Wound healing of different molecular weight of hyaluronan; in-vivo study

Dual cross-linked self-healing hydrogel enhanced by dopamine nanoparticles and raffinose for wound healing

A series of intricate and dynamic physiological healing processes are involved in the healing of skin wounds. Herein, a multifunctional hydrogel is firstly designed and constructed by L-arginine-grafted O-carboxymethyl chitosan (CMCA), catechol-modified oxidized hyaluronic acid (DOHA), and dopamine nanoparticles (pDA-NPs). pDA-NPs were loaded in hydrogel for inherently powerful antimicrobial properties and could be as a cross-linking agent to construct hydrogels. Raffinose (Raf) was further incorporated to obtain CMCA-DOHA-pDA2@Raf hydrogel for its function of modulating epidermal differentiation. The hydrogel has good physicochemical properties and could promote cell proliferation and migration, which shows superior hemostatic capabilities in animal models of hemorrhage. The hydrogel significantly promoted wound healing on rat skin defect models by upregulating VEGF and CD31 and decreasing IL-6 and TNF-α, stimulating neovascularization and collagen deposition in epithelial structures. This multifunctional hydrogel implies the potential to be a dynamic wound dressing.

Evaluation of the restorative effect of ozone and chitosan-hyaluronic acid with and without mesenchymal stem cells on wound healing in rats

This study evaluated the effect of ozone, chitosan-hyaluronic (Cs-HA) acid and mesenchymal stem cells (MSCs) on wound healing in rats. A total of 64 rats were randomly divided into four groups: control, ozone, Cs-HA + ozone and Cs-HA + ozone + MSCs. A 5 mm full-thickness wound was created on the back of each rat. The wound area was measured macroscopically on days 3, 5, 9 and 14. Tissue sections were prepared for histopathological evaluation of inflammation, collagen arrangement, neovascularization and epithelial tissue rearrangement. Macroscopic assessment showed differences in wound area on days 5, 9 and 14. Histopathological examination showed that the Cs-HA + ozone + MSCs and Cs-HA + ozone groups had significantly higher vascularization on day 3 compared to the ozone-treated and control groups. All treatment groups had significantly better collagen arrangement than the control group. On day 5, no significant difference was observed between different groups. On day 9, the inflammation level in the Cs-HA + ozone + MSCs group was significantly lower than in the other groups. All treatment groups had significantly better vascularization compared to the control group. On day 14, the rate of inflammation was significantly lower in the treatment groups than in the control group. Significantly higher collagen arrangement levels were observed in the Cs-HA + ozone and Cs-HA + ozone + MSCs groups compared to the control and ozone groups. All treatment groups had significantly better epithelial tissue rearrangement than the control group. Overall, the results of this study indicated that treatment with ozone, Cs-HA acid, Cs-HA and MSCs accelerated wound healing in rats. The effect of using Cs-HA acid with mesenchymal cells was better than the other types of treatment. Larger clinical trials are needed to assess these factors for improving chronic wound treatment.

Naked mole-rat hyaluronan

Naked mole rats (NMRs) are renowned for their exceptional longevity and remarkable maintenance of health throughout their lifetime. Their subterranean lifestyle has led to adaptations that have resulted in elevated levels of a very high molecular weight hyaluronan in their tissues. Hyaluronan, a glycosaminoglycan, is a key component of the extracellular matrix, which plays a critical role in maintaining tissue structure and regulating cell signaling pathways. This phenomenon in NMRs is attributed to a higher processing and production capacity by some of their hyaluronan synthases, along with lower degradation by certain hyaluronidases. Furthermore, this adaptation indirectly confers several advantages to NMRs, such as the preservation of skin elasticity and youthful appearance, accelerated wound healing, protection against oxidative stress, and resistance to conditions such as cancer and arthritis, largely attributable to CD44 signaling and other intricate mechanisms. Thus, the main objective of this study was to conduct a comprehensive study of the distinctive features of NMR hyaluronan, particularly emphasizing the currently known molecular mechanisms that contribute to its beneficial properties. Furthermore, this research delves into the potential applications of NMR hyaluronan in both cosmetic and therapeutic fields, as well as the challenges involved.

A clinical study of the local injection of a freshly manufactured 35 kDa hyaluronan fragment for treating chronic wounds

This study manufactured a 35 kDa hyaluronan fragment (HA35) by enzymatically degrading high-molecular-weight HA using hyaluronidase PH20 derived from bovine testis. The research then examined the therapeutic efficacy of locally administered, tissue-permeable HA35 in alleviating chronic wounds and their associated neuropathic pain. For 20 patients with nonhealing wounds and associated pain lasting over three months, 100 mg of HA35 was injected daily into the healthy skin surrounding the chronic wound for 10 days. Self-assessments before and after treatment indicated that HA35 significantly enhanced wound healing. This was evidenced by the formation of fresh granulation tissue on the wounds (p < 0.0001); reduced darkness, redness, dryness, and damage in the skin surrounding the wounds (p < 0.0001), and a decrease in wound size (p < 0.001). Remarkably, HA35 injections alleviated pain associated with chronic wounds within 24 hours (p < 0.0001). It can be concluded that the low-molecular-weight hyaluronan fragment HA35 potentially enhances the immune response and angiogenesis during wound healing.

Macrofungal Mediated Biosynthesis of Silver Nanoparticles and Evaluation of Its Antibacterial and Wound-Healing Efficacy

Recently, the utilization of biological agents in the green synthesis of nanoparticles has been given interest. In this study, silver nanoparticles were synthesized from an aqueous extract of macrofungus (mushroom), namely Phellinus adamantinus, in a dark room using 20 µL of silver nitrate. Biosynthesized silver nanoparticles were confirmed by analyzing them using a UV-Vis (ultraviolet-visible) spectrophotometer. The synthesized silver nanoparticles were optimized at different pH and temperatures with various dosages of AgNO3 (silver nitrate) and fungal extracts. The synthesized AgNPs (silver nanoparticles) were characterized using TEM (transmission electron microscopy) and EDX (energy-dispersive X-ray) analyses, which confirmed the presence of silver nanoparticles. The size of the nanosilver particles was found to be 50 nm with higher stability. The mycosynthesized AgNPs showed effective antibacterial activity against strains of Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (E. coli and Pseudomonas aeruginosa) bacteria. The minimum inhibitory concentration (MIC) was found to be 3.125 μg/mL by MIC assay. The MTT assay (3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyl-2H-tetrazolium bromide) was performed to study cytotoxicity, and reduced cell viability was recorded at 100 μg/mL. Silver-Polygalacturonic acid-Polyvinyl alcohol ((Ag-PGA)-PVA) nanofiber was prepared using the electrospinning method. The in vitro wound scratch assay was demonstrated to study the wound-healing efficacy of the prepared nanofiber. The wound-healing efficacy of the AgNP-incorporated nanofiber was found to be 20% after 24 h. This study will lay a platform to establish a unique route to the development of a novel nanobiomaterial and its application in antibacterial and wound-healing therapy.

A focused review on hyaluronic acid contained nanofiber formulations for diabetic wound healing

The significant clinical challenge presented by diabetic wounds is due to their impaired healing process and increased risk of complications. It is estimated that a foot ulcer will develop at some point in the lives of 15-25 % of diabetic patients. Serious complications, including infection and amputation, are often led to by these wounds. In the field of tissue engineering and regenerative medicine, nanofiber-based wound dressings have emerged in recent years as promising therapeutic strategies for diabetic wound healing. Hyaluronic acid (HA), among various nanofiber materials, has gained considerable attention due to its unique properties, including biocompatibility, biodegradability, and excellent moisture retention capacity. By promoting skin hydration and controlling inflammation, a crucial role in wound healing is played by HA. Wounds are also helped to heal faster by HA through the regulation of inflammation levels and signaling the body to build more blood vessels in the damaged area. Great potential in various applications, including wound healing, has been shown by the development and use of nanofiber formulations in medicine. However, challenges and limitations associated with nanofibers in medicine exist, such as reproducibility, proper characterization, and biological evaluation. By providing a biomimetic environment that enhances re-epithelialization and facilitates the delivery of active substances, nanofibers promote wound healing. In accelerating wound healing, promising results have been shown by HA-contained nanofiber formulations in diabetic wounds. Key strategies employed by these formulations include revascularization, modulation of the inflammation microenvironment, delivery of active substances, photothermal nanofibers, and nanoparticle-loaded fabrics. Particularly crucial is revascularization as it restores blood flow to the wound area, promoting healing. Wound healing can also be enhanced by modulating the inflammation microenvironment through controlling inflammation levels. Future perspectives in this field involve addressing the current challenges and limitations of nanofiber technology and further optimizing HA-contained nanofiber formulations for improved efficacy in diabetic wound healing. This includes exploring new fabrication techniques, enhancing the biocompatibility and biodegradability of nanofibers, and developing multifunctional nanofibers for targeted drug delivery. Not only does writing a review in the field of nanofiber-based wound dressings, particularly those containing hyaluronic acid, allow us to consolidate our current knowledge and understanding but also broadens our horizons. An opportunity is provided to delve deeper into the intricacies of this innovative therapeutic strategy, explore its potential and limitations, and envision future directions. By doing so, a contribution can be made to the ongoing advancements in tissue engineering and regenerative medicine, ultimately improving the quality of life for patients with diabetic wounds.

Marine Biomaterials: Hyaluronan

The marine-derived hyaluronic acid and other natural biopolymers offer exciting possibilities in the field of biomaterials, providing sustainable and biocompatible alternatives to synthetic materials. Their unique properties and abundance in marine sources make them valuable resources for various biomedical and industrial applications. Due to high biocompatible features and participation in biological processes related to tissue healing, hyaluronic acid has become widely used in tissue engineering applications, especially in the wound healing process. The present review enlightens marine hyaluronan biomaterial providing its sources, extraction process, structures, chemical modifications, biological properties, and biocidal applications, especially for wound healing/dressing purposes. Meanwhile, we point out the future development of wound healing/dressing based on hyaluronan and its composites and potential challenges.

Structures, Properties, and Bioengineering Applications of Alginates and Hyaluronic Acid

In recent years, polymeric materials have been used in a wide range of applications in a variety of fields. In particular, in the field of bioengineering, the use of natural biomaterials offers a possible new avenue for the development of products with better biocompatibility, biodegradability, and non-toxicity. This paper reviews the structural and physicochemical properties of alginate and hyaluronic acid, as well as the applications of the modified cross-linked derivatives in tissue engineering and drug delivery. This paper summarizes the application of alginate and hyaluronic acid in bone tissue engineering, wound dressings, and drug carriers. We provide some ideas on how to replace or combine alginate-based composites with hyaluronic-acid-based composites in tissue engineering and drug delivery to achieve better eco-economic value.

Self-esterified hyaluronan hydrogels: Advancements in the production with positive implications in tissue healing

Hyaluronan-(HA) short half-life in vivo limits its benefits in tissue repair. Self-esterified-HA is of great interest because it progressively releases HA, promoting tissue-regeneration longer than the unmodified-polymer. Here, the 1-ethyl-3-(3-diethylaminopropyl)carbodiimide(EDC)-hydroxybenzotriazole(HOBt) carboxyl-activating-system was evaluated for self-esterifying HA in the solid state. The aim was to propose an alternative to the time-consuming, conventional reaction of quaternary-ammonium-salts of HA with hydrophobic activating-systems in organic media, and to the EDC-mediated reaction, limited by by-product formation. Additionally, we aimed to obtain derivatives releasing defined molecular-weight(MW)-HA that would be valuable for tissue renewal. A 250 kDa-HA(powder/sponge) was reacted with increasing EDC/HOBt amounts. HA-modification was investigated through Size-Exclusion-Chromatography-Triple-Detector-Array-analyses, FT-IR/¹H NMR and the products(XHAs) extensively characterized. Compared to conventional protocols, the set procedure is more efficient, avoids side-reactions, allows for an easier processing to diverse clinically-usable 3D-forms, leads to products gradually releasing HA under physiological conditions with the possibility to tune the MW of the biopolymer-released. Finally, the XHAs exhibit sound stability to Bovine-Testicular-Hyaluronidase, hydration/mechanical properties suitable for wound-dressings, with improvements over available matrices, and prompt in vitro wound-regeneration, comparably to linear-HA. To the best of our knowledge, the procedure is the first valid alternative to conventional protocols for HA self-esterification with advances in the process itself and in product performance.

Stimuli-Responsive Polysaccharide Hydrogels and Their Composites for Wound Healing Applications

There is a growing concern about wound care, since traditional dressings such as bandages and sutures can no longer meet existing needs. To address the demanding requirements, naturally occurring polymers have been extensively exploited for use in modern wound management. Polysaccharides, being the most abundant biopolymers, have some distinct characteristics, including biocompatibility and biodegradability, which render them ideal candidates for wound healing applications. Combining them with inorganic and organic moieties can produce effective multifunctional composites with the desired mechanical properties, high wound healing efficiencies and excellent antibacterial behavior. Recent research endeavors focus on the development of stimuli-responsive polysaccharide composites for biomedical applications. Polysaccharide composites, being sensitive to the local environment, such as changes of the solution temperature, pH, etc., can sense and react to the wound conditions, thus promoting an effective interaction with the wound. This review highlights the recent advances in stimuli-responsive polysaccharide hydrogels and their composites for use in wound healing applications. The synthetic approaches, physical, chemical, and biochemical properties as well as their function in wound healing will be discussed.

Hyaluronic acid-based nanofibers: Electrospun synthesis and their medical applications; recent developments and future perspective

Hyaluronan is a biodegradable, biopolymer that represents a major part of the extracellular matrix and has the potential to be fabricated in a fibrous form conjugated with other polymers via electrospinning. Unique physicochemical features such as viscoelasticity, conductivity, and biological activity mainly affected by molecular weight attracted the attention of biomedical researchers to utilize hyaluronan for designing novel HA-based nano-devices. Particularly HA-based nanofibers get focused on a diverse range of applications in medical like tissue implants for regeneration of damaged tissue or organ repair, wound dressings, and drug delivery carriers to treat various disorders. Currently, electrospinning represents an effective available method for designing highly porous, 3D, HA-based nanofibers with features similar to that of the extra-cellular matrix making them a promising candidate for designing advanced regenerative medicines. This review highlights the structural and physicochemical features of HA, recently cited protocols in literature for HA production via microbial fermentation with particular focus on electrospun fabrication of HA-based nanofibers and parameters affecting its synthesis, current progress in medical applications of these electrospun HA-based nanofibers, their limitations and future perspective about the potential of these HA-based nanofibers in medical field.

A Comprehensive Review of the Application of Nanoparticles in Diabetic Wound Healing: Therapeutic Potential and Future Perspectives

Diabetic wounds are one of the most challenging public health issues of the 21st century due to their inadequate vascular supply, bacterial infections, high levels of oxidative stress, and abnormalities in antioxidant defenses, whereas there is no effective treatment for diabetic wounds. Due to the distinct properties of nanoparticles, such as their small particle size, elevated cellular uptake, low cytotoxicity, antibacterial activity, good biocompatibility, and biodegradability. The application of nanoparticles has been widely used in the treatment of diabetic wound healing due to their superior anti-inflammatory, antibacterial, and antioxidant activities. These nanoparticles can also be loaded with various agents, such as organic molecules (eg, exosomes, small molecule compounds, etc.), inorganic molecules (metals, nonmetals, etc.), or complexed with various biomaterials, such as smart hydrogels (HG), chitosan (CS), and hyaluronic acid (HA), to augment their therapeutic potential in diabetic wounds. This paper reviews the therapeutic potential and future perspective of nanoparticles in the treatment of diabetic wounds. Together, nanoparticles represent a promising strategy in the treatment of diabetic wound healing. The future direction may be to develop novel nanoparticles with multiple effects that not only act in wound healing at all stages of diabetes but also provide a stable physiological environment throughout the wound-healing process.

Polysaccharides, as biological macromolecule-based scaffolding biomaterials in cornea tissue engineering: A review

Corneal-related diseases and injuries are the leading causes of vision loss, estimated to affect over 10 million people worldwide. Currently, cadaveric corneal grafts are considered the gold standard of treatment to restore cornea-related vision. However, this treatment modality faces different challenges such as donor shortage and graft failure. Therefore, the need for alternative solutions continues to grow. Tissue engineering has dramatically progressed to produce artificial cornea implants in order to repair, regenerate, or replace the damaged cornea. In this regard, a variety of polysaccharides such as cellulose, chitosan, alginate, agarose, and hyaluronic acid have been widely explored as scaffolding biomaterials for the production of tissue-engineered cornea. These polymers are known for their excellent biocompatibility, versatile properties, and processability. Recent progress and future perspectives of polysaccharide-based biomaterials in cornea tissue engineering is reviewed here.

Hyaluronic Acid-Based Wound Dressing with Antimicrobial Properties for Wound Healing Application

Wound healing is a naturally occurring process that can be aided by a wound dressing properly designed to assure an efficient healing process. An infection caused by several microorganisms could interfere with this process, delaying or even impairing wound healing. Hyaluronic acid (HA), a main constituent of the extracellular matrix (ECM) of a vertebrate’s connective tissue, represents a promising biomaterial for wound dressing thanks to its intrinsic biocompatibility, hydrophilicity and bacteriostatic properties. In this review, different and recent types of HA-based wound dressings endowed with intrinsic antimicrobial properties or co-adjuvated by antimicrobial natural or synthetic agents are highlighted.

Further structural characterization of ovine forestomach matrix and multi-layered extracellular matrix composites for soft tissue repair

Decellularized extracellular matrix (dECM)-based biomaterials are of great clinical utility in soft tissue repair applications due to their regenerative properties. Multi-layered dECM devices have been developed for clinical indications where additional thickness and biomechanical performance are required. However, traditional approaches to the fabrication of multi-layered dECM devices introduce additional laminating materials or chemical modifications of the dECM that may impair the biological functionality of the material. Using an established dECM biomaterial, ovine forestomach matrix, a novel method for the fabrication of multi-layered dECM constructs has been developed, where layers are bonded via a physical interlocking process without the need for additional bonding materials or detrimental chemical modification of the dECM. The versatility of the interlocking process has been demonstrated by incorporating a layer of hyaluronic acid to create a composite material with additional biological functionality. Interlocked composite devices including hyaluronic acid showed improved in vitro bioactivity and moisture retention properties.

Gallocatechin‑silver nanoparticle impregnated cotton gauze patches enhance wound healing in diabetic rats by suppressing oxidative stress and inflammation via modulating the Nrf2/HO-1 and TLR4/NF-κB pathways

This study is designed to investigate the combination of gallocatechin (GC) and silver nanoparticles (AgNPs) for its wound healing ability in diabetic rats. Thirty male Sprague Dawley rats were randomly divided into 5 groups: 1. Normal control rats dressed with blank CGP1; 2. Diabetic rats dressed with blank CGP1; 3. Diabetic rats dressed with 13.06μM of GC; 4. Diabetic rats dressed with 26.12 μM of GC; 5. Diabetic rats dressed with 0.1% silver sulfadiazine patches. GC-AgNPs-CGP dressed diabetic rats showed significant FBG reduction, prevented the body weight losses and reduced the oxidative stress by lowering MDA content and elevated antioxidant enzymes such as SOD, CAT and GPx in wound healing skin of diabetic rats when compared to normal CGP. Besides, mRNA expression of Nrf2, Nqo-1, and Ho-1 was upregulated with downregulated expression of Keap-1 mRNA, which is supported by immunohistochemistry. Furthermore, GC-AgNPs-CGP dressing increased growth factors such as VEGF, EGF, TGF-β, and FGF-2 while decreasing MMP-2 in the skin of diabetic wound rats. In vitro permeation study demonstrated rapid GC release and permeation with a flux of 0.061 and 0.143 mg/sq.cm/h. In conclusion, the results indicated that GC-AgNPs-CGP dressing on diabetic wound rats modulated oxidative stress and inflammation with elevated growth factors; increased collagen synthesis thereby significantly improved the wound healing and could be beneficial for the management of diabetic wounds.

Preparation and characterization of succinyl chitosan and succinyl chitosan nanoparticle film: In vitro and in vivo evaluation of wound healing activity

Development of novel wound dressing materials having the ability to prevent bacterial infections and capable of accelerating the tissue regeneration process is utmost important, since the wounds in patients can cause severe health issues. In the present work, we synthesized novel N-succinyl chitosan nanoparticles (N-SuC NPs) films and tested their antimicrobial, cytotoxicity, and in vitro and in vivo wound healing activity. N-SuC NPs were synthesized by ionic gelation method, and subsequently N-SuC NPs films were prepared by solution casting method using synthesized N-SuC NPs. The prepared N-SuC NPs films showed significant antimicrobial activity against Escherichia coli and Staphylococcus aureus with a minimum inhibitory concentration of 6 mg/mL and <8 mg/mL, respectively. The biocompatibility and the in vitro wound healing activity of N-SuC NPs films were analyzed using human dermal fibroblast (HDF) cells. In vivo cutaneous wound healing of the N-SuC NPs film was investigated using the Wister rat model, and the studies showed that the N-SuC NPs film significantly accelerated the wound healing process by inducing more blood vessels formation and tissue granulation. The experimental results showed that synthesized N-SuC NPs film had excellent antimicrobial, cytotoxicity and wound healing activity, indicating that it could be used in biomedical applications.

Antimicrobial electrospun nanofiber mats of NaOH-hydrolyzed chitosan (HCS)/PVP/PVA incorporated with in-situ synthesized AgNPs: Fabrication, characterization, and antibacterial activity

This work aims to improve the electrospinability and antibacterial activity of chitosan (CS) - based nanofibers. Three approaches consisting of reducing molecular weight of CS by NaOH hydrolysis (HCS), blending with two carrying polymers (polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA)) and incorporating with in-situ synthesized silver nanoparticles (AgNPs) were integrated simultaneously for the first time to fabricate the HCS-AgNPs/PVP/PVA multicomponent nanofibers. The electrospinning parameters were optimized to obtain the smooth and uniform nanofibers without beads of both HCS/PVP/PVA and HCS-AgNPs/PVP/PVA systems. The presence of in-situ AgNPs in the multicomponent blends gives the better electrospinning performance and the lowest fiber diameter of 139 nm. In addition, the thermal properties, thermal stability and crystallinity index of both nanofibers also increased with increasing HCS or HCS-AgNPs fractions. Finally, the best antibacterial activity of HCS/PVP/PVA and HCS-AgNPs/PVP/PVA nanofibers against E. coli was found to be 74.4% and 99.9%, respectively. The significant enhancement in bactericidal activity of HCS-AgNPs/PVP/PVA nanofibers against E. coli is due to the synergistic properties of HCS/PVP/PVA blends and AgNPs. Both nanofiber mats displayed the excellent structural stability in moisture environment for at least 7 days. Therefore, the HCS-AgNPs/PVP/PVA nanofibers could be a potential material for applying in the medical purpose.

Improved wound healing of diabetic foot ulcers using human placenta-derived mesenchymal stem cells in gelatin electrospun nanofibrous scaffolds plus a platelet-rich plasma gel: A randomized clinical trial

AIM

The effectiveness of nanofibers containing human placenta-derived mesenchymal stem cells (hPDMSCs) plus platelet-rich plasma (PRP) for healing of diabetic foot ulcers (DFUs) was investigated.

METHODS

hPDMSCs were isolated from human donor placentas, and cultured in electrospun gelatin nanofibrous scaffolds (GNS). Twenty-eight patients with DFUs were randomized into three groups in a 12-week trial: (A) Treated with hPDMSCs; (B) Treated with hPDMSCs after coating the ulcer with PRP gel; (C) Control group received standard wound care. Wound area and pain freewalkingdistance were measured every 2 weeks.

RESULTS

Flow cytometry showed the expression of mesenchymal markers. SEM images and DAPI staining indicated significantly higher levels of hPDMSC proliferation on GNS after 3 and 7 days of culture. The MTS assay showed a significant increase in proliferation on GNS, compared to controls. Wound size reduction was 66% in group A, 71% in group B, and 36% in control group C. A significant difference in wound closure and pain-free walking distance was observed between groups A and B, compared to control group C (p < 0.05), but no difference between groups A and B. Biopsy of the implanted tissue showed the development of new capillary formation in groups A and B.

CONCLUSION

Implantation of hPDMSCs in GNS accelerated wound healing and improved clinical parameters in DFU patients.

Hyaluronic acid nanofiber mats loaded with antimicrobial peptide towards wound dressing applications

Chronic wounds are highly susceptible to bacterial infections. Previously, we loaded a natural antimicrobial peptide of low cost and high safety, ε-polylysine (EPL), into the electrospun nanofiber mat of starch. The mat showed comparable antibacterial activity but markedly better biocompatibility than the commercial silver-containing dressing. To further optimize material property, in this paper, we use hyaluronic acid (HA) to replace starch. Results show that EPL-loaded HA nanofiber mats (OHA-EPL) have suitable water vapor permeability, good biocompatibility and broad-spectrum antibacterial property similar to that of EPL-loaded starch nanofiber mat (Starch-EPL). Differently, the content of EPL in OHA-EPL nanofiber mats increases from 19.2% to 27.9%, the tensile strength rises from 0.3 MPa to 0.6 MPa, the elongation grows from 62.0% to 130.0%, and the fiber degradation and EPL release accelerates. In addition, OHA-EPL can absorb up to 26.3-times exudate, which is much higher than Starch-EPL (15.1 times). Combined with the excellent biological activity of HA, OHA-EPL may produce better therapeutic effects than Starch-EPL.

Preparation, optimization, and characterization of chitosan-sepiolite nanocomposite films for wound healing

In this study, a series of chitosan-sepiolite (CS-SEP) nanocomposites films were prepared by using a conventional solution casting method. The effect of sepiolite on physicochemical and biological properties of the prepared nanocomposite films was studied by various techniques such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and x-ray diffraction (XRD) to name a few. In WCA measurements, the decrease of contact angle from 78.51° (CS) to 71.29° (CS7SEP3) reaffirms the water holding nature of sepiolite, which enables to create moist environment essentially required for wound healing. Further, addition of sepiolite tremendously increased WVTR, folding endurance, porosity, and blood clotting ability of the prepared nanocomposites. Furthermore, CS-SEP nanocomposite films exhibit better antibacterial activity than that of chitosan against gram positive (B. subtilis) and gram negative bacteria (E. coli). Moreover, the percentage of hemolysis and degradation study indicated that the prepared nanocomposite films were non-hemolytic in nature and decomposed nearly 40% in four weeks. In addition, cytotoxicity assay showed that the prepared nanocomposite film i.e. CS7SEP3 exhibited better cell viability and cell proliferation rate against L929 mouse fibroblast cells as compared to CS and hence, the prepared nanocomposite film can be used as a promising candidate for wound management.

Malnutrition delayed wound healing after tooth extraction by HMGB1-related prolonged inflammation

Malnutrition causes prolonged inflammation, resulting in delayed wound healing. High mobility group box-1 (HMGB1) is a damage-associated molecular pattern that is present in the nuclei of macrophages and is secreted into the extracellular milieu in response to stimuli. It stimulates the production of interleukin-1β (IL-1β) through the receptors for advanced glycation end products (RAGE), inducing an inflammatory response, which is an essential response to initiate wound healing. We hypothesized that malnutrition may interfere with this cascade, causing abnormal inflammation and ultimately delaying wound healing. We used tooth-extracted mice with malnutrition fed with low-casein diet for two weeks. On days 3 and 7 after tooth extraction, the wound tissue was histologically observed and analyzed for several factors in the inflammation-regeneration lineage, including IL-1β, mesenchymal stem cells, myeloperoxidase activity, HMGB1, macrophage polarization, and adenosine 5-triphosphate (ATP). On day 7, delayed wound healing was observed with the following findings under malnutrition conditions: decreased mRNA expression of genes for regeneration and mesenchymal stem cell (MSC) accumulation, an obvious increase in myeloperoxidase and IL-1β mRNA expression, an increase in HMGB1 levels, and an increase in ATP concentration in tissues with elevated proportion of M2 macrophages. These results suggest that the significantly increased secretion of HMGB1 associated with the upregulated production of ATP and IL-1β secretion via the RAGE pathway may interfere with the resolution of inflammation and wound healing under the state of malnutrition.

Therapeutic potential of Moringa oleifera seed polysaccharide embedded silver nanoparticles in wound healing

Wound healing is a complicated process that influences patient's life quality. Plant-based polysaccharide has recently gained interest in its use in wound dressing materials because of its biological compatibility, natural abundance, and ideal physiochemical properties. The present study reveals the potential of polysaccharide isolated from Moringa oleifera seed (MOS-PS) and its nanocomposite with silver (MOS-PS-AgNPs) as alternative materials for wound dressing. First, MOS-PS was isolated and structurally characterized by TLC, HPLC, FTIR, NMR, and GPC analyses. A green and simple method was used to synthesize AgNPs using MOS-PS as a stabilizing and reducing agent. The size, morphology, and structure of the MOS-PS-AgNPs were characterized by UV-Vis spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and zeta potential analysis. The results showed that the MOS-PS-AgNPs were spherically shaped, having no cytotoxicity toward mouse fibroblasts cells and promoting their in-vitro migration. Moreover, the MOS-PS-AgNPs displayed strong anti-microbial activity against wound infectious pathogenic bacteria. Finally, the MOS-PS-AgNPs were used for dressing animal wounds and its preliminary mechanism was studied by RT-PCR and histological analysis. The results showed that the MOS-PS-AgNPs can promote wound contraction and internal tissue growth well. Overall, our results indicated that the MOS-PS-AgNPs might be an excellent candidate for use as an optimal wound dressing material.

Nanotechnology Approaches in Chronic Wound Healing

Significance: The incidence of chronic wounds is increasing due to our aging population and the augment of people afflicted with diabetes. With the extended knowledge on the biological mechanisms underlying these diseases, there is a novel influx of medical technologies into the conventional wound care market. Recent Advances: Several nanotechnologies have been developed demonstrating unique characteristics that address specific problems related to wound repair mechanisms. In this review, we focus on the most recently developed nanotechnology-based therapeutic agents and evaluate the efficacy of each treatment in in vivo diabetic models of chronic wound healing. Critical Issues: Despite the development of potential biomaterials and nanotechnology-based applications for wound healing, this scientific knowledge is not translated into an increase of commercially available wound healing products containing nanomaterials. Future Directions: Further studies are critical to provide insights into how scientific evidences from nanotechnology-based therapies can be applied in the clinical setting.

Antibacterial and wound healing-promoting effect of sponge-like chitosan-loaded silver nanoparticles biosynthesized by iturin

Silver nanoparticles (AgNPs) are widely used in wound dressing, but are limited in the application due to its high toxicity at effective concentrations. iturin-AgNPs was previously found to have much higher antibacterial activity at lower AgNPs content than the commercial AgNPs. To verify its potential application in the promotion of wound healing, a chitosan (CS) composite sponge dressing-loaded iturin-AgNPs was developed and evaluated for their antibacterial activity in vitro and used for wound healing in vivo. As results, the synthesized CS dressing had high porosity and water absorption. As expected, the antibacterial activity of CS dressing was significantly promoted by the incorporation of iturin-AgNPs. The CS dressing-loaded iturin-AgNPs showed more effective inhibition of bacterial infection and promotion of wound healing processing and quality than the commercial wound dressing loaded AgNPs in vivo. The mechanisms for the promotion of wound healing by the CS dressing-loaded iturin-AgNPs were found as the enhancement of re-epithelialization and collagen formation, as well as the increased antibacerial activity. No toxicity was found to all organs of mice. The study developed an efficient way to enhance the antibacterial activity of CS dressing loaded AgNPs at low toxicity, which has great potential in wound care application.

Polyphenols: A Promising Avenue in Therapeutic Solutions for Wound Care

In chronic wounds, the regeneration process is compromised, which brings complexity to the therapeutic approaches that need to be adopted, while representing an enormous loss in the patients’ quality of life with consequent economical costs. Chronic wounds are highly prone to infection, which can ultimately lead to septicemia and morbidity. Classic therapies are increasing antibiotic resistance, which is becoming a critical problem beyond complex wounds. Therefore, it is essential to study new antimicrobial polymeric systems and compounds that can be effective alternatives to reduce infection, even at lower concentrations. The biological potential of polyphenols allows them to be an efficient alternative to commercial antibiotics, responding to the need to find new options for chronic wound care. Nonetheless, phenolic compounds may have some drawbacks when targeting wound applications, such as low stability and consequent decreased biological performance at the wound site. To overcome these limitations, polymeric-based systems have been developed as carriers of polyphenols for wound healing, improving its stability, controlling the release kinetics, and therefore increasing the performance and effectiveness. This review aims to highlight possible smart and bio-based wound dressings, providing an overview of the biological potential of polyphenolic agents as natural antimicrobial agents and strategies to stabilize and deliver them in the treatment of complex wounds. Polymer-based particulate systems are highlighted here due to their impact as carriers to increase polyphenols bioavailability at the wound site in different types of formulations.

Preparation of 6-carboxyl chitin and its effects on cell proliferation in vitro

This study concerns the performance evaluation of 6-carboxyl chitin for its wound healing application. 6-Carboxyl chitins were prepared by the oxidation of chitin at C-6 with NaClO/TEMPO/NaBr after α-chitin was pretreated in NaOH/urea solution. The products with different molecular weights were obtained by changing reaction conditions. They all were completely oxidized at C-6 and N-acetylated at C-2 according to FT-IR and NMR results. 6-Carboxyl chitins could stimulate significantly the proliferation of human skin fibroblasts (HSF) and human keratinocytes (HaCaT), and the bioactivities were concentration and Mws dependent. Within the scope of the study, 10-40 kDa of Mws and 10-100 μg/mL of concentrations were most suitable for the HSF proliferation, but the proliferation of HaCaT increased with decreasing the concentration and Mw. In addition, 6-carboxyl chitins could also induce macrophages and fibroblasts to secrete growth factors. Therefore, 6-carboxyl chitins could be expected to be an active ingredient for wound healing.

Hyaluronic acid with antioxidants improve wound healing in rats

Hyaluronic acid (HA) is found in connective tissue and participates in wound healing. We investigated the efficacy of a HA gel (2% hyaluronic acid; 1% antioxidants, coenzyme Q10 and vitamin E; and 5% benzocaine) on healing of palatal wounds in rats. We established two groups of rats: a control group treated with vehicle and an HA group treated with HA gel. The control group was divided into five subgroups and the HA group was divided into four subgroups according to the day on which animals were sacrificed. Wounds were created by elevating 5 mm diameter full thickness flaps. Healed and unhealed wound areas were measured using photographs. Transforming growth factor (TGF)-β, insulin-like growth factor (IGF), and collagen I and III expressions were determined using immunohistochemistry. The number of fibroblasts increased and inflammatory cells decreased from day 0 to 21 in both groups. The HA group exhibited more fibroblasts by day 7 compared to controls; (TGF)-β and IGF levels were similar between HA and control groups. HA groups exhibited fewer inflammatory cells than controls on days 3 and 7. We found significant differences in TGF-β and IGF levels among HA groups between days 3 and 21, and among control groups between days 0 and 21. Collagen I and III levels were greater for the day 3 HA group compared to controls. We observed improved wound healing in HA treated rats within 7 days.

Manufacture of pH- and HAase-responsive hydrogels with on-demand and continuous antibacterial activity for full-thickness wound healing

A kind of "intelligent" antibacterial dressing-A-HA/HA-ADH/SS hydrogel was in situ formed quickly via dynamic covalent bonds cross-linking between aldehyde hyaluronic acid (A-HA), adipic acid dihydrazide graft hyaluronic acid (HA-ADH) and sisomicin sulfate (SS). FT-IR, SEM and rheological results displayed that the hydrogels were successfully prepared. The hydrogels had good optical transmittance, injectability, self-healing ability, cytocompatibility, antioxidant activity and hemostatic performance which were beneficial to observe the wound healing condition and provide a good healing environment for wounds. In addition, the hydrogels showed a pH- and HAase- dependent degradability, which allowed them to release more SS at infected wound and then exert on-demand and sustained antibacterial effect against S. aureus and E. coli. The results of wound healing and histological examination revealed that these hydrogels have a good therapeutic effect in the full-thickness mouse skin defect wound. Thus, the hydrogels are expected to be used as potential wound dressings to improve wound healing.

The Effects of High Molecular Weight Hyaluronic Acid Eye Drop Application in Environmental Dry Eye Stress Model Mice

Hyaluronic acid (HA) ophthalmic solution is widely used in dry eye treatment worldwide. However, there are no reports comparing the dry eye treatment effects of high molecular weight HA with low molecular weight HA. Sixty eight-week-old C57BL/6 mice were assigned to the following 6 groups and exposed to environmental dry eye stress (EDES) that mimics office work environment: 1) 0.1% low molecular weight HA (LMWHA) eye drops, 2) 0.3% LMWHA eye drops, 3) 3% diquafosol sodium (DQ) eye drops, 4) 0.15% high molecular weight HA (HMWHA) eye drops, 5) no treatment with exposure to EDES (EDES+/Treatment-), and 6) no treatment without exposure to EDES (EDES-/Treatment-). After EDES, the HMWHA group had significantly longer break-up time (BUT) than the 0.1%, 0.3% LMWHA groups and the DQ group. After EDES, the HMWHA group had significantly lower lissamine green staining scores than the LMWHA and DQ groups. Subepithelial presumed dendritic cell density in the HMWHA group was significantly lower than the EDES+/Treatment- group. After EDES exposure, Conjunctival Muc5AC mRNA expression in the HMWHA group was significantly higher than the 0.1 and 0.3% LMWHA groups. Ophthalmic HMWHA solution may have a better dry eye treatment effect than LMWHA or DQ solution, owing to its anti-inflammatory effect.

Chitosan-glucan complex hollow fibers reinforced collagen wound dressing embedded with aloe vera. II. Multifunctional properties to promote cutaneous wound healing

This study presents an innovative multifunctional system in fabricating new functional wound dressing (FWD) products that could be used for skin regeneration, especially in cases of infected chronic wounds and ulcers. The innovation is based on the extraction, characterization, and application of collagen (CO)/chitosan-glucan complex hollow fibers (CSGC)/aloe vera (AV) as a novel FWS. For the first time, specific hollow fibers were extracted with controlled inner (500-900 nm)/outer (2-3 µm) diameters from mycelium of Schizophyllum commune. Further on, research and evaluation of morphology, hydrolytic stability, and swelling characteristics of CO/CSGC@AV were carried out. The obtained FWS showed high hydrolytic stability with enhanced swelling characteristics compared to native collagen. The hemostatic effect of FWS increased significantly in the presence of CSGC, compared to native CO and displayed excellent biocompatibility which was tested by using normal human dermal fibroblast (NHDF). The FWS showed high antibacterial activity against different types of bacteria (positive/negative grams). From in vivo measurements, the novel FWS increased the percentage of wound closure after one week of treatment. All these results imply that the new CO/CSGC@AV-FWD has the potential for clinical skin regeneration and applying for controlled drug release.

Soil Application of Nano Silica on Maize Yield and Its Insecticidal Activity Against Some Stored Insects After the Post-Harvest

Maize is considered one of the most imperative cereal crops worldwide. In this work, high throughput silica nanoparticles (SiO2-NPs) were prepared via the sol–gel technique. SiO2-NPs were attained in a powder form followed by full analysis using the advanced tools (UV-vis, HR-TEM, SEM, XRD and zeta potential). To this end, SiO2-NPs were applied as both nanofertilizer and pesticide against four common pests that infect the stored maize and cause severe damage to crops. As for nanofertilizers, the response of maize hybrid to mineral NPK, “Nitrogen (N), Phosphorus (P), and Potassium (K)” (0% = untreated, 50% of recommended dose and 100%), with different combinations of SiO2-NPs; (0, 2.5, 5, 10 g/kg soil) was evaluated. Afterward, post-harvest, grains were stored and fumigated with different concentrations of SiO2-NPs (0.0031, 0.0063. 0.25, 0.5, 1.0, 2.0, 2.5, 5, 10 g/kg) in order to identify LC50 and mortality % of four common insects, namely Sitophilus oryzae, Rhizopertha dominica, Tribolium castaneum, and Orizaephilus surinamenisis. The results revealed that, using the recommended dose of 100%, mineral NPK showed the greatest mean values of plant height, chlorophyll content, yield, its components, and protein (%). By feeding the soil with SiO2-NPs up to 10 g/kg, the best growth and yield enhancement of maize crop is noticed. Mineral NPK interacted with SiO2-NPs, whereas the application of mineral NPK at the rate of 50% with 10 g/kg SiO2-NPs, increased the highest mean values of agronomic characters. Therefore, SiO2-NPs can be applied as a growth promoter, and in the meantime, as strong unconventional pesticides for crops during storage, with a very small and safe dose.

Soil Application of Nano Silica on Maize Yield and Its Insecticidal Activity Against Some Stored Insects After the Post-Harvest

Maize is considered one of the most imperative cereal crops worldwide. In this work, high throughput silica nanoparticles (SiO₂-NPs) were prepared via the sol-gel technique. SiO₂-NPs were attained in a powder form followed by full analysis using the advanced tools (UV-vis, HR-TEM, SEM, XRD and zeta potential). To this end, SiO₂-NPs were applied as both nanofertilizer and pesticide against four common pests that infect the stored maize and cause severe damage to crops. As for nanofertilizers, the response of maize hybrid to mineral NPK, "Nitrogen (N), Phosphorus (P), and Potassium (K)" (0% = untreated, 50% of recommended dose and 100%), with different combinations of SiO₂-NPs; (0, 2.5, 5, 10 g/kg soil) was evaluated. Afterward, post-harvest, grains were stored and fumigated with different concentrations of SiO₂-NPs (0.0031, 0.0063. 0.25, 0.5, 1.0, 2.0, 2.5, 5, 10 g/kg) in order to identify LC₅₀ and mortality % of four common insects, namely Sitophilus oryzae, Rhizopertha dominica, Tribolium castaneum, and Orizaephilus surinamenisis. The results revealed that, using the recommended dose of 100%, mineral NPK showed the greatest mean values of plant height, chlorophyll content, yield, its components, and protein (%). By feeding the soil with SiO₂-NPs up to 10 g/kg, the best growth and yield enhancement of maize crop is noticed. Mineral NPK interacted with SiO₂-NPs, whereas the application of mineral NPK at the rate of 50% with 10 g/kg SiO₂-NPs, increased the highest mean values of agronomic characters. Therefore, SiO₂-NPs can be applied as a growth promoter, and in the meantime, as strong unconventional pesticides for crops during storage, with a very small and safe dose.

Wound healing of nanofiber comprising Polygalacturonic/Hyaluronic acid embedded silver nanoparticles: In-vitro and in-vivo studies

The current study is pertaining to develop a novel wound dressing, comprising natural biologically absorbable materials for wound healing In-vivo. Wound dressing is composed of Polygalacturonic acid, Hyaluronic acid embedded silver nanoparticles, which is further fabricated to form nanofibrous mat, using electrospinning. Silver nanoparticles was prepared using PGA. AgNPs in this formula will serve as an antioxidant and anti-inflammatory that protect cells from destructive effect of elevated ROS and accelerate wound healing. The physical performance and water contact angle for nanofiber was evaluated. The produced nanofiber was characterized by Fourier-transform infrared (FTIR), scanning electron microscopy and thermal analysis. Also, the embedded AgNPs was also characterized by UV-vis spectroscopy and TEM. The nanofiber mates embedded AgNPs was applied to the wounded site of albino rats in-vivo. Histopathological assessment for the wound was fully performed. Also, the antimicrobial activity for the fabricated wound dressing was evaluated against gram+ve and gram -ve bacteria.

Hyaluronic acid and metallic silver treatment of chronic wounds: healing rate and bacterial load control

OBJECTIVE

To confirm the safety and wound healing activity of a topical spray powder containing hyaluronic acid (HA) and metallic silver (Hyalosilver, Fidia Farmaceutici S.p.A., Italy), and investigate its effect on the control of bacterial load in vascular ulcers or category I-II pressure ulcers (PU).

METHODS

This is a single site, prospective, open label study involving patients with a vascular ulcer or category I-II PUs, presenting signs of critical bacterial colonisation. Patients with a wound size of ≤15cm² were enrolled. At baseline, a swab was taken of each wound for a semi-quantitative analysis of bacterial load and the first treatment of topical spray powder was applied. The patient was then requested to self-apply the medication once a day for 28 consecutive days and to return on days one, seven and 28 for clinical and microbiological assessments.

RESULTS

A total of 25 patients were enrolled in the study. Treatment with the topical spray powder enhanced the healing rate of chronic wounds in terms of a reduction of wound area as well as bacterial load (p<0.025) and the overall clinical status of wound (odour, exudate, erythema of periwound skin; p<0.017). Moreover, the spray powder increased overall patient perception of improvement in the wound (p<0.05).

CONCLUSION

The data demonstrated good safety and tolerability of the topical spray powder suggesting that the product is effective not only in reducing wound area, due to the presence of HA, but in keeping the bacterial colonisation under control.

Utilization of High throughput microcrystalline cellulose decorated silver nanoparticles as an eco-nematicide on root-knot nematodes

The present study aimed to evaluate the influence of high throughput microcrystalline cellulose embedded silver nanoparticles (Ag-NPs), as an alternative eco-nematicide on Root-knot nematode (Meliodogyne incognita), which deem the main reason toward the loss of more than 20% in crops worldwide. In this work, Ag-NPs was prepared in very high concentration. Ag-NPs prepared using such technique has many advantages such as: absence of organic or solvents, scaling up thru using high concentration of silver precursor and utilization of environmentally benign polymer; Microcrystalline Cellulose (MCC). At the beginning, the bulk Ag-NPs colloidal solution is diluted to 5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 80 and 100 ppm. Then, heavily galled roots of annual seed-propagated weed, Solanum nigrum L. family Solanaceae were selected to identify the Meloidogyne species and followed by treatment with the previously Ag-NPs concentrations. Results obtained after 24 h incubation, showed the highest mortality (M%) (40.36 ± 1.15%) which was achieved by means of 20 ppm of Ag-NPs compared with the highest concentration of Ag-NPs; 100 ppm (42.85 ± 3.51%). It was obviously noticed that, by increasing the concentration of Ag-NPs, M % decreased. On the other hand, after 48 h, 30 ppm Ag-NPs showed the highest M%; (52.82 ± 0.57%), while, after 72 h of treatments, the M% reached 95.53 ± 0.57% using 40 ppm Ag-NPs, then decreased to 66.67 ± 2.00% using 100 ppm Ag-NPs. All previous finding affirms the effectiveness of lower concentrations of Ag-NPs compared with the highest one, after 72 h. In conclusion, Ag-NPs could be successfully used as eco-nematicide for Root-knot nematodes; Meloidogyne incognita with a recommended dose of 20-40 ppm that is acquired higher M% and caused many aberrations during the different growth stages.

Biomimetic hydrogel for rapid and scar-free healing of skin wounds inspired by the healing process of oral mucosa

Inspired by the wound healing characteristics of the oral mucosa, a biomimetic hydrogel was prepared to realize the rapid and scar-free healing of skin wounds. Through monitoring the healing process of injured oral mucosa, we find out that the combination of high, rapid and sequential expression of some growth factors and the sterile-moist microenvironment are crucial for re-epithelialization and precise control of the inflammation process. On the base of our findings, a hydrogel loaded with several functional compounds was prepared to achieve a comprehensive simulation of the oral mucosal trauma microenvironment for skin wound healing. After 7 days treatment, the skin wound area of the treated group was only about 20% of that of the untreated group, and the proportion of collagen type III and type I in the treated group was much higher than that of the untreated group, suggesting lighter scar hyperplasia. The comprehensive treatment strategy of sequential expression of growth factors in combination with maintaining of a sterile and humid environment is expected to have great application prospect in the field of chronic trauma repair and cosmetic surgery. STATEMENT OF SIGNIFICANCE: Long healing time and scar hyperplasia during wound healing have been a serious problem in the past decades of wound healing research. Oral cavity wound healing occurs in an environment that sustains ongoing physical trauma and is rich in bacteria. Despite this, injuries to the mucosal surface often heal faster than cutaneous wounds and leave less noticeable scars. Therefore, in recent years, many scholars have begun to study the healing mechanism of oral mucosa, which supports a new inspiration for the study of skin wound repair: whether the injured skin can achieve a rapid scar-free healing effect similar to oral mucosa? Imitating the biological process of oral mucosa wound healing would be a promising therapeutic strategy in wound healing. Therefore, inspired by the wound healing characteristics of the oral mucosa, a biomimetic gel was prepared to realize the rapid and scar-free healing of skin wounds. Through monitoring the healing process of injured oral mucosa, the combination of high, rapid and sequential expression of some growth factors and sterile-moist microenvironment was crucial for re-epithelialization and precise control of the inflammation process. The comprehensive treatment strategy of sequential expression of growth factors in combination with maintance of a sterile and humid environment implies its potential use in the field of chronic trauma repair and cosmetic surgery.

A Low Molecular Weight Hyaluronic Acid Derivative Accelerates Excisional Wound Healing by Modulating Pro-Inflammation, Promoting Epithelialization and Neovascularization, and Remodeling Collagen

Recent knowledge of the cellular and molecular mechanisms underlying cutaneous wound healing has advanced the development of medical products. However, patients still suffer from the failure of current treatments, due to the complexity of healing process and thus novel therapeutic approaches are urgently needed. Previously, our laboratories produced a range of low molecular weight hyaluronic acid (LMW-HA) fragments, where a proportion of the glucosamine moieties were chemically N-acyl substituted. Specifically, N-butyrylation results in anti-inflammatory properties in a macrophage system, and we demonstrate the importance of N-acyl substituents in modulating the inflammatory response of LMW-HA. We have set up an inter-institutional collaborative program to examine the biomedical applications of the N-butyrylated LMW-HA (BHA). In this study, the potentials of BHA for dermal healing are assessed in vitro and in vivo. Consequently, BHA significantly promotes dermal healing relative to a commercial wound care product. By contrast, the “parent” partially de-acetylated LMW-HA (DHA) and the re-acetylated DHA (AHA) significantly delays wound closure, demonstrating the specificity of this N-acylation of LMW-HA in wound healing. Mechanistic studies reveal that the BHA-mediated therapeutic effect is achieved by targeting three phases of wound healing (i.e., inflammation, proliferation and maturation), demonstrating the significant potential of BHA for clinical translation in cutaneous wound healing.

Hyaluronic acid and chitosan-based nanosystems: a new dressing generation for wound care

INTRODUCTION

The main goal in the management of chronic wounds is the development of multifunctional dressings able to promote a rapid recovery of skin structure and function, improving patient compliance.

AREAS COVERED

This review discusses the use of nanosystems, based on hyaluronic acid and chitosan or their derivatives for the local treatment of chronic wounds. The bioactive properties of both polysaccharides will be described, as well as the results obtained in the last decade by the in vitro and in vivo evaluation of the wound healing properties of nanosystems based on such polymers.

EXPERT OPINION

In the last decades, there has been a progressive change in the local treatments of chronic wounds: traditional inert dressings have been replaced by more effective bioactive ones, based on biopolymers taking part in wound healing and able to release the loaded active agents in a controlled way. With the advance of nanotechnologies, the scenario has further changed: nanosystems, characterized by a large area-to-volume ratio, show an improved interaction with the biological substrates, amplifying the activity of the constituent biopolymers. In the coming years, a deeper insight into wound healing mechanisms and the development of new techniques for nanosystem manufacturing will results in the design of new scaffolds with improved performance.

Assessment of silver nanoparticles decorated starch and commercial zinc nanoparticles with respect to their genotoxicity on onion

High throughput production of silver nanoparticles (AgNPs) having controlled size appropriate for industrial purposes were achieved via using facile and ecofriendly chemical reduction method. Native rice starch was used as reductant for silver ions (Ag⁺) to silver atoms (Ag⁰), as well as stabilizing for the obtainable AgNPs. Two different concentrations; 2000 ppm and 4000 ppm were successfully prepared and coded as AgNPs-2000 and AgNPs-4000 respectively. The attained AgNPs were characterized via ultra-visible (UV-vis) spectra, Transmission Electron Microscope (TEM), Energy dispersive X-ray (EDX), Particle size analyzer, polydispersity index (PDI) and zeta potential (ζ-potential). The average particle size of AgNPs (2000 ppm) was 8 nm with PDI = 0.01 which affirm the monodispersity and homogeneity of the produced AgNPs. Meanwhile, the size majority for the as prepared AgNPs (4000 ppm) was 24 nm with PDI = 0.021. Based on the aforementioned data, AgNPs prepared with a high concentration (4000 ppm) compared with the commercialized ZnNPs were used for the genotoxicity study on onion. Root-tips was used for cytogenetic studies using onion (Allium cepa L.) which are excellent materials for cytological and genotoxicity studies. Genotoxicity results explored that, by using AgNPs ≥40 ppm, the abnormalities disturbed chromosomes were observed and detected, that reflects the genotoxicity effect of these nanoparticles at this dose. In addition, the commercial available ZnNPs with the recommended dose (2 g/L) displayed also severe genotoxicity on A. cepa L. root meristem cells.

Potential effects of the combination of nicotinamide, vitamin B2 and vitamin C on oxidative-mediated hepatotoxicity induced by thioacetamide

Background

The liver disease is one of the most important traditional public health problems in Egypt. Oxidative stress is attributed to such pathological condition that further contributes to the initiation and progression of liver injury. In the present study, we have investigated if the strong antioxidant power of Nicotinamide (NA), Vitamin B2 (VB2), and Vitamin C (VC) can ameliorate TAA-induced oxidative stress-mediated liver injury in the rats.

Methods

Thirty-six albino rats were divided into six groups: Control group; TAA group (IP injection with TAA at a dosage of 200 mg/Kg three times a week for two months); TAA + NA group (rats administered with NA at a dosage of 200 mg/kg daily besides TAA as in the control); TAA + VB2 group (rats administered with vitamin B2 at a dosage of 30 mg/kg daily besides injection with TAA); TAA + VC group (rats administered with vitamin C at a dosage of 200 mg/kg daily along with injection of TAA). TAA + NA + VB + VC group (rats administered the with the three vitamins daily in TAA pre-injected at the respective doses described above).

Results

Treatment of rats with TAA led to a significant elevation of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), total bilirubin, cholesterol, triglycerides, low-density lipoprotein (LDL) and tumor necrosis factor-alpha (TNF-α) in the serum samples. Moreover, malondialdehyde (MDA), hydroxyproline and nitic oxide (NO) were also significantly increased in the TAA-treated rats, while reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) were significantly compromised in the hepatic samples. Rats administered with NA, VB2, and VC as individually or in combination ameliorated the deleterious effects of TAA that was confirmed by histopathology. However, the combination of the three vitamins was found more effective as compared to each of the vitamins.

Conclusion

Our work demonstrates that NA, VB2, and VC cross-talk with each other that act as a more potent biochemical chain of antioxidant defense against TAA-induced toxicities in vivo.

BLT2 expression improves skin integrity and protects from alterations caused by hyperglycemia in type 2 diabetes

Type 2 diabetes (T2D) can go undiagnosed for years, leading to a stage where chronic high blood sugar produces complications such as delayed wound healing. Reports have shown that BLT2 activation improves keratinocyte migration and wound healing, as well as protecting the epidermal barrier through the promotion of actin polymerization. The goal of this study was to elucidate the role of BLT2 expression in skin epithelial integrity in T2D. For this purpose, we used both wild type (WT) and BLT2 knockout mice in a model, in which a T2D-like phenotype was induced by keeping the animals on a high fat (HF) diet over 5 weeks. In a parallel in vitro approach, we cultured BLT2-transfected HaCaT cells at both low and high glucose concentrations for 48 h. Structure, transepithelial resistance (TEER), IL-1ß, IL-8 or CXCL2, MMP9, Filaggrin, Loricrin and Keratin 10 (K10) were evaluated ex vivo and in vitro. Additionally, wound healing (WH) was studied in vitro. The skin from T2D and BLT2 knockout mice showed a reduction in TEER and the expression of IL-1ß, and in increase in CXCL2, MMP9, Filaggrin, Loricrin and K10 expression. The structure suggested an atrophic epidermis; however, the skin was dramatically affected in the BLT2 knockout mice kept on a HF diet. HaCaT-BLT2 cells presented as an organized monolayer and showed higher TEER and wound healing compared with vector only-transfected HaCaT-Mock cells. Likewise, alterations in the expression of skin inflammatory, matrix degradation and differentiation markers under low and high glucose conditions were less severe than in HaCaT-Mock cells. Our results suggest that BLT2 improves epithelial integrity and function by regulating differentiation markers, cytokines and MMP9. Furthermore, BLT2 attenuates the damaging effects of high glucose levels, thereby accelerating wound healing.