A multifunctional in situ-forming hydrogel for wound healing

THE USE OF POLOXAMER 188 IN BURN INJURY TREATMENT: A SYSTEMATIC LITERATURE REVIEW

ABSTRACT

Although there have been numerous advancements in burn wound management, burn injuries are still a major cause of morbidity and mortality in the United States, and novel therapeutics are still needed to improve outcomes. Poloxamer 188 (P188) is a synthetic copolymer with Food and Drug Administration (FDA) approval that has many biological applications. This study aimed to review the literature on P188 in burn injuries and its effects based on burn mechanisms. We employed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to complete this systematic literature review. We searched the databases of Google Scholar, PubMed, and SCOPUS using the keywords burn, p188, poloxamer 188, and pluronic F68 in combination. Two reviewers independently screened the articles for inclusion. Articles that were not in English, were book chapters or conference proceedings, or did not evaluate P188 in the setting of burn injuries were excluded. We included a total of 33 full-text articles with both in vivo and in vitro preclinical studies. P188 was found to be beneficial in animal and cell studies evaluating electrical and thermal burn injuries. P188 was also found to be useful in burn wound management. Although its utility may be limited in radiation injuries, P188 may be helpful in delaying the initial damage caused by radiation burns. P188 therefore has the potential to be used as a therapy in both burn wound management and in the treatment of systemic injuries sustained through burns. Future studies should aim to assess the efficacy of P188 in clinical models of burn injury.

l-Carnosine loaded on carboxymethyl cellulose hydrogels for promoting wound healing

Wound management remains a challenge in clinical practice. Nowadays, patients have an increasing demand for wound repair with enhanced speed and quality; therefore, there is a great need to seek therapeutic strategies that can promote rapid and effective wound healing. In this study, we developed a carboxymethyl cellulose hydrogel loaded with l-carnosine (CRN@hydrogel) for potential application as a wound dressing. In vitro experiments confirmed that CRN@hydrogel can release over 80% of the drug within 48 h and demonstrated its favorable cytocompatibility and blood compatibility, thus establishing its applicability for safe utilization in clinical practice. Using a rat model, we found that this hydrogel could promote and accelerate wound healing more effectively. These results indicate that the novel hydrogel can serve as an efficient therapeutic strategy for wound treatment.

Biodegradable Polymers in Veterinary Medicine-A Review

During the past two decades, tremendous progress has been made in the development of biodegradable polymeric materials for various industrial applications, including human and veterinary medicine. They are promising alternatives to commonly used non-degradable polymers to combat the global plastic waste crisis. Among biodegradable polymers used, or potentially applicable to, veterinary medicine are natural polysaccharides, such as chitin, chitosan, and cellulose as well as various polyesters, including poly(ε-caprolactone), polylactic acid, poly(lactic-co-glycolic acid), and polyhydroxyalkanoates produced by bacteria. They can be used as implants, drug carriers, or biomaterials in tissue engineering and wound management. Their use in veterinary practice depends on their biocompatibility, inertness to living tissue, mechanical resistance, and sorption characteristics. They must be designed specifically to fit their purpose, whether it be: (1) facilitating new tissue growth and allowing for controlled interactions with living cells or cell-growth factors, (2) having mechanical properties that address functionality when applied as implants, or (3) having controlled degradability to deliver drugs to their targeted location when applied as drug-delivery vehicles. This paper aims to present recent developments in the research on biodegradable polymers in veterinary medicine and highlight the challenges and future perspectives in this area.

Hydrogel Breakthroughs in Biomedicine: Recent Advances and Implications

OBJECTIVE

The objective of this review is to present a succinct summary of the latest advancements in the utilization of hydrogels for diverse biomedical applications, with a particular focus on their revolutionary impact in augmenting the delivery of drugs, tissue engineering, along with diagnostic methodologies.

METHODS

Using a meticulous examination of current literary works, this review systematically scrutinizes the nascent patterns in applying hydrogels for biomedical progress, condensing crucial discoveries to offer a comprehensive outlook on their ever-changing importance.

RESULTS

The analysis presents compelling evidence regarding the growing importance of hydrogels in biomedicine. It highlights their potential to significantly enhance drug delivery accuracy, redefine tissue engineering strategies, and advance diagnostic techniques. This substantiates their position as a fundamental element in the progress of modern medicine.

CONCLUSION

In summary, the constantly evolving advancement of hydrogel applications in biomedicine calls for ongoing investigation and resources, given their diverse contributions that can revolutionize therapeutic approaches and diagnostic methods, thereby paving the way for improved patient well-being.

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.

Effects of Poloxamers as Excipients on the Physicomechanical Properties, Cellular Biocompatibility, and In Vitro Drug Release of Electrospun Polycaprolactone (PCL) Fibers

Electrospun microfibers are emerging as one of the advanced wound dressing materials for acute and/or chronic wounds, especially with their ability to carry drugs and excipients at a high loading while being able to deliver them in a controlled manner. Various attempts were made to include excipients in electrospun microfibers as wound dressing materials, and one of them is poloxamer, an amphiphilic polymer that exhibits wound debridement characteristics. In this study, we formulated two types of poloxamers (i.e., P188 and P338) at 30% (w/w) loading into electrospun polycaprolactone (PCL) fibers to evaluate their physicomechanical properties, biocompatibility, and in vitro drug release of a model drug. Our findings showed that the incorporation of poloxamers in the PCL solutions during electrospinning resulted in a greater "whipping" process for a larger fiber deposition area. These fibers were mechanically stiffer and stronger, but less ductile as compared to the PCL control fibers. The incorporation of poloxamers into electrospun PCL fibers reduced the surface hydrophobicity of fibers according to our water contact angle studies and in vitro degradation studies. The fibers' mechanical properties returned to those of the PCL control groups after "dumping" the poloxamers. Moreover, poloxamer-loaded PCL fibers accelerated the in vitro release of the model drug due to surface wettability. These poloxamer-loaded PCL fibers were biocompatible, as validated by MTT assays using A549 cells. Overall, we demonstrated the ability to achieve a high loading of poloxamers in electrospun fibers for wound dressing applications. This work provided the basic scientific understanding of materials science and bioengineering with an emphasis on the engineering applications of advanced wound dressings.

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.

Silva-Filho E, Estevinho LM. Antibacterial and Healing Effect of Chicha Gum Hydrogel (Sterculia striata) with Nerolidol

Chicha gum is a natural polymer obtained from the Sterculia striata plant. The hydroxyl groups of its structure have a chemical affinity to form hydrogels, which favors the association with biologically active molecules, such as nerolidol. This association improves the biological properties and allows the material to be used in drug delivery systems. Chicha gum hydrogels associated with nerolidol were produced at two concentrations: 0.01 and 0.02 g mL-1. Then, the hydrogels were characterized by thermogravimetry (TG), Fourier Transform Infrared spectroscopy (FTIR), and rheological analysis. The antibacterial activity was tested against Staphylococcus aureus and Escherichia coli. The cytotoxicity was evaluated against Artemia salina. Finally, an in vivo healing assay was carried out. The infrared characterization indicated that interactions were formed during the gel reticulation. This implies the presence of nerolidol in the regions at 3100-3550 cm-1. The rheological properties changed with an increasing concentration of nerolidol, which resulted in less viscous materials. An antibacterial 83.6% growth inhibition effect was observed using the hydrogel with 0.02 g mL-1 nerolidol. The in vivo healing assay showed the practical activity of the hydrogels in the wound treatment, as the materials promoted efficient re-epithelialization. Therefore, it was concluded that the chicha hydrogels have the potential to be used as wound-healing products.

Advanced Multifunctional Wound Dressing Hydrogels as Drug Carriers

Skin injuries, especially chronic wounds, remain a significant healthcare system problem. The number of burns, diabetic patients, pressure ulcers, and other damages is also growing, particularly in elderly populations. Several investigations are pursued in designing more effective therapeutics for treating different wound injuries. These efforts have resulted in developing multifunctional wound dressings to improve wound repair. For this, preparing multifunctional dressings using various methods has provided a new attitude to support effective skin regeneration. This review focuses on the recent developments in designing multifunctional hydrogel dressings with hemostasis, adhesiveness, antibacterial, and antioxidant properties.

A Review on Chitosan and Cellulose Hydrogels for Wound Dressings

Wound management remains a challenging issue around the world, although a lot of wound dressing materials have been produced for the treatment of chronic and acute wounds. Wound healing is a highly dynamic and complex regulatory process that involves four principal integrated phases, including hemostasis, inflammation, proliferation, and remodeling. Chronic non-healing wounds are wounds that heal significantly more slowly, fail to progress to all the phases of the normal wound healing process, and are usually stalled at the inflammatory phase. These wounds cause a lot of challenges to patients, such as severe emotional and physical stress and generate a considerable financial burden on patients and the general public healthcare system. It has been reported that about 1-2% of the global population suffers from chronic non-healing wounds during their lifetime in developed nations. Traditional wound dressings are dry, and therefore cannot provide moist environment for wound healing and do not possess antibacterial properties. Wound dressings that are currently used consist of bandages, films, foams, patches and hydrogels. Currently, hydrogels are gaining much attention as a result of their water-holding capacity, providing a moist wound-healing milieu. Chitosan is a biopolymer that has gained a lot of attention recently in the pharmaceutical industry due to its unique chemical and antibacterial nature. However, with its poor mechanical properties, chitosan is incorporated with other biopolymers, such as the cellulose of desirable biocompatibility, at the same time having the improved mechanical and physical properties of the hydrogels. This review focuses on the study of biopolymers, such as cellulose and chitosan hydrogels, for wound treatment.

Antibacterial biomaterials for skin wound dressing

Bacterial infection and the ever-increasing bacterial resistance have imposed severe threat to human health. And bacterial contamination could significantly menace the wound healing process. Considering the sophisticated wound healing process, novel strategies for skin tissue engineering are focused on the integration of bioactive ingredients, antibacterial agents included, into biomaterials with different morphologies to improve cell behaviors and promote wound healing. However, a comprehensive review on anti-bacterial wound dressing to enhance wound healing has not been reported. In this review, various antibacterial biomaterials as wound dressings will be discussed. Different kinds of antibacterial agents, including antibiotics, nanoparticles (metal and metallic oxides, light-induced antibacterial agents), cationic organic agents, and others, and their recent advances are summarized. Biomaterial selection and fabrication of biomaterials with different structures and forms, including films, hydrogel, electrospun nanofibers, sponge, foam and three-dimension (3D) printed scaffold for skin regeneration, are elaborated discussed. Current challenges and the future perspectives are presented in this multidisciplinary field. We envision that this review will provide a general insight to the elegant design and further refinement of wound dressing.

Nasal Delivery of Cinnarizine Thermo- and Ion-Sensitive In Situ Hydrogels for Treatment of Microwave-Induced Brain Injury

(1) Background: When the body is exposed to microwave radiation, the brain is more susceptible to damage than other organs. However, few effective drugs are available for the treatment of microwave-induced brain injury (MIBI) because most drugs are difficult to cross the blood–brain barrier (BBB) to reach the brain. (2) Methods: Nasal cinnarizine inclusion complexes with thermo-and ion-sensitive hydrogels (cinnarizine ISGs) were prepared to treat MIBI and the characteristics of the inclusion complexes and their thermo-and ion-sensitive hydrogels were evaluated. (3) Results: Due to high viscosity, cinnarizine ISGs can achieve long-term retention in the nasal cavity to achieve a sustained release effect. Compared with the model, the intranasal thermo-and ion-sensitive cinnarizine ISGs significantly improved the microwave-induced spatial memory and spontaneous exploration behavior with Morris water maze and open field tests. Cinnarizine ISGs inhibited the expression of calcineurin and calpain 1 in the brain, which may be related to the inhibition of calcium overload by cinnarizine. (4) Conclusion: Intranasal thermo- and ion-sensitive cinnarizine ISGs are a promising brain-targeted pharmaceutical preparation against MIBI.

Haemostatic materials for wound healing applications

Wounds are one of the most common health issues, and the cost of wound care and healing has continued to increase over the past decade. The first step in wound healing is haemostasis, and the development of haemostatic materials that aid wound healing has accelerated in the past 5 years. Numerous haemostatic materials have been fabricated, composed of different active components (including natural polymers, synthetic polymers, silicon-based materials and metal-containing materials) and in various forms (including sponges, hydrogels, nanofibres and particles). In this Review, we provide an overview of haemostatic materials in wound healing, focusing on their chemical design and operation. We describe the physiological process of haemostasis to elucidate the principles that underpin the design of haemostatic wound dressings. We also highlight the advantages and limitations of the different active components and forms of haemostatic materials. The main challenges and future directions in the development of haemostatic materials for wound healing are proposed.

Functional Hydrogels as Wound Dressing to Enhance Wound Healing

Hydrogels, due to their excellent biochemical and mechnical property, have shown attractive advantages in the field of wound dressings. However, a comprehensive review of the functional hydrogel as a wound dressing is still lacking. This work first summarizes the skin wound healing process and relates evaluation parameters and then reviews the advanced functions of hydrogel dressings such as antimicrobial property, adhesion and hemostasis, anti-inflammatory and anti-oxidation, substance delivery, self-healing, stimulus response, conductivity, and the recently emerged wound monitoring feature, and the strategies adopted to achieve these functions are all classified and discussed. Furthermore, applications of hydrogel wound dressing for the treatment of different types of wounds such as incisional wound and the excisional wound are summarized. Chronic wounds are also mentioned, and the focus of attention on infected wounds, burn wounds, and diabetic wounds is discussed. Finally, the future directions of hydrogel wound dressings for wound healing are further proposed.

Bioresponsive Hybrid Nanofibers Enable Controlled Drug Delivery through Glass Transition Switching at Physiological Temperature

To avoid excessive usage of antibiotics and antimicrobial agents, smart wound dressings permitting controlled drug release for treatment of bacterial infections are highly desired. In search of a sensitive stimulus to activate drug release under physiological conditions, we found that the glass transition temperature (T_g) of a polymer or polymer blend can be an ideal parameter because a thermal stimulus can regulate drug release at the physiological temperature of 37 °C. A well-tuned T_g for a controlled drug release from fibers at 37 °C was achieved by varying the blending ratio of Eudragit® RS 100 and poly(methyl methacrylate). Octenidine, an antimicrobial agent often used in wound treatment, was encapsulated into the polymer blend during the electrospinning process and evaluated for its controlled release based on modulation of temperature. The thermal switch of the nanofibrous membranes can be turned "on" at physiological temperature (37 °C) and "off" at room temperature (25 °C), conferring a controlled release of octenidine. It was found that octenidine can be released in an amount at least 8.5 times higher (25 mg·L^-1) during the "on" stage compared to the "off" stage after 24 h, which was regulated by the wet T_g (34.8-36.5 °C). The "on"/"off" switch for controlled drug release can moreover be repeated at least 5 times. Furthermore, the fabricated nanofibrous membranes displayed a distinctive antibacterial activity, causing a log3 reduction of the viable cells for both Gram negative and positive pathogens at 37 °C, when the thermal switch was "on". This study forms the groundwork for a treatment concept where no external stimulus is needed for the release of antimicrobials at physiological conditions, and will help reduce the overuse of antibiotics by allowing controlled drug release.

Classification and Production of Polymeric Foams among the Systems for Wound Treatment

This work represents an overview on types of wounds according to their definition, classification and dressing treatments. Natural and synthetic polymeric wound dressings types have been analyzed, providing a historical overview, from ancient to modern times. Currently, there is a wide choice of materials for the treatment of wounds, such as hydrocolloids, polyurethane and alginate patches, wafers, hydrogels and semi-permeable film dressings. These systems are often loaded with drugs such as antibiotics for the simultaneous delivery of drugs to prevent or cure infections caused by the exposition of blood vessel to open air. Among the presented techniques, a focus on foams has been provided, describing the most diffused branded products and their chemical, physical, biological and mechanical properties. Conventional and high-pressure methods for the production of foams for wound dressing are also analyzed in this work, with a proposed comparison in terms of process steps, efficiency and removal of solvent residue. Case studies, in vivo tests and models have been reported to identify the real applications of the produced foams.

Therapeutic effects of chitosan in veterinary dermatology: A systematic review of the literature

Chitosan is a natural polysaccharide with biocompatibility, biodegradability, nontoxicity, antimicrobial, and hemostatic properties. This biopolymer has been used in different pharmaceutical forms; therefore, it has an attractive potential for dermal applications in veterinary medicine. The aim of this review is to assess the healing potential of chitosan, based on its dermatological effects on animals, to enrich the therapeutic options of veterinary clinicians. A systematic review was conducted based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) strategy, retrieving 1,032 studies and selecting 39 after the inclusion and exclusion criteria were applied. The studies included reports with confirmed positive effects (n = 46/99, 46.5 %) (P < 0.05), with positive effects (n = 49.5/99, 49.5 %), and with no effect (n = 4/99, 4 %); none of the studies reported adverse effects. There is an association between frequency of application and a decrease in healing time (P = 0.038); applying chitosan "every 48-72 hours" was the most recommended frequency (n = 10/19, 52.9 %). Chitosan, when applied to skin lesions on animals, produces positive effects on healing, potentially becoming a safe biomaterial for skin treatments in veterinary practice. As an initial protocol, we suggest applying chitosan every 48-72 hours for at least 2 weeks (7 applications).

Textile Materials Modified with Stimuli-Responsive Drug Carrier for Skin Topical and Transdermal Delivery

Textile materials, as a suitable matrix for different active substances facilitating their gradual release, can have an important role in skin topical or transdermal therapy. Characterized by compositional and structural variety, those materials readily meet the requirements for applications in specific therapies. Aromatherapy, antimicrobial substances and painkillers, hormone therapy, psoriasis treatment, atopic dermatitis, melanoma, etc., are some of the areas where textiles can be used as carriers. There are versatile optional methods for loading the biologically active substances onto textile materials. The oldest ones are by exhaustion, spraying, and a pad-dry-cure method. Another widespread method is the microencapsulation. The modification of textile materials with stimuli-responsive polymers is a perspective route to obtaining new textiles of improved multifunctional properties and intelligent response. In recent years, research has focused on new structures such as dendrimers, polymer micelles, liposomes, polymer nanoparticles, and hydrogels. Numerous functional groups and the ability to encapsulate different substances define dendrimer molecules as promising carriers for drug delivery. Hydrogels are also high molecular hydrophilic structures that can be used to modify textile material. They absorb a large amount of water or biological fluids and can support the delivery of medicines. These characteristics correspond to one of the current trends in the development of materials used in transdermal therapy, namely production of intelligent materials, i.e., such that allow controlled concentration and time delivery of the active substance and simultaneous visualization of the process, which can only be achieved with appropriate and purposeful modification of the textile material.

Ibuprofen-Loaded Heparin Modified Thermosensitive Hydrogel for Inhibiting Excessive Inflammation and Promoting Wound Healing

Hydrogels have been investigated as ideal biomaterials for wound treatment owing to their ability to form a highly moist environment which accelerates cell migration and tissue regeneration for prompt wound healing. They can also be used as a drug carrier for local delivery, and are able to activate immune cells to enhance wound healing. Here, we developed heparin-conjugated poly(N-isopropylacrylamide), an injectable, in situ gel-forming polymer, and evaluated its use in wound healing. Ibuprofen was encapsulated into the hydrogel to help reduce pain and excessive inflammation during healing. In addition to in vitro studies, a BALB/c mice model was used to evaluate its effect on would healing and the secretion of inflammatory mediators. The in vitro assay confirmed that the ibuprofen released from the hydrogel dramatically reduced lipopolysaccharide-induced inflammation by suppressing the production of NO, PGE2 and TNF-α in RAW264.7 macrophages. Moreover, an in vivo wound healing assay was conducted by applying hydrogels to wounds on the backs of mice. The results showed that the ibuprofen-loaded hydrogel improved healing relative to the phosphate buffered saline group. This study indicates that ibuprofen loaded in an injectable hydrogel is a promising candidate for wound healing therapy.

Biocompatible Gels of Chitosan-Buriti Oil for Potential Wound Healing Applications

The buriti oil (Mauritia flexuosa L.) can be associated with polymeric matrices for biomedical applications. This study aimed to evaluate the effect of chitosan gel (CG) associated with buriti oil (CGB) as a healing agent. The fatty acids and volatile compounds composition of buriti oil were performed and the composite gels were characterized using FTIR and thermal analysis. Biological tests including antimicrobial, antioxidant, anti-inflammatory and healing effects were also investigated. Buriti oil is composed of oleic and palmitic acids, and the main volatile compounds were identified. The buriti oil did not show antimicrobial activity, on the other hand, the composite gel (chitosan and oil) proved to be efficient against Staphylococcus aureus and Klebsiella pneumonia at the 10 mg/mL. Similar behavior was observed for antioxidant activity, determined by the β-carotene bleaching assay, composite gels presenting higher activity and buriti oil showed anti-inflammatory activity, which may be related to the inhibition of the release of free radicals. Regarding wound healing performed using in vivo testing, the composite gel (CGB) was found to promote faster and complete wound retraction. The results indicated that the gel chitosan–buriti oil has a set of properties that improve its antibacterial, antioxidant and healing action, suggesting that this material can be used to treat skin lesions.

Frequent template switching in postreplication gaps: suppression of deleterious consequences by the Escherichia coli Uup and RadD proteins

When replication forks encounter template DNA lesions, the lesion is simply skipped in some cases. The resulting lesion-containing gap must be converted to duplex DNA to permit repair. Some gap filling occurs via template switching, a process that generates recombination-like branched DNA intermediates. The Escherichia coli Uup and RadD proteins function in different pathways to process the branched intermediates. Uup is a UvrA-like ABC family ATPase. RadD is a RecQ-like SF2 family ATPase. Loss of both functions uncovers frequent and RecA-independent deletion events in a plasmid-based assay. Elevated levels of crossing over and repeat expansions accompany these deletion events, indicating that many, if not most, of these events are associated with template switching in postreplication gaps as opposed to simple replication slippage. The deletion data underpin simulations indicating that multiple postreplication gaps may be generated per replication cycle. Both Uup and RadD bind to branched DNAs in vitro. RadD protein suppresses crossovers and Uup prevents nucleoid mis-segregation. Loss of Uup and RadD function increases sensitivity to ciprofloxacin. We present Uup and RadD as genomic guardians. These proteins govern two pathways for resolution of branched DNA intermediates such that potentially deleterious genome rearrangements arising from frequent template switching are averted.

Xanthan Gum-Konjac Glucomannan Blend Hydrogel for Wound Healing

Hydrogels are considered to be the most ideal materials for the production of wound dressings since they display a three-dimensional structure that mimics the native extracellular matrix of skin as well as a high-water content, which confers a moist environment at the wound site. Until now, different polymers have been used, alone or blended, for the production of hydrogels aimed for this biomedical application. From the best of our knowledge, the application of a xanthan gum-konjac glucomannan blend has not been used for the production of wound dressings. Herein, a thermo-reversible hydrogel composed of xanthan gum-konjac glucomannan (at different concentrations (1% and 2% w/v) and ratios (50/50 and 60/40)) was produced and characterized. The obtained data emphasize the excellent physicochemical and biological properties of the produced hydrogels, which are suitable for their future application as wound dressings.

In Situ Crosslinking Bionanocomposite Hydrogels with Potential for Wound Healing Applications

In situ forming hydrogels are a class of biomaterials that can fulfil a variety of important biomedically relevant functions and hold promise for the emerging field of patient-specific treatments (e.g., cell therapy, drug delivery). Here we report the results of our investigations on the generation of in situ forming hydrogels with potential for wound healing applications (e.g., complex blast injuries). The combination of polysaccharides that were oxidized to display aldehydes, amine displaying chitosan and nanostructured ZnO yields in situ forming bionanocomposite hydrogels. The physicochemical properties of the components, their cytotoxicity towards HaCat cells and the in vitro release of zinc ions on synthetic skin were studied. The in situ gel formation process was complete within minutes, the components were non-toxic towards HaCat cells at functional levels, Zn²⁺ was released from the gels, and such materials may facilitate wound healing.

Uptake and Release of Species from Carbohydrate Containing Organogels and Hydrogels

Hydrogels are used for a variety of technical and medical applications capitalizing on their three-dimensional (3D) cross-linked polymeric structures and ability to act as a reservoir for encapsulated species (potentially encapsulating or releasing them in response to environmental stimuli). In this study, carbohydrate-based organogels were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization of a β-D-glucose pentaacetate containing methacrylate monomer (Ac-glu-HEMA) in the presence of a di-vinyl cross-linker; these organogels could be converted to hydrogels by treatment with sodium methoxide (NaOMe). These materials were studied using solid state ¹³C cross-polarization/magic-angle spinning (CP/MAS) NMR, Fourier transform infrared (FTIR) spectroscopy, and field emission scanning electron microscopy (FE-SEM). The swelling of the gels in both organic solvents and water were studied, as was their ability to absorb model bioactive molecules (the cationic dyes methylene blue (MB) and rhodamine B (RhB)) and absorb/release silver nitrate, demonstrating such gels have potential for environmental and biomedical applications.

Photothermal-Induced Antibacterial Activity of Gold Nanorods Loaded into Polymeric Hydrogel against Pseudomonas aeruginosa Biofilm

In this study, the photothermal-induced bactericidal activity of phospholipid-decorated gold nanorods (DSPE-AuNR) suspension against Pseudomonas aeruginosa planktonic and biofilm cultures was investigated. We found that the treatment of planktonic culture of Pseudomonas aeruginosa with DSPE-AuNR suspension (0.25-0.03 nM) followed by a continuous laser beam exposure resulted in ~6 log cycle reduction of the bacterial viable count in comparison to the control. The percentage reduction of Pseudomonas aeruginosa biofilm viable count was ~2.5-6.0 log cycle upon laser excitation with different concentrations of DSPE-AuNR as compared to the control. The photothermal ablation activity of DSPE-AuNR (0.125 nM) loaded into poloxamer 407 hydrogel against Pseudomonas aeruginosa biofilm resulted in ~4.5-5 log cycle reduction in the biofilm viable count compared to the control. Moreover, transmission electron microscope (TEM) images of the photothermally-treated bacteria revealed a significant change in the bacterial shape and lysis of the bacterial cell membrane in comparison to the untreated bacteria. Furthermore, the results revealed that continuous and pulse laser beam modes effected a comparable photothermal-induced bactericidal activity. Therefore, it can be concluded that phospholipid-coated gold nanorods present a promising nanoplatform to eradicate Pseudomonas aeruginosa biofilm responsible for common skin diseases.

3D printed mold-based capsaicin candy for the treatment of oral ulcer

Oral ulcer is one common mucosal disease with high prevalence. Here, capsaicin candies were prepared based on the stereolithographically (SLA) 3D printed molds. The molds can be freely designed depending on the needs of patients, involving symmetric shapes (e.g., round, four-lead clover and cube), asymmetric shapes (e.g., car) and various color (e.g., blue, red and yellow). A two-part-combined mold was filled with the xylitol-based material and separated to obtain hard candies. Capsaicin was amorphous in the candies according to the differential scanning calorimetry and X-ray diffraction. Poloxamer 188 improved the release of capsaicin from the candies. Rat oral ulcer models were established on the tongue with phenol liquids. The blank candy, 0.05% capsaicin candy and dexamethasone were respectively administered on the ulcer once daily. On Day 7, a healing rate of 97.8% was achieved by the capsaicin candy, much higher than those in the other groups. Moreover, the blank candy also showed the remarkable ulcer healing effect due to the presence of xylitol and poloxamer. Capsaicin remarkably enhanced the reepithelialization of ulcer tissues and showed strong anti-inflammatory effect by reducing the expressions of THF-α and IL-6. 3D printing-based capsaicin candies provide an interesting therapeutic choice for the people with oral ulcer.

Curcumin solid dispersion-loaded in situ hydrogels for local treatment of injured vaginal bacterial infection and improvement of vaginal wound healing

OBJECTIVES

Injured vaginal infection is detrimental to women. A curcumin hydrogel was studied for local treatment of injured vaginal infection.

METHODS

Curcumin solid dispersions (CSDs) were prepared from polyvinyl pyrrolidone and characterized by differential scanning calorimetry and an X-ray diffraction method. An in situ hydrogel CSD hydrogel (CSDG) was prepared with CSD/poloxamers and characterized. In vitro curcumin release and antibacterial effects of CSDs, CSDGs and curcumin were compared. The therapeutic effect of the CSDGs and Lincomycin/Lidocaine Gel was explored after intravaginal administration on the injured rat vaginal infection models.

KEY FINDINGS

Curcumin was amorphous in CSDs where curcumin rapidly released in simulated vaginal fluids. However, CSDGs showed sustained release. CSDGs quickly formed gels in the vagina. CSDGs showed high in vivo anti-Escherichia coli or Staphylococcus aureus effect though weak in vitro effect. The recovery of vaginal microenvironment and improvement of intravaginal Lactobacillus growth may be the major reason. Furthermore, CSDGs remarkably improved vaginal wound healing by alleviating inflammation and restoring vaginal epidermal tissues compared with the Lincomycin/Lidocaine Gel.

CONCLUSION

CSDGs are a promising topical formulation for local treatment of vaginal bacterial infection and improvement of vaginal wound healing.

Hydrogel-Based Strategies to Advance Therapies for Chronic Skin Wounds

Chronic skin wounds are the leading cause of nontraumatic foot amputations worldwide and present a significant risk of morbidity and mortality due to the lack of efficient therapies. The intrinsic characteristics of hydrogels allow them to benefit cutaneous healing essentially by supporting a moist environment. This property has long been explored in wound management to aid in autolytic debridement. However, chronic wounds require additional therapeutic features that can be provided by a combination of hydrogels with biochemical mediators or cells, promoting faster and better healing. We survey hydrogel-based approaches with potential to improve the healing of chronic wounds by reviewing their effects as observed in preclinical models. Topics covered include strategies to ablate infection and resolve inflammation, the delivery of bioactive agents to accelerate healing, and tissue engineering approaches for skin regeneration. The article concludes by considering the relevance of treating chronic skin wounds using hydrogel-based strategies.

Surfactants: Role in biofilm management and cellular behaviour

Appropriate and effective wound cleaning represents an important process that is necessary for preparing the wound for improved wound healing and for helping to dislodge biofilms. Wound cleaning is of paramount importance to wound bed preparation for helping to enhance wound healing. Surfactant applications in wound care may represent an important area in the cleaning continuum. However, understanding of the role and significance of surfactants in wound cleansing, biofilm prevention and control, and enhancing cellular viability and proliferation is currently lacking. Despite this, some recent evidence on poloxamer-based surfactants where the surfactants are present in high concentration have been shown to have an important role to play in biofilm management; matrix metalloproteinase modulation; reducing inflammation; and enhancing cellular proliferation, behaviour, and viability. Consequently, this review aims to discuss the role, mode of action, and clinical significance of the use of medically accepted surfactants, with a focus on concentrated poloxamer-based surfactants, to wound healing but, more specifically, the role they may play in biofilm management and effects on cellular repair.

Sodium alginate in oil-poloxamer organogels for intravaginal drug delivery: Influence on structural parameters, drug release mechanisms, cytotoxicity and in vitro antifungal activity

Local administration of antimicrobial agents is the first therapeutic approach for the treatment of Candida albicans infections. The duration of contact of formulations with the vaginal mucosa is critical for therapeutic efficacy. This study describes the development of organogels employing an oil phase composed of oleic acid (OA) and an aqueous phase consisting of the poloxamer PL₄₀₇, alone or in association with PL₁₈₈, together with 0.25-1% sodium alginate (SA), in order to obtain an intravaginal drug delivery system capable of modulating the release of voriconazole (VRC). VRC was solubilized in oleic acid homogenized with the PL-SA aqueous phase, at a final concentration of 5 mg/mL. Physicochemical characterization was performed for evaluation of the influence of SA on organogel structural organization, biopharmaceutical properties, pharmacological efficacy, and cytotoxicity, envisaging use of the formulation for the treatment of vaginal candidiasis. The enthalpy variation values showed greater changes in the presence of PL₁₈₈ and after the incorporation of SA or VRC in the organogels. Rheological analysis showed T_sol-gel values in the ranges 11-39 °C and 27-30 °C for the OA-PL₄₀₇ and OA-PL_407-188 formulations, respectively. Oscillatory analysis of OA-PL_407-188 showed that G' was ~20-fold higher than G″, even after submitting the formulation to temperature variation. VRC-OA-PL₄₀₇ showed fast drug release from 0.5 to 4 h, maintaining total release (~100%) up to 24 h. The incorporation of SA in the organogels enabled modulation of VRC release, with different release percentages for 0.25% SA (~75%), 0.5% SA (~55%), and 1% SA (~35%). The formulation was non-cytotoxic towards HeLa and Vero cell lines. In diffusion tests, it was able to prevent the growth of Candida albicans and Candida krusei. In conclusion, the results suggested that OA-PL_407-188-SA organogels could be possible new systems for VRC delivery, with potential for use in future vaginal applications.

A novel injectable thermo-sensitive binary hydrogels system for facilitating endoscopic submucosal dissection procedure

Background and aims

Making an optimal and lasting submucosal cushion is critical for endoscopic submucosal dissection. The thermo-sensitive binary hydrogels system composed of poloxamer 407 and poloxamer 188 might be an excellent submucosal injection solution considering the unique feature that it remains liquid at room temperature and becomes gelatinous after being injected in the submucosa of the digestive tract. The present study focuses on preparing the thermo-sensitive binary hydrogels system and testing its capacity in mucosal lifting and its role in the endoscopic submucosal dissection procedure.

Methods

Various concentrations of poloxamer 407 and poloxamer 188 were added to normal saline. The gelation temperature viscosity of the thermo-sensitive binary hydrogels system was measured to choose the best formula. The thermo-sensitive binary hydrogels system and normal saline were first compared in extracted porcine stomach. For in vivo study, the thermo-sensitive binary hydrogels system and normal saline were compared for facilitating the endoscopic submucosal dissection procedure.

Results

Among the 46 kinds of thermo-sensitive binary hydrogels system, gelation temperatures of the thermo-sensitive binary hydrogels system I (poloxamer 407/poloxamer 188, 17%/0.5%, w/w) and the thermo-sensitive binary hydrogels system II (poloxamer 407/poloxamer 188, 18%/2%, w/w) were among the ideal range of gelation temperature. The injecting pressure in vitro study of thermo-sensitive binary hydrogels system II was significantly higher than that of thermo-sensitive binary hydrogels system I and normal saline (p < 0.001). Sixteen gastric endoscopic submucosal dissection procedures were performed in a porcine model. The initial volume of normal saline injection (13.88 ± 3.91 ml vs 5.88 ± 3.44 ml, p = 0.001) was significantly larger than the thermo-sensitive binary hydrogels system group. The postoperative wound showed a significant difference in the two groups (p = 0.023) indicating that the thermo-sensitive binary hydrogels system can create a cleaner wound.

Conclusions

Considering the gelation temperature, viscosity, injection pressure, and the height of the mucosal elevation, the thermo-sensitive binary hydrogels system I was the better submucosal injection solution.

Effects of nanozeolite/starch thermoplastic hydrogels on wound healing

BACKGROUND

Wound healing is a complex biological process. Some injuries lead to chronic nonhealing ulcers, and healing process is a challenge to both the patient and the medical team. We still look forward an appropriate wound dressing.

MATERIALS AND METHODS

In this study, starch-based nanocomposite hydrogel scaffolds reinforced by zeolite nanoparticles (nZ) were prepared for wound dressing. In addition, a herbal drug (chamomile extract) was added into the matrix to accelerate healing process. To estimate the cytocompatibility of hydrogel dressings, fibroblast mouse cells (L929) were cultured on scaffolds. Then, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium-bromide assay test and interaction of cells and scaffolds were evaluated. For evaluating healing process, 48 male rats were randomly divided into four groups of four animals each (16 rats at each step). The ulcers of the first group were treated with the same size of pure hydrogels. The second group received a bandage with the same size of hydrogel/extract/4 wt% nZ (hydrogel NZE). The third group was treated with chamomile extract, and the fourth group was considered as control without taking any medicament. Finally, the dressings were applied on the chronic refractory ulcers of five patients.

RESULTS

After successful surface morphology and cytocompatibility tests, the animal study was carried out. There was a significant difference between starch/extract/4 wt% nZ and other groups on wound size decrement after day 7 (P < 0.05). At the clinical pilot study step, the refractory ulcers of all five patients were healed without any hypersensitivity reaction.

CONCLUSION

Starch-based hydrogel/zeolite dressings may be safe and effective for chronic refractory ulcers.

Nasal delivery of analgesic ketorolac tromethamine thermo- and ion-sensitive in situ hydrogels

Ketorolac tromethamine (KT) was potent to treat moderate to moderately severe pains. However, KT solutions for nasal delivery lost quickly from the nasal route. Thermo- and ion-sensitive in-situ hydrogels (ISGs) are appropriate for nasal drug delivery because the intranasal temperature maintains ∼37 °C and nasal fluids consist of plentiful cations. In this study, a novel nasal thermo- and ion-sensitive ISG of KT was prepared with thermo-sensitive poloxamer 407 (P407) and ion-sensitive deacetylated gellan gum (DGG). The optimal formulation of the KT ISG consisted of 3% (w/v) DGG and 18% (w/v) P407 and its viscosity was up to 7.63 Pas at 37 °C. Furthermore, penetration enhancers and bacterial inhibitors were added and their fractions in the ISG were optimized based on transmucosal efficiencies and toxicity on toad pili. Sulfobutyl ether-β-cyclodextrin of 2.5% (w/v) and chlorobutanol of 0.5% (w/v) were chosen as the penetration enhancer and the bacterial inhibitor, respectively. The Fick's diffusion and dissolution of KT could drive it continuous release from the dually sensitive ISG according to the in vitro investigation. Two methods, writhing frequencies induced by acetic acid and latency time of tails retracting from hot water, were used to evaluate the pharmacodynamics of the KT ISG on the mouse models. The writhing frequencies significantly decreased and the latency time of tail retracting was obviously prolonged (p<0.05) for the KT ISG compared to the control. The thermo- and ion-sensitive KT ISG had appropriate gelation temperature, sustained drug release, improved intranasal absorption, obvious pharmacodynamic effect, and negligible nasal ciliotoxicity. It is a promising intranasal analgesic formulation.

Lidocaine and pain management in the emergency department: a review article

Context:

In the present review, the analgesic effects of lidocaine in acute or chronic painful conditions in the emergency department are discussed. Lidocaine, as a medium-acting local anesthetic with short onset time, is well-recognized, not only as a valuable medication for numerous neuropathic pain conditions, but also for the management of both acute and chronic pain.

Evidence Acquisition:

Research studies related to the different applications of lidocaine in the emergency department were collected from different databases including Cochrane library, Medline (Ovid) and PubMed. The pooled data were categorized, summarized and finally compared.

Results:

Our study revealed that lidocaine is broadly used in various therapeutic approaches for different types of pain, such as visceral/central pain, renal colic etc., in the emergency department.

Conclusions:

The antinociceptive properties of lidocaine are derived from multifaceted mechanisms, turning it into a medication that is safe to administer via different routes which makes it available for use in a variety of medical conditions.