulate the immune, inflammatory, oxidant, metabolic, endocrine, microbiota and regenerative processes impaired in cognitive frailty. Although insights are needed, the O₂-O₃ therapy could represent a faster, easier, inexpensive monodomain intervention working in absence of side effects for cognitive frailty.

Silicone elastomer gel impregnated with 20(S)-protopanaxadiol-loaded nanostructured lipid carriers for ordered diabetic ulcer recovery

Inefficient diabetic ulcer healing and scar formation remain a challenge worldwide, owing to a series of disordered and dynamic biological events that occur during the process of healing. A functional wound dressing that is capable of promoting ordered diabetic wound recovery is eagerly anticipated. In this study, we designed a silicone elastomer with embedded 20(S)-protopanaxadiol-loaded nanostructured lipid carriers (PPD-NS) to achieve ordered recovery in scarless diabetic ulcer healing. The nanostructured lipid carriers were prepared through an emulsion evaporation-solidification method and then incorporated into a network of silicone elastomer to form a unique nanostructured lipid carrier-enriched gel formulation. Interestingly, the PPD-NS showed excellent in vitro anti-inflammatory and proangiogenic activity. Moreover, in diabetic mice with full-thickness skin excision wound, treatment with PPD-NS significantly promoted in vivo scarless wound healing through suppressing inflammatory infiltration in the inflammatory phase, promoting angiogenesis during the proliferation phase, and regulating collagen deposition in the remodeling phase. Hence, this study demonstrates that the developed PPD-NS could facilitate ordered diabetic wound recovery via multifunctional improvement during different wound-healing phases. This novel approach could be promising for scarless diabetic wound healing.

Vascularization strategies for skin tissue engineering

Lack of proper vascularization after skin trauma causes delayed wound healing. This has sparked the development of various tissue engineering strategies to improve vascularization.