Evaluation of wound healing potential of β-chitin hydrogel/nano zinc oxide composite bandage

Hydrogels based on seafood chitin: From extraction to the development

Chitin is extensively applied in vast applications due to its excellent biological properties, such as biodegradable and non-toxic. About 50 % of waste generated during seafood processing is chitin. Conventionally, chitin is extracted via chemical method. However, it has many shortcomings. Many novel extraction methods have emerged, including enzymatic hydrolysis, microbial fermentation, ultrasonic or microwave-assisted, ionic liquids, and deep eutectic solvents. Chitin and its derivatives-based hydrogels have attracted much attention due to their excellent properties. Nevertheless, they all have many limitations. Therefore, the preparation and application of chitin and its derivatives-based hydrogels are still facing great challenges. This review focuses on the challenges and prospects for sustainable chitin extraction from seafood waste and the preparation and application of chitin and its derivatives-based hydrogels. First section summarizes the mechanism and application of several methods of extracting chitin. The different extraction methods were evaluated from the aspects of yield, degree of acetylation, and protein and mineral residuals. The shortcomings of the extraction methods are also discussed. Next section summarizes the preparation and application of chitin and its derivatives-based hydrogels. Overall, we hope this mini-review can provide a practical reference for selecting chitin extraction methods from seafood and applying chitin and its derivatives-based hydrogels.

Synthesis, characterization, and antiparasitic effects of zinc oxide nanoparticles-eugenol nanosuspension against Toxoplasma gondii infection

Background

In this study, zinc oxide nanoparticles-coated with eugenol (ZnO@Eug) were synthesized and evaluated as a nanosuspension (NSus) formulation against Toxoplasma gondii in vitro and in vivo.

Methods

An anti-Toxoplasma activity assay for ZnO@Eug NSus was conducted in vitro, ex vivo, and in vivo. FTIR spectroscopy confirmed the formation of ZnO@Eug NSus by detecting several functional groups involved; EDX and SEM demonstrated the grain of ZnO-NPs embedded with Eug and compositional purity.

Results

Surface charge (ZP) and size distribution (DLS) of ZnO@Eug NSus were determined to be -22.7 mV and 109.6 nm, respectively. According to the release kinetics, approximately 60% of the ZnO-NPs and Eug were released in the first 45 min. In the cytotoxicity assay, ZnO-NPs, Eug, and ZnO@Eug NSus had IC50 values of 71.85, 22.39, and 2.02 mg/mL, respectively. The therapeutic efficacy of ZnO@Eug against T. gondii was 56.3%, which was not significantly different from that of spiramycin (58.9%) (Positive-control). The tissue tachyzoites in the liver, spleen, and peritoneum were less than 50% in groups treated with Eug, spiramycin, and ZnO@Eug NSus compared to the control. ZnO@Eug-treated groups showed a survival rate of up to 13 days.

Conclusions

The ZnO@Eug NSus demonstrated antiparasitic activity against T. gondii with minimal toxic effects and high efficiency in increasing the survival of infected mice. The nanoformulations of ZnO-NPs incorporated with Eug could, in the future, be considered for treating toxoplasmosis in humans and animals if a detailed study was conducted to determine the precise dose and measure side effects.

Antimicrobial Nano-Zinc Oxide Biocomposites for Wound Healing Applications: A Review

Chronic wounds are a major concern for global health, affecting millions of individuals worldwide. As their occurrence is correlated with age and age-related comorbidities, their incidence in the population is set to increase in the forthcoming years. This burden is further worsened by the rise of antimicrobial resistance (AMR), which causes wound infections that are increasingly hard to treat with current antibiotics. Antimicrobial bionanocomposites are an emerging class of materials that combine the biocompatibility and tissue-mimicking properties of biomacromolecules with the antimicrobial activity of metal or metal oxide nanoparticles. Among these nanostructured agents, zinc oxide (ZnO) is one of the most promising for its microbicidal effects and its anti-inflammatory properties, and as a source of essential zinc ions. This review analyses the most recent developments in the field of nano-ZnO–bionanocomposite (nZnO-BNC) materials—mainly in the form of films, but also hydrogel or electrospun bandages—from the different preparation techniques to their properties and antibacterial and wound-healing performances. The effect of nanostructured ZnO on the mechanical, water and gas barrier, swelling, optical, thermal, water affinity, and drug-release properties are examined and linked to the preparation methods. Antimicrobial assays over a wide range of bacterial strains are extensively surveyed, and wound-healing studies are finally considered to provide a comprehensive assessment framework. While early results are promising, a systematic and standardised testing procedure for the comparison of antibacterial properties is still lacking, partly because of a not-yet fully understood antimicrobial mechanism. This work, therefore, allowed, on one hand, the determination of the best strategies for the design, engineering, and application of n-ZnO-BNC, and, on the other hand, the identification of the current challenges and opportunities for future research.

Facile fabrication of chitin/ZnO composite hydrogels for infected wound healing

When ordinary wounds are infected, the skin's self-healing capacity declines; thus appropriate dressings with both antibacterial ability and healing ability for bacteria-associated wounds are indispensable. In this work, multifunctional chitin/ZnO composite hydrogels have been designed as an infected full-thickness skin wound-healing material. The hydrogels are fabricated by a facile one-pot strategy through the sequential addition of commercial ZnO powders into aqueous alkaline chitin solutions, crosslinking and regeneration. The regenerated nanoscale ZnO particles aggregate into microscale particles and are embedded in the chitin matrix with tight interactions, including hydrogen bonding and coordination interactions. The decoration of ZnO endows the chitin/ZnO composite hydrogels with excellent antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with acceptable biocompatibility. More importantly, the chitin/ZnO composite hydrogels show an outstanding accelerated infectious full-thickness wound-healing performance with more fibroblast proliferation, more collagen deposition, and more neogenesis of the epithelium and granulation tissue. Therefore, it is expected that the chitin/ZnO composite hydrogels can serve as competitive skin wound dressings for the prevention and control of infections.

Smart piezoelectric biomaterials for tissue engineering and regenerative medicine: a review

Due to the presence of electric fields and piezoelectricity in various living tissues, piezoelectric materials have been incorporated into biomedical applications especially for tissue regeneration. The piezoelectric scaffolds can perfectly mimic the environment of natural tissues. The ability of scaffolds which have been made from piezoelectric materials in promoting cell proliferation and regeneration of damaged tissues has encouraged researchers in biomedical areas to work on various piezoelectric materials for fabricating tissue engineering scaffolds. In this review article, the way that cells of different tissues like cardio, bone, cartilage, bladder, nerve, skin, tendon, and ligament respond to electric fields and the mechanism of tissue regeneration with the help of piezoelectric effect will be discussed. Furthermore, all of the piezoelectric materials are not suitable for biomedical applications even if they have high piezoelectricity since other properties such as biocompatibility are vital. Seen in this light, the proper piezoelectric materials which are approved for biomedical applications are mentioned. Totally, the present review introduces the recent materials and technologies that have been used for tissue engineering besides the role of electric fields in living tissues.

ZnO nanostructured materials and their potential applications: progress, challenges and perspectives

Extensive research in nanotechnology has been conducted to investigate new behaviours and properties of materials with nanoscale dimensions. ZnO NPs owing to their distinct physical and chemical properties have gained considerable importance and are hence investigated to a detailed degree for exploitation of these properties. This communication, at the outset, elaborates the various chemical methods of preparation of ZnO NPs, viz., the mechanochemical process, controlled precipitation, sol-gel method, vapour transport method, solvothermal and hydrothermal methods, and methods using emulsion and micro-emulsion environments. The paper further describes the green methods employing the use of plant extracts, in particular, for the synthesis of ZnO NPs. The modifications of ZnO with organic (carboxylic acid, silanes) and inorganic (metal oxides) compounds and polymer matrices have then been described. The multitudinous applications of ZnO NPs across a variety of fields such as the rubber industry, pharmaceutical industry, cosmetics, textile industry, opto-electronics and agriculture have been presented. Elaborative narratives on the photocatalytic and a variety of biomedical applications of ZnO have also been included. The ecotoxic impacts of ZnO NPs have additionally been briefly highlighted. Finally, efforts have been made to examine the current challenges and future scope of the synthetic modes and applications of ZnO NPs.

Wound healing properties of green (using Lawsonia inermis leaf extract) and chemically synthesized ZnO nanoparticles in albino rats

Wound healing is one of the utmost medical issues in human and veterinary medicine, which explains the urgent need for developing new agents that possess wound healing activities. The present study aimed to assess the effectiveness of green and chemical zinc oxide nanoparticles (ZnO-NPs) for wound healing. ZnO-NPs (green using Lawsonia inermis leaf extract and chemical) were synthesized and characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and high-resolution transmission electron microscopy (HRTEM). The gels containing the nanomaterials were prepared and inspected. Forty-five albino rats were divided into three groups, the control group was treated with normal saline 0.9%, and the other two groups were treated with gels containing green or chemical ZnO-NPs, respectively. On the 3^rd, 7^th, 14^th, and 21^st days post-treatment (PT), the wounds were clinicopathologically examined. Both nanomaterials have good crystallinity and high purity, but green ZnO-NPs have a longer nanowire length and diameter than chemical ZnO-NPs. The formed gels were highly viscous with a pH of 6.5 to 7. The treated groups with ZnO-NP gels showed clinical improvement, as decreased wound surface area (WSA) percent (WSA%), increased wound contraction percent (WC%), and reduced healing time (p < 0.05) when compared with the control group. The histological scoring showed that the epithelialization score was significantly higher at the 21^st day post-treatment in the treated groups than in the control group (p < 0.05), but the vasculature, necrosis, connective tissue formation, and collagen synthesis scores were mostly similar. The green and chemical ZnO-NP gels showed promising wound healing properties; however, the L. inermis-mediated ZnO-NPs were more effective.

Nanomaterials-based drug delivery approaches for wound healing

Abstract:

Wound healing is a complex and dynamic process that requires intricate synchronization between multiple cell types within appropriate extracellular microenvironment. Wound healing process involves four overlapping phases in a precisely regulated manner, consisting of hemostasis, inflammation, proliferation, and maturation. For an effective wound healing all four phases must follow in a sequential pattern within a time frame. Several factors might interfere with one or more of these phases in healing process, thus causing improper or impaired wound healing resulting in non-healing chronic wounds. The complications associated with chronic non-healing wounds, along with the limitations of existing wound therapies, have led to the development and emergence of novel and innovative therapeutic interventions. Nanotechnology presents unique and alternative approaches to accelerate the healing of chronic wounds by the interaction of nanomaterials during different phases of wound healing. This review focuses on recent innovative nanotechnology-based strategies for wound healing and tissue regeneration based on nanomaterials, including nanoparticles, nanocomposites and scaffolds. The efficacy of the intrinsic therapeutic potential of nanomaterials (including silver, gold, zinc oxide, copper, cerium oxide, etc.) and the ability of nanomaterials as carriers (liposomes, hydrogels, polymeric nanomaterials, nanofibers) as therapeutic agents associated with wound-healing applications have also been addressed. The significance of these nanomaterial-based therapeutic interventions for wound healing needs to be highlighted to engage researchers and clinicians towards this new and exciting area of bio-nanoscience. We believe that these recent developments will offer researchers an updated source on the use of nanomaterials as an advanced approach to improve wound healing.

Advances in the Sensing and Treatment of Wound Biofilms

Wound biofilms represent a particularly challenging problem in modern medicine. They are increasingly antibiotic resistant and can prevent the healing of chronic wounds. However, current treatment and diagnostic options are hampered by the complexity of the biofilm environment. In this review, we present new chemical avenues in biofilm sensors and new materials to treat wound biofilms, offering promise for better detection, chemical specificity, and biocompatibility. We briefly discuss existing methods for biofilm detection and focus on novel, sensor-based approaches that show promise for early, accurate detection of biofilm formation on wound sites and that can be translated to point-of-care settings. We then discuss technologies inspired by new materials for efficient biofilm eradication. We focus on ultrasound-induced microbubbles and nanomaterials that can both penetrate the biofilm and simultaneously carry active antimicrobials and discuss the benefits of those approaches in comparison to conventional methods.

Cationic, anionic and neutral polysaccharides for skin tissue engineering and wound healing applications

Today, chronic wound care and management can be regarded as a clinically critical issue. However, the limitations of current approaches for wound healing have encouraged researchers and physicians to develop more efficient alternative approaches. Advances in tissue engineering and regenerative medicine have resulted in the development of promising approaches that can accelerate wound healing and improve the skin regeneration rate and quality. The design and fabrication of scaffolds that can address the multifactorial nature of chronic wound occurrence and provide support for the healing process can be considered an important area requiring improvement. In this regard, polysaccharide-based scaffolds have distinctive properties such as biocompatibility, biodegradability, high water retention capacity and nontoxicity, making them ideal for wound healing applications. Their tunable structure and networked morphology could facilitate a number of functions, such as controlling their diffusion, maintaining wound moisture, absorbing a large amount of exudates and facilitating gas exchange. In this review, the wound healing process and the influential factors, structure and properties of carbohydrate polymers, physical and chemical crosslinking of polysaccharides, scaffold fabrication techniques, and the use of polysaccharide-based scaffolds in skin tissue engineering and wound healing applications are discussed.

Advances in the Sensing and Treatment of Wound Biofilms

Wound biofilms represent a particularly challenging problem in modern medicine. They are increasingly antibiotic resistant and can prevent the healing of chronic wounds. However, current treatment and diagnostic options are hampered by the complexity of the biofilm environment. In this review, we present new chemical avenues in biofilm sensors and new materials to treat wound biofilms, offering promise for better detection, chemical specificity, and biocompatibility. We briefly discuss existing methods for biofilm detection and focus on novel, sensor‐based approaches that show promise for early, accurate detection of biofilm formation on wound sites and that can be translated to point‐of‐care settings. We then discuss technologies inspired by new materials for efficient biofilm eradication. We focus on ultrasound‐induced microbubbles and nanomaterials that can both penetrate the biofilm and simultaneously carry active antimicrobials and discuss the benefits of those approaches in comparison to conventional methods.

Whey Proteins-Zinc Oxide Bionanocomposite as Antibacterial Films

The use of toxic crosslinking agents and reagents in the fabrication of hydrogels is a frequent issue which is particularly concerning for biomedical or food packaging applications. In this study, novel antibacterial bionanocomposite films were obtained through a simple solvent casting technique without using any crosslinking substance. Films were made from a flexible and transparent whey protein matrix containing zinc oxide nanoparticles synthesised via a wet chemical precipitation route. The physicochemical and functional properties of the ZnO nanoparticles and of the composite films were characterised, and their antibacterial activity was tested against S. epidermidis and E. coli. The synthesised ZnO nanoparticles had an average size of about 30 nm and a specific surface area of 49.5 m2/g. The swelling ratio of the bionanocomposite films increased at basic pH, which is an appealing feature in relation to the absorption of chronic wound exudate. A n-ZnO concentration-dependent antibacterial effect was observed for composite films. In particular, marked antibacterial activity was observed against S. epidermidis. Overall, these findings suggest that this novel material can be a promising and sustainable alternative in the design of advanced solutions for wound dressing or food packaging.

Development of membranes based on carboxymethyl cellulose/acetylated arrowroot starch containing bromelain extract carried on nanoparticles and liposomes

Polymeric membranes have been used in several applications, including their use as curatives in cutaneous wounds. Bromelain has long been used for anti-inflammatory purposes, so the objective of this work was to produce carboxymethylcellulose-acetylated blends, incorporate bromelain, characterize the systems, compare the blends with bromelain loaded in nanoparticles and liposomes and, finally, to evaluate their healing potential. Four membrane formulations were produced by solvent evaporation: the control, membranes containing free bromelain, bromelain-loaded nanoparticles (NPs) and bromelain-loaded liposomes (LIPs). The enzyme concentration was the same for all formulations. Transparent, flexible and intact films were obtained. The membranes containing free bromelain, bromelain-loaded NPs and bromelain-loaded LIPs had higher water content, lower water vapor permeability and maximum tensile strength, and greater elongation at rupture. The capacity to absorb simulated exudate was higher in samples containing free bromelain, and bioadhesion was reduced in the presence of free bromelain compared to the control. An in vivo assay was performed to verify the membranes' healing potential. Histological analysis revealed no edema on the 14th day in animals treated with membranes containing bromelain-loaded NPs and LIPs.

Nanomaterials Versus The Microbial Compounds With Wound Healing Property

Age and diabetes related slow-healing or chronic wounds may result in morbidity and mortality through persistent biofilms infections and prolonged inflammatory phase. Nano-materials [metal/metal oxide NPs (39%), lipid vehicles (21%), polymer NPs (19%), ceramic nanoparticles (NPs) (14%), and carbon nanomaterials (NMs) (7%)] can be introduced as a possible next-generation therapy because of either their intrinsic wound healing activity or via carrying bioactive compounds including, antibiotics, antioxidants, growth factor or stem cell. The nanomaterials have been shown to implicate in all four stages of wound healing including hemostasis (polymer NPs, ceramic NPs, nanoceria-6.1%), inflammation (liposome/vesicles/solid lipid NPs/polymer NPs/ceramic NPs/silver NPs/gold NPs/nanoceria/fullerenes/carbon-based NPs-32.7%), proliferation (vesicles/liposome/solid lipid NPs/gold NPs/silver NPs/iron oxide NPs/ceramic NPs/copper NPs/self-assembling elastin-like NPs/nanoceria/micelle/dendrimers/polymer NPs-57.1%), remodeling (iron oxide NPs/nanoceria-4.1%). Natural compounds from alkaloids, flavonoids, retinoids, volatile oil, terpenes, carotenoids, or polyphenolic compounds with proven antioxidant, anti-inflammatory, immunomodulatory, or antimicrobial characteristics are also well known for their potential to accelerate the wound healing process. In the current paper, we survey the potential and properties of nanomaterials and microbial compounds in improving the process of wound and scar healing. Finally, we review the potential biocompounds for incorporation to nano-material in perspective to designate more effective or multivalent wound healing natural or nano-based drugs.

Potential Applications of Nanomaterials and Technology for Diabetic Wound Healing

Diabetic wound shows delayed and incomplete healing processes, which in turn exposes patients to an environment with a high risk of infection. This article has summarized current developments of nanoparticles/hydrogels and nanotechnology used for promoting the wound healing process in either diabetic animal models or patients with diabetes mellitus. These nanoparticles/hydrogels promote diabetic wound healing by loading bioactive molecules (such as growth factors, genes, proteins/peptides, stem cells/exosomes, etc.) and non-bioactive substances (metal ions, oxygen, nitric oxide, etc.). Among them, smart hydrogels (a very promising method for loading many types of bioactive components) are currently favored by researchers. In addition, nanoparticles/hydrogels can be combined with some technology (including PTT, LBL self-assembly technique and 3D-printing technology) to treat diabetic wound repair. By reviewing the recent literatures, we also proposed new strategies for improving multifunctional treatment of diabetic wounds in the future.

Nanotechnology-driven advances in the treatment of diabetic wounds

Diabetic foot ulcers (DFUs) are chronic severe complications of diabetes disease and remain a worldwide clinical challenge with social and economic consequences. Diabetic wounds can cause infection, amputation of lower extremities, and even death. Several factors including impaired angiogenesis, vascular insufficiency, and bacterial infections result in a delayed process of wound healing in diabetic patients. Treatment of wound infections using traditional antibiotics has become a critical status. Thus, finding new therapeutic strategies to manage diabetic wounds is urgently needed. Nanotechnology has emerged as an efficient approach for this purpose. This review aimed to summarize recent advances using nanotechnology for the treatment of diabetic wounds.

Biologically-synthesised ZnO/CuO/Ag nanocomposite using propolis extract and coated on the gauze for wound healing applications

Wound healing has long been recognised as a major clinical challenge for which stablishing more effective wound therapies is necessary. The generation of metallic nanocomposites using biological compounds is emerging as a new promising strategy for this purpose. In this study, four metallic nanoparticles (NPs) with propolis extract (Ext) and one without propolis including ZnO/Ext, ZnO/Ag/Ext, ZnO/CuO/Ext, ZnO/Ag/CuO/Ext and ZnO/W were prepared by microwave method and assessed for their wound healing activity on excision experimental model of wounds in rats. The developed nanocomposites have been characterised by physico-chemical methods such as X-ray diffraction, scanning electron microscopy, diffuse reflectance UV-vis spectroscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and Brunauer-Emmett-Teller analyses. The wounded animals treated with the NPs/Ext in five groups for 18 days. Every 6 days, for measuring wound closure rate, three samples of each group were examined for histopathological analysis. The prepared tissue sections were investigated by haematoxylin and Eosin stainings for the formation of epidermis, dermis and muscular and Masson's trichrome staining for the formation of collagen fibres. These findings toughly support the probability of using this new ZnO/Ag/Ext materials dressing for a wound care performance with significant effect compared to other NPs.

Bioactive antibacterial bilayer PCL/gelatin nanofibrous scaffold promotes full-thickness wound healing

Treatment of diabetic, chronic, and full-thickness wounds is a challenge as these injuries usually lead to infections that cause delayed and inappropriate healing. Therefore, fabrication of skin scaffolds with prolonged antibacterial properties are of great interest. Due to this demand, bilayered nanofibrous scaffolds were fabricated based on polycaprolactone and gelatin. The top layer of these scaffolds contained amoxicillin as a model drug and the bottom layer was loaded with zinc oxide nanoparticles to accelerate wound healing. Several characterization techniques including FTIR, SEM, swelling, tensile test, in vitro degradation, drug release, antibacterial activity, and MTT assay were used to assess physical, mechanical, and biological properties of produced nanofibers. SEM results demonstrated that bilayered scaffolds have smooth bead-free microstructures while in vitro release test showed that samples have a sustained release for amoxicillin up to 144 h (tested time). Disk diffusion assessment confirmed the potency of scaffolds for hindering bacterial growth while results of cytotoxicity evaluation revealed that scaffolds could effectively accelerate cell proliferation. Finally, in vivo tests on full-thickness rat models revealed that fabricated nanofibers accelerate wound contraction, increase collagen deposition and angiogenesis, and prevent scar formation. Altogether, results showed that fabricated scaffolds are promising candidates for treatment of full-thickness wounds.

Hyaluronic Acid (HA)-Based Silk Fibroin/Zinc Oxide Core-Shell Electrospun Dressing for Burn Wound Management

Burn injuries represent a major life-threatening event that impacts the quality of life of patients, and places enormous demands on the global healthcare systems. This study introduces the fabrication and characterization of a novel wound dressing made of core-shell hyaluronic acid-silk fibroin/zinc oxide (ZO) nanofibers for treatment of burn injuries. The core-shell configuration enables loading ZO-an antibacterial agent-in the core of nanofibers, which in return improves the sustained release of the drug and maintains its bioactivity. Successful formation of core-shell nanofibers and loading of zinc oxide are confirmed by transmission electron microscopy, Fourier-transform infrared spectroscopy, and energy dispersive X-ray. The antibacterial activity of the dressings are examined against Escherichia coli and Staphylococcus aureus and it is shown that addition of ZO improves the antibacterial property of the dressing in a dose-dependent fashion. However, in vitro cytotoxicity studies show that high concentration of ZO (>3 wt%) is toxic to the cells. In vivo studies indicate that the wound dressings loaded with ZO (3 wt%) substantially improves the wound healing procedure and significantly reduces the inflammatory response at the wound site. Overall, the dressing introduced herein holds great promise for the management of burn injuries.

In situ Fabrication of Nano ZnO/BCM Biocomposite Based on MA Modified Bacterial Cellulose Membrane for Antibacterial and Wound Healing

Background

Developing an ideal wound dressing that meets the multiple demands of safe and practical, good biocompatibility, superior mechanical property and excellent antibacterial activity is highly desirable for wound healing. Bacterial cellulose (BC) is one of such promising class of biopolymers since it can control wound exudates and can provide moist environment to a wound resulting in better wound healing. However, the lack of antibacterial activity has limited its application.

Methods and Results

We prepared a flexible dressing based on a bacterial cellulose membrane and then modified it by chemical crosslinking to prepare in situ synthesis of nZnO/BCM via a facile and eco-friendly approach. Scanning electron microscopy (SEM) results indicated that nZnO/BCM membranes were characterized by an ideal porous structure (pore size: 30~ 90 μm), forming a unique string-beaded morphology. The average water vapor transmission of nZnO/BCM was 2856.60 g/m²/day, which improved the moist environment of nZnO/BCM. ATR-FITR further confirmed the stepwise deposition of nano-zinc oxide. Tensile testing indicated that our nanocomposites were flexible, comfortable and resilient. Bacterial suspension assay and plate counting methods demonstrated that 5wt. % nZnO/BCM possessed excellent antibacterial activity against S.aureus and E. coli, while MTT assay demonstrated that they had no measurable cytotoxicity toward mammalian cells. Moreover, skin irritation test and histocompatibility examination supported that 5wt. % nZnO/BCM had no stimulation to skin and had acceptable biocompatibility with little infiltration of the inflammatory cells. Finally, by using a bacteria-infected (S. aureus and E. coli) murine wound model, we found that nZnO/BCM could prevent in vivo bacterial infections and promote wound healing via accelerating the re-epithelialization and wound contraction, and these membranes had no obvious toxicity toward normal tissues.

Conclusion

Therefore, the constructed nZnO/BCM has great potential for biomedical applications as an efficient antibacterial wound dressing.

A brief overview on nano-sized materials used in the topical treatment of skin and soft tissue bacterial infections

Introduction: Skin and soft tissue infections are a significant clinical problem that can happen anywhere on the body. Bacteria are the most common cause of skin and soft tissue infections in humans. Despite the fact that there is a lot of antimicrobial agents and antibiotics for elucidating bacterial infections, the prevention and control of infectious diseases continue to be one of the greatest challenges for public health worldwide. At the present time, an alarming increase in multidrug resistance instantly requests to find suitable alternatives to current antibiotics. Therefore, drug resistance has been attempted to be resolved by the development of new classes of antimicrobial agents or targeted delivery systems for antibacterial drugs using nanotechnology.Area covered: The present review summarizes the emerging topical efforts to support the use of nano-sized materials as a new opportunity to combat today's skin infectious diseases.Expert opinion: Nano-sized materials can overcome the stratum corneum barrier and deliver drugs specifically to bacterial skin infections with trivial side effects. Depending on the physicochemical characteristics of nano-scaled materials, they can specifically be selected to target bacterial pathogens and also to get into the skin layers. These systems can overcome the antibiotic-resistance mechanisms and help us to the design of novel topical formulations that will make administration of antibacterial compounds safer, easier and more convenient.

Biomass-Derived Dialdehyde Cellulose Cross-linked Chitosan-Based Nanocomposite Hydrogel with Phytosynthesized Zinc Oxide Nanoparticles for Enhanced Curcumin Delivery and Bioactivity

A sustainable biomass-based nanocomposite hydrogel was formulated, characterized, and applied for curcumin delivery. Phytosynthesized zinc oxide nanoparticles (ZnO NPs) employing musk melon (Cucumis melo) seed extract was embedded in the hydrogel matrices and cross-linked using Dialdehyde cellulose prepared from sugarcane (Saccharum officinarum) bagasse (SCB). Nanoparticle incorporation enhanced the hydrogel's swelling degree to 4048% at pH 4.0. Also, an improved tensile strength of 14.1 ± 0.32 MPa was exhibited by the nanocomposite hydrogel compared to 9.79 ± 0.76 MPa for the pure chitosan cellulose hydrogel. A curcumin loading efficiency of 89.68% with around 30% increased loading was exhibited for the nanocomposite hydrogel. A Fickian diffusion-controlled curcumin release mechanism with maximum release at pH 7.4 was obtained. The synergistic effect on the antimicrobial activity was exhibited against Staphylococcus aureus and Trichophyton rubrum. The in vitro cytotoxicity studies employing L929 cells and A431 cells demonstrated good biocompatibility and enhanced anticancer activity of the curcumin-loaded green nanocomposite hydrogel compared to pure curcumin.

Preparation of α-chitin-based nanocomposite as an effective biocatalyst for microwave aided domino reaction

In this paper, chitin (Ch) was extracted by an optimized method from cuttlebone of the Persian Gulf cuttlefish (Sepiidae, Cephalopoda). The extracted chitin was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD) and thermal gravimetric analysis (TGA) which showed that the extracted chitin was in alpha form. The degree of N-acetylation (DA) and degree of substitution (DS) of α-chitin were calculated using titration method and FTIR spectroscopy and found to be 80-82% and 19.57 respectively. The α-Chitin was used as biomolecules for the preparation of nanostructured Ch/ZnO via a hydrothermal method. The obtained nanocomposite was characterized using FT-IR, XRD, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) analysis. The antimicrobial aspect of Ch/ZnO nanocomposite was previously proposed. In this paper, attempt was made to add the catalytic feature to these traits. For this purpose, the nanostructured Ch/ZnO was used as reusable nanocatalyst in the green and efficient synthesis of Benzo[a]pyrano(2,3-c)phenazine derivatives thru a four components microwave aided domino reaction. Eco-friendly, easy work up and separation of the nanostructured catalyst are some of the highlighted features this protocol.

ZnO-NPs embedded biodegradable thiolated bandage for postoperative surgical site infection: In vitro and in vivo evaluation

Post-operative surgical site infections (SSI) present a serious threat and may lead to complications. Currently available dressings for SSI lack mucoadhesion, safety, efficacy and most importantly patient compliance. We aimed to address these concerns by developing a bioactive thiolated chitosan-alginate bandage embedded with zinc oxide nanoparticles (ZnO-NPs) for localized topical treatment of SSI. The FTIR, XRD, DSC and TGA of bandage confirmed the compatibility of ingredients and modifications made. The porosity, swelling index and lysozyme degradation showed good properties for wound healing and biodegradation. Moreover, in-vitro antibacterial activity showed higher bactericidal effect as compared to ZnO-NPs free bandage. In-vivo wound healing in murine model showed significant improved tissue generation and speedy wound healing as compared to positive and negative controls. Over all, thiolated bandage showed potential as an advanced therapeutic agent for treating surgical site infections, meeting the required features of an ideal surgical dressing.

Electrospun polycaprolactone/hydroxyapatite/ZnO nanofibers as potential biomaterials for bone tissue regeneration

Fabricating a bioartificial bone graft possessing structural, mechanical and biological properties mimicking the real bone matrix is a major challenge in bone tissue engineering. Moreover, the developed materials are prone to microbial invasion leading to biomaterial centered infections which might limit their clinical translation. In the present study, biomimetic nanofibrous scaffolds of Poly ɛ-caprolactone (PCL)/nano-hydroxyapatite (nHA) were electrospun with 1wt%, 5wt%, 10wt%, 15wt% and 30wt% of zinc oxide (ZnO) nanoparticles in order to understand the optimal concentration range of (ZnO) nanoparticles balancing both biocompatibility and osteoregeneration. The developed nanofibrous scaffolds were successfully characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDAX), contact angle, fourier transform infrared spectroscopy (FTIR), wide-angle X-Ray diffraction (WAXD), brunaueremmett Teller (BET) surface area and tensile testing. Biocompatibility of the developed scaffolds at in vitro level was evaluated by culturing MG-63 cells and investigating the impact on cell viability, proliferation, protein adsorption, alkaline phosphatase (ALP) activity and biomineralization. The PCL/nHA scaffolds exhibited a 1.2-fold increase in cell viability and proliferation, while incorporation of ZnO nanoparticles to PCL/nHA imparted antimicrobial activity to the scaffolds with a progressive increase in the antimicrobial efficacy with increasing ZnO concentration. The results of cell viability were supported by ALP activity and mineralization assay, wherein, PCL/nHA/ZnO scaffolds showed higher ALP activity and better mineralization capacity as compared to pristine PCL. Although, the PCL/nHA/ZnO scaffolds with 10, 15 and 30wt% of ZnO particles exhibited superior antimicrobial efficacy against both gram-negative (E. coli) and gram-positive (S. aureus) bacteria, a significant decrease in the cell viability and mechanical properties was observed at higher concentrations of ZnO namely 15 and 30%. Amongst the various ZnO concentrations studied optimal cell viability, antimicrobial effect and mechanical strength were observed at 10wt.% ZnO concentration. Thus, the present study revealed that the biomimetic tri-component PCL/nHA/ZnO scaffolds with ZnO concentration range of ≤ 10% could be ideal for achieving optimal biocompatibility (cell proliferation, biomineralization, and antimicrobial capacity) and mechanical stability thus making it a promising biomaterial substrate for bone tissue regeneration.

Aspects of Nanomaterials in Wound Healing

Wound infections impose a remarkable clinical challenge that has a considerable influence on morbidity and mortality of patients, influencing the cost of treatment. The unprecedented advancements in molecular biology have come up with new molecular and cellular targets that can be successfully applied to develop smarter therapeutics against diversified categories of wounds such as acute and chronic wounds. However, nanotechnology-based diagnostics and treatments have achieved a new horizon in the arena of wound care due to its ability to deliver a plethora of therapeutics into the target site, and to target the complexity of the normal wound-healing process, cell type specificity, and plethora of regulating molecules as well as pathophysiology of chronic wounds. The emerging concepts of nanobiomaterials such as nanoparticles, nanoemulsion, nanofibrous scaffolds, graphene-based nanocomposites, etc., and nano-sized biomaterials like peptides/proteins, DNA/RNA, oligosaccharides have a vast application in the arena of wound care. Multi-functional, unique nano-wound care formulations have acquired major attention by facilitating the wound healing process. In this review, emphasis has been given to different types of nanomaterials used in external wound healing (chronic cutaneous wound healing); the concepts of basic mechanisms of wound healing process and the promising strategies that can help in the field of wound management.

Defective Black Nano-Titania Thermogels for Cutaneous Tumor-Induced Therapy and Healing

Current challenges in cutaneous tumor therapy are healing the skin wounds resulting from surgical resection and eliminating possible residual tumor cells to prevent recurrence. To address this issue, bifunctional biomaterials equipped with effective tumor therapeutic capacity for skin cancers and simultaneous tissue regenerative ability for wound closure are highly recommended. Herein, we report an injectable thermosensitive hydrogel (named BT-CTS thermogel) with the integration of nanosized black titania (B-TiO_{2- x}, ∼50 nm) nanoparticles into a chitosan (CTS) matrix. The B-TiO_{2- x} nanocrystal exhibits a crystalline/amorphous core-shell structure with abundant oxygen vacancies, which endows the BT-CTS thermogels with simultaneous photothermal therapy (PTT) and photodynamic therapy (PDT) effects under single-wavelength near-infrared laser irradiation, leading to an excellent therapeutic effect on skin tumors in vitro and in vivo. Moreover, the BT-CTS thermogel not only supports the adhesion, proliferation, and migration of normal skin cells but also facilitates skin tissue regeneration in a murine chronic wound model. Therefore, such BT-CTS thermogels with easy injectability, excellent thermostability, and simultaneous PTT and PDT efficacy as well as tissue regenerative activity offers a promising pathway for the healing of cutaneous tumor-induced wounds.

Recent Advances in Biomaterials Science and Engineering Research in India: A Minireview

Biomedical research in health innovation and product development encompasses convergent technologies that primarily integrate biomaterials science and engineering at its core. Particularly, research in this area is instrumental for the implementation of biomedical devices (BMDs) that offer innovative solutions to help maintain and improve quality of life of patients worldwide. Despite achieving extraordinary success, implantable BMDs are still confronted with complex engineering and biological challenges that need to addressed for augmenting device performance and prolonging lifetime in vivo. Biofabrication of tissue constructs, designing novel biomaterials and employing rational biomaterial design approaches, surface engineering of implants, point of care diagnostics and micro/nano-based biosensors, smart drug delivery systems, and noninvasive imaging methodologies are among strategies exploited for improving clinical performance of implantable BMDs. In India, advances in biomedical technologies have dramatically advanced health care over the last few decades and the country is well-positioned to identify opportunities and translate emerging solutions. In this article, we attempt to capture the recent advances in biomedical research and development progressing across the country and highlight the significant research work accomplished in the areas of biomaterials science and engineering.

Chitosan based metallic nanocomposite scaffolds as antimicrobial wound dressings

Chitosan based nanocomposite scaffolds have attracted wider applications in medicine, in the area of drug delivery, tissue engineering and wound healing. Chitosan matrix incorporated with nanometallic components has immense potential in the area of wound dressings due to its antimicrobial properties. This review focuses on the different combinations of Chitosan metal nanocomposites such as Chitosan/nAg, Chitosan/nAu, Chitosan/nCu, Chitosan/nZnO and Chitosan/nTiO2 towards enhancement of healing or infection control with special reference to the antimicrobial mechanism of action and toxicity.

Evaluation of propylene glycol nanoliposomes containing curcumin on burn wound model in rat: biocompatibility, wound healing, and anti-bacterial effects

Curcumin is an effective wound healing agent in burn therapy, but due to its low bioavailability, it is required to be formulated for topical therapy. Liposomal nanocarriers are developed as stable and efficient dermal delivery systems. In this study, we prepared curcumin-propylene glycol liposomes (Cur-PgL) to treat animals subjected to second degree burns. The characterization tests confirmed the production of monodisperse nanoliposomes of average size of about 145 nm with high entrapment efficiency percentage and a sustained release behavior. TEM analysis of nanocarriers showed no aggregation in long time storage up to 60 days. The biocompatibility of the Cur-PgL formulation was evaluated by ISO standards. We found that Cur-PgL 0.3% was the effective dose in injured rats without any side effects on intact skin. The cytotoxicity of the Cur-PgL 0.3% nanovesicles was also assessed on human dermal fibroblast (HDF) cells. The results showed no detectable cytotoxicity, but considerable cytotoxicity was observed in higher concentration of 1.5 and 3 mg/ml of free and PgL forms of curcumin. Eight days of application of Cur-PgL on burned rats resulted in a significant (P<0.001) recovery of wound repair parameters, and after 18 days, wound contraction occurred significantly (P < 0.001) compared to the other groups. The antibacterial activity of the Cur-PgL formulation was found to be similar to the silver sulfadiazine (SSD) cream 1% regarding the inhibition of the bacterial growth. In conclusion, the low dose of curcumin nanoliposomal formulation efficiently improved injuries and infections of burn wounds and it can be considered in burn therapy.

Electrospinning and wound healing activity of β-chitin extracted from cuttlefish bone

A nanofibrous β-chitin web was fabricated via electrospinning for use as a novel wound dressing material. β-chitin was extracted from cuttlefish bone using deproteinization and demineralization. First, cuttlefish bone was alkali-treated to remove the proteins and was then treated with the acid for demineralization. The extracted β-chitin was dissolved in formic acid as solvent to evaluate its electrospinnability, and the electrospinnability increased remarkably when β-chitin was blended with poly(ethylene oxide) (PEO) than without. The blended β-chitin/PEO nanofibers had a fiber diameter of about 400 nm, and the diameter decreased after soaking in water to remove the PEO. The structural and physical properties of the β-chitin material and its nanofibers were characterized using Attenuated total reflectance infrared spectroscopy (ATR-IR), Proton nuclear magnetic resonance (¹H NMR), Scanning electron microscopy/Energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), texturometry, viscometry and contact angle measurements, and an animal test was conducted to investigate the wound healing effect. The β-chitin nanofibers were found to have great potential as nanomaterials for wound healing.

Bioactive polymeric formulations for wound healing

Ricinoleic acid (RA) has potential to promote wound healing because of its analgesic and anti-inflammatory properties. This study investigates the synthesis and characterization of RA liposomes infused in a hydrogel for topical application. Lecithin liposomes containing RA were prepared and incorporated into a chitosan solution and were subsequently cross-linked with dialdehyde β-cyclodextrin (Di-β-CD). Chitosan/Di-β-CD concentrations and reaction temperatures were varied to alter gelation time, water content, and mechanical properties of the hydrogel in an effort to obtain a wide range of RA release profiles. Hydrogel cross-linking was confirmed by spectroscopy, and liposome and carrier hydrogel morphology via microscopy. Chitosan, Di-β-CD, and liposome concentrations within the formulation affected the extent of matrix swelling, mechanical strength, and pore and overall morphology. Higher cross-linking density of the hydrogel led to lower water uptake and slower release rate of RA. Optimized formulations resulted in a burst release of RA followed by a steady release pattern accounting for 80% of the encapsulated RA over a period of 48 hours. However, RA concentrations above 0.1 mg/mL were found to be cytotoxic to fibroblast cultures in vitro because of the oily nature of RA. These formulations promoted wound healing when used to treat full thickness skin wounds (2 cm²) in Wister male rats. The wound contraction rates were significantly higher compared to a commercially available topical cream after a time period of 21 days. Histopathological analysis of the RA-liposomal chitosan hydrogel group showed that the epidermis, dermis, and subcutaneous skin layers displayed an accelerated yet normal healing compared to control group.

ZnO nanoparticle-embedded silk fibroin–polyvinyl alcohol composite film: a potential dressing material for infected wounds

A highly effective composite film based on ZnO NPs, silk fibroin and PVA for an infected wound.

Recent Advances in Antimicrobial Hydrogels Containing Metal Ions and Metals/Metal Oxide Nanoparticles

Recently, the rapid emergence of antibiotic-resistant pathogens has caused a serious health problem. Scientists respond to the threat by developing new antimicrobial materials to prevent or control infections caused by these pathogens. Polymer-based nanocomposite hydrogels are versatile materials as an alternative to conventional antimicrobial agents. Cross-linking of polymeric materials by metal ions or the combination of polymeric hydrogels with nanoparticles (metals and metal oxide) is a simple and effective approach for obtaining a multicomponent system with diverse functionalities. Several metals and metal oxides such as silver (Ag), gold (Au), zinc oxide (ZnO), copper oxide (CuO), titanium dioxide (TiO₂) and magnesium oxide (MgO) have been loaded into hydrogels for antimicrobial applications. The incorporation of metals and metal oxide nanoparticles into hydrogels not only enhances the antimicrobial activity of hydrogels, but also improve their mechanical characteristics. Herein, we summarize recent advances in hydrogels containing metal ions, metals and metal oxide nanoparticles with potential antimicrobial properties.