Fabrication of asymmetric nanostarch reinforced Chitosan/PVP membrane and its evaluation as an antibacterial patch for in vivo wound healing application

Naringin and graphene oxide incorporated Moringa oleifera gum/poly(vinyl) alcohol patch for enhanced wound healing

Patients and healthcare systems stand to gain much from the use of substances that can accelerate wound healing. In this research work, a polymeric patch was fabricated using polymers like poly (vinyl alcohol) (PVA) and Moringa oleifera gum (MO) incorporated with graphene oxide (GO) and naringin (Nar) (drug). This study determined the impact of using PVA/MO/GO/Nar polymeric patch on wound healing via in vitro and in vivo investigations. Graphene oxide was synthesized by modified Hummer's method. The synthesized sample was characterized using XRD, FT-IR, RAMAN Spectroscopy, FESEM and HRTEM. Antibacterial analysis of the GO on four different bacteria was studied through well diffusion, colony count, growth curve and biofilm assay. Biocompatibility was analysed by haemolysis assay. The morphology, antibacterial activity, haemolysis assay, swelling, degradation, porosity, water vapour transmission rate, drug release, blood pump model, in-vitro scratch assay and MTT assay were analysed for the fabricated polymeric patches under in-vitro condition. The PVA/MO/GO/Nar patch has shown enhanced wound healing in in-vivo wound healing experiments on albino Wistar rats.

Mycosynthesis of silver nanoparticles from endophytic Aspergillus flavipes AUMC 15772: ovat-statistical optimization, characterization and biological activities

BACKGROUND

Mycosynthesis of silver nanoparticles (SNPs) offers a safe, eco-friendly, and promising alternative technique for large-scale manufacturing. Our study might be the first report that uses mycelial filtrate of an endophytic fungus, Aspergillus flavipes, for SNPs production under optimal conditions as an antimicrobial agent against clinical multidrug-resistant (MDR) wound pathogens.

RESULTS

In the present study, among four different endophytic fungi isolated from leaves of Lycium shawii, the only one isolate that has the ability to mycosynthesize SNPs has been identified for the first time as Aspergillus flavipes AUMC 15772 and deposited in Genebank under the accession number OP521771. One variable at a time (OVAT) and Plackett Burman design (PBD) were conducted for enhancing the production of mycosynthesized SNPs (Myco-SNPs) through optimization using five independent variables. The overall optimal variables for increasing the mycosynthesis of SNPs from mycelial filtrate of A. flavipes as a novel endophytic fungus were a silver nitrate concentration of 2 mM, a pH of 7.0, an incubation time of 5 days, and a mycelial filtrate concentration of 30% in dark conditions. UV-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), X-ray spectroscopy (XRD), Transmission electron microscopy (TEM), and Selected-Area Electron Diffraction (SAED) patterns were used to characterize Myco-SNPs, which showed the peak of absorbance at 420 nm, and FTIR showed the bands at 3426.44, 2923.30, 1681.85, 1552.64, and 1023.02 cm-1, respectively, which illustrated the presence of polyphenols, hydroxyl, alkene, nitro compounds, and aliphatic amines, respectively. The XRD pattern revealed the formation of Myco-SNPs with good crystal quality at 2θ = 34.23° and 38.18°. The TEM image and SAED pattern show the spherical crystalline shape of Myco-SNPs with an average size of 6.9232 nm. High antibacterial activity of Myco-SNPs was recorded against MDR wound pathogens as studied by minimum inhibitory concentrations ranging from 8 to 32 µg/mL, time kill kinetics, and post-agent effects. Also, in vitro cell tests indicated that Myco-SNPs support the cell viability of human skin fibroblast cells as a nontoxic compound.

CONCLUSION

The obtained results revealed the successful production of Myco-SNPs using the mycelial filtrate of A. flavipes, which may be a promising nontoxic alternative candidate for combating MDR wound pathogens.

Asymmetric tri-layer sponge-nanofiber wound dressing containing insulin-like growth factor-1 and multi-walled carbon nanotubes for acceleration of full-thickness wound healing

To more closely resemble the structure of natural skin, multi-layered wound dressings have been developed. Herein, a tri-layer wound dressing was prepared containing a polyacrylamide (PAAm)-Aloe vera (Alo) sponge that had been incorporated with insulin-like growth factor-1 (IGF1) to provide a porous absorbent layer, which was able to promote angiogenesis. Alo nanofibers with multi-walled carbon nanotubes (MWCNT) were electrospun into the bottom layer to increase cell behavior, and a small film of stearic acid was put as a top layer to avoid germy penetration. In comparison to bilayer dressing, the tensile strength increased by 17.0 % (from 0.200 ± 0.010 MPa to 0.234 ± 0.022 MPa) and the elastic modulus by 45.6 % (from 0.217 ± 0.003 MPa to 0.316 ± 0.012 MPa) in the presence of Alo nanofibers containing 0.5 wt% of MWCNT at the bottom layer of Trilayer0.5 dressing. The release profile of IGF1, the antibacterial activity and the degradability of different wound dressings were investigated. Trilayer0.5 indicated the highest cell viability, cell adhesion and angiogenic potential among the prepared dressing materials. In-vivo rat model revealed that the Trilayer0.5 dressing treated group had the highest rate of wound closure and wound healing within 10 days compared to other groups.

Exploring the potential of Rhizopus oryzae AUMC14899 as a novel endophytic fungus for the production of L-tyrosine and its biomedical applications

BACKGROUND

A significant threat to the public's health is the rise in antimicrobial resistance among numerous nosocomial bacterial infections. This may be a detriment to present initiatives to enhance the health of immune-compromised patients. Consequently, attention has been devoted to exploring new bioactive compounds in the field of drug discovery from endophytes. Therefore, this study is the first on the production of L-tyrosine (LT) as a promising bio-therapeutic agent from endophytic fungi.

RESULTS

A new endophytic fungal isolate has been identified for the first time as Rhizopus oryzae AUMC14899 from Opuntia ficus-indica (L.) and submitted to GenBank under the accession number MZ025968. Separation of amino acids in the crude extract of this fungal isolate was carried out, giving a higher content of LT, which is then characterized and purified. LT exhibited strong antibacterial and anti-biofilm activities against multidrug-resistant Gram-negative and Gram-positive bacteria. The recorded minimum inhibitory concentration (MIC) values ranged from 6 to 20 µg/ml. In addition, LT caused a strong reduction in biofilm formation and disrupted the preformed biofilm. Moreover, results indicated that LT supported cell viability, evidencing hemocompatibility and no cytotoxicity.

CONCLUSION

Our findings suggest that LT has potential as a therapeutic agent due to its potential antibacterial, anti-biofilm, hemocompatibility, and lack of cytotoxic activities, which may also increase the range of therapy options for skin burn infections, leading to the development of a novel fungal-based drug.

Recent advances of antibacterial starch-based materials

Starch has attracted a lot of attention because it is biodegradable, renewable, nontoxic and low cost. By adding antibacterial substances to starch, starch-based materials have antibacterial properties. The composite with other materials can improve the comprehensive performance of starch-based materials, thus broadening the application field of the material. In this paper, we focus on antibacterial starch-based materials and review their preparation and applications. It was found that antibacterial starch-based materials were most widely used in packaging, followed by medicine, and the research on smart starch-based materials was relatively less. This review may provide some reference value for subsequent studies of starch-based materials.

Basella alba stem extract integrated poly (vinyl alcohol)/chitosan composite films: A promising bio-material for wound healing

Natural extract-based bio-composite material for wound healing is gaining much attention due to risk of infection and high cost of commercial wound dressing film causes serious problem on the human well-being. Herein, the study outlines the preparation of Poly (vinyl alcohol)/Chitosan/Basella alba stem extract (BAE) based bio-composite film through solvent casting technique and well characterized for wound healing application. Incorporation of BAE into Poly (vinyl alcohol)/Chitosan matrix has shown existence of secondary interactions confirmed by FT-IR analysis. Good morphology, thermal stability and significant improvement in flexibility (∼63.38 %) of the films were confirmed by SEM, TGA and Mechanical test results, respectively. Hydrophilic property (∼9.04 %), water vapor transmission rate (∼70.07 %), swelling ability (∼14.7 %) and degradation rate (∼14.04 %) were enhanced with increase in BAE content. In-vitro studies have shown good antibacterial activity against foremost infectious bacterial strains S. aureus and E. coli. Additionally, BAE integrated Poly (vinyl alcohol)/Chitosan film has amplified anti-inflammatory (∼79.38 %) property, hemocompatibility and excellent biocompatibility (94.9 %) was displayed by cytotoxicity results. Moreover, in-vitro scratch assay and cell adhesion test results illustrated prominent wound healing (96.5 %) and adhesion. Overall results of the present work proclaim that developed bio-composite film could be utilized as a biomaterial in wound care applications.

Honey-Loaded Reinforced Film Based on Bacterial Nanocellulose/Gelatin/Guar Gum as an Effective Antibacterial Wound Dressing

Recently, the use of bacterial nanocellulose (BNC) produced by Acetobacter, which has suitable properties for tissue engineering application as a perfect wound dressing, has attracted considerable attention. For this purpose, we successfully developed honey loaded BNC-reinforced gelatin/dialdehyde-modified guar gum films (H/BNC/Ge/D-GG). Prepared films were studied for their morphological, thermal stability, mechanical, water solubility and degradability properties. The physicochemical properties of the developed films with or without honey loading were studied. The results indicated that by enhancing the honey content of the film, the degradation behavior, adhesion and proliferation of NIH-3T3 fibroblast cells were improved. The films with 15 wt% of honey revealed inhibition activity against S. aureus (13.0±0.1 mm) and E. coli (15.0±1.0 mm) bacteria. Cell culture results demonstrated that the prepared films had good cytocompatibility. Based on the results, the prepared H/BNC/Ge/D-GG films appear to have high potential for antibacterial wound dressings.

Biomechanical Motion-Activated Endogenous Wound Healing through LBL Self-Powered Nanocomposite Repairer with pH-Responsive Anti-Inflammatory Effect

Wound care is still worthy of concern, and effective measures such as electrical stimulating therapy (EST) have sparked compellingly for wound repair. Especially, portable and point-of-care EST devices get extremely desired but these are often limited by inevitable external power sources, lack of biological functions, and mechanical properties conforming to skin tissue. Herein, a dress-on-person self-powered nanocomposite bioactive repairer of wound is designed. As such, the cooperation of the film prepared by layer-by-layer self-assembling 2-hydroxypropyltrimethyl ammonium chloride chitosan (HTCC), alginate (ALG), and poly-dopamine/Fe³⁺ nanoparticles (PFNs), with a self-powered nanogenerator (SN) driven by motion into a nanocomposite repairer (HAP/SN-NR) is conducted. The HAP/SN-NR not only guides cell behavior (proliferation and migration rate ≈61.7%, ≈52.3%), but also facilitates neovascularization (enhanced CD31 expression >4-fold) through its self-powered EST, and the endogenous wound closure with no inflammatory in rats owing to reactive oxygen species (ROS)-clearance of HAP/SN-NR in vitro/vivo through responsively releasing poly-dopamine nanoparticles at wound pH. Enormous efforts illustrate that the repairer is endowed with high self-adhesion to tissue, self-healing, and biodegradation, accelerating wound healing (50% closure ≈5 days). This strategy sheds light on novel multifunctional portable sensor-type dressings and propels the development of intelligent medical devices.

Prospection of chitosan and its derivatives in wound healing: Proof of patent analysis (2010-2020)

Disruption in the normal anatomy and physiology of the skin often leads to wound formation. Its healing is a pretty complex and dynamic biological process with different phases. While there are many biopolymers (and their derivatives) for wound healing purposes. One of the most popular, promising, progressive and attention-grabbing biopolymers is 'chitosan'. It is a polysaccharide biopolymer that has tremendous potential in augmenting the process of wound healing. Most importantly, the derivatives of chitosan have heavily attracted the scientific community's attention to employing them in various formulations for wound healing applications. The prime focus of the present review is to provide scientific and technological prospection about chitosan and its derivatives for wound healing activity, starting from 2010 to 2020. Besides, the review also focuses about toxicity, different formulations and products of chitosan that are currently under clinical trials for wound healing purposes are described. Through this review, we present evidence that abundantly confirms that there is a growing interest in the domain of wound healing using novel, inventive, useful and patent protected chitosan derivatives. We speculate the possibility of more patent protected chitosan derivatives in the future for wound healing applications.

Asymmetric Membranes: A Potential Scaffold for Wound Healing Applications

Currently, due to uprising concerns about wound infections, healing agents have been regarded as one of the major solutions in the treatment of different skin lesions. The usage of temporary barriers can be an effective way to protect wounds or ulcers from dangerous agents and, using these carriers can not only improve the healing process but also they can minimize the scarring and the pain suffered by the human. To cope with this demand, researchers struggled to develop wound dressing agents that could mimic the structural and properties of native skin with the capability to inhibit bacterial growth. Hence, asymmetric membranes that can impair bacterial penetration and avoid exudate accumulation as well as wound dehydration have been introduced. In general, synthetic implants and tissue grafts are expensive, hard to handle (due to their fragile nature and poor mechanical properties) and their production process is very time consuming, while the asymmetric membranes are affordable and their production process is easier than previous epidermal substitutes. Motivated by this, here we will cover different topics, first, the comprehensive research developments of asymmetric membranes are reviewed and second, general properties and different preparation methods of asymmetric membranes are summarized. In the two last parts, the role of chitosan based-asymmetric membranes and electrospun asymmetric membranes in hastening the healing process are mentioned respectively. The aforementioned membranes are inexpensive and possess high antibacterial and satisfactory mechanical properties. It is concluded that, despite the promising current investigations, much effort is still required to be done in asymmetric membranes.

Chitosan Film Containing Mansoa hirsuta Fraction for Wound Healing

Chitosan films entrapped with the Mansoa hirsuta fraction (CMHF) was developed as a new dressing for wound care. The chromatographic profile of the M. hirsuta fraction (MHF) was evaluated by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, and the results showed that MHF is rich in acid triterpenes. Physicochemical characterization of the films prepared using the solvent casting method was performed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetry (TGA), differential scanning calorimetry (DCS), scanning electron microscopy (SEM), atomic force microscopy (AFM), and mechanical properties. CMHF exhibited characteristic bands of both chitosan and MHF, revealing a physical mixture of both. CMHF presented an amorphous nature, thermostability, and dispersion of MHF in the chitosan matrix, resulting in a rough structure. Incorporation of M. hirsuta fraction into chitosan matrix favorably enhanced the mechanical performance and films thickness. The in vivo wound treatment with CMHF for seven days showed a characteristic area of advanced healing, re-epithelization, cell proliferation, and collagen formation. Furthermore, wound closure reached 100% contraction after 10 days of treatment with modulation of interleukins. The incorporation of M. hirsuta fraction into chitosan films was advantageous and showed great potential for stimulating wound repair and regeneration.

Optimality of poly-vinyl alcohol/starch/glycerol/citric acid in wound dressing applicable composite films

This work addresses response surface methodology (RSM) design based investigations to obtain optimality of quaternary formulations [variant macromolecular concentrations of starch (St, 5-10 w/w%), polyvinyl alcohol (PVA, 5-10 w/w%), citric acid (CA, 15-40 wt%) and glycerol (Gl, 15-40 wt%)] associated to wound dressing films. Appropriate combinations of the swelling index (SI), weight loss (WL%) during 27 days, tensile strength (TS) and percentage elongation (%E) have been considered during such studies. The optimized composition was achieved through RSM optimization and exhibited very good water absorption (300.5% SI) and flexibility (87.5%E), and acceptable in-vitro degradation (51.4% WL) and TS (5 MPa) values, which are significantly better than reported data. Further, the film constitution indicated amplified antibacterial effectiveness against both Gram-positive (Listeria monocytogenes) and Gram-negative (Escherichia coli) bacteria and enhanced cell growth (145.5%) to thereby infer upon the potential associated with its application as a viable wound dressing film.

Electrospun asymmetric membranes for wound dressing applications

To accomplish a rapid wound healing it is necessary to develop an asymmetric membrane with interconnected pores consisting of a top layer that prevents rapid dehydration of the wound and bacteria penetration and a sub-layer with high absorption capacity and bactericidal properties. Polycaprolactone (PCL)/polyvinyl acetate (PVAc) asymmetric membranes loaded with the bactericidal monoterpene carvacrol (CRV) were synthesized and characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. Mechanical properties in dry and wet conditions and fluid handling behavior were also assessed. In addition, biological studies regarding their bactericidal effects, cytocompatibility and wound closure properties were also developed. Loading efficiencies of 40-50% were achieved in the prepared samples and 85-100% of the loaded CRV was released in simulated wound pH evolution medium. The significant inhibition of Gram negative (Escherichia coli S17) and Gram positive (Staphylococcus aureus ATCC 25923) bacteria growth clearly showed the suitability of the fabricated membranes for wound healing applications. Furthermore, cytocompatibility of the loaded membranes was demonstrated both in 2D and 3D human dermal fibroblast cultures, as well as cell migration was not impaired by released carvacrol from the membranes. These results highlight the potential of these polymeric electrospun membranes for wound healing.

Silver triethanolamine-loaded PVB/CO films for a potential liquid bandage application

Many studies have reported that silver has excellent antibacterial properties. However, silver ions can easily react with oxygen to form Ag2O, thus leading to a color change and a reduction in its anti-microbial characteristics. In this study, silver triethanolamine- (ST) loaded PVB/CO solution was prepared as a potential candidate liquid bandage. PVB/CO/ST retained high transparency after exposure to light for 12 months, which allowed convenient inspection of the wound bed without removal of the dressing. The PVB/CO/ST film exhibited favorable properties, such as speed of drying, excellent tensile strength and elongation characteristics and water vapor transmission rate (WVTR). It was comfortable and waterproof, and therefore effective at preventing bacterial invasion, providing effective biosafety. PVB/CO/ST solution-treated wounds exhibited accelerated healing and reduced inflammation in a nude mouse mode. Our data suggested that PVB/CO/ST solution could serve as a promising liquid bandage for treatment of minor trauma.

Chitosan based-asymmetric membranes for wound healing: A review

The wound healing process involves highly complex and dynamic events that allow the re-establishment of skin's structural integrity. To further improve or to overcome the drawbacks associated with this process, researchers have been focused on the development of new therapeutics. Among them, asymmetric membranes are currently one of the most promising approaches to be used in wound healing due to its structural similarities with the epidermal and dermal layers of the native skin. The outer layer of asymmetric membranes provides a barrier that protects the wound from external damages (e.g. microorganisms and chemical agents), whereas the interior porous layer acts as template for supporting cell adhesion, migration and proliferation. Among the different materials used to produce these distinct layers, the chitosan arises as one of the preeminent materials due to its inherent biocompatibility, antibacterial, hemostatic, and healing properties. Therefore, in this review, it is provided an overview of the different chitosan-based asymmetric membranes developed for wound dressing applications. Further, the chitosan modifications to enhance its bioactivity as well as the asymmetric membranes general properties and production techniques are also described.

Pharmaceutical Potential of a Novel Chitosan Derivative Schiff Base with Special Reference to Antibacterial, Anti-Biofilm, Antioxidant, Anti-Inflammatory, Hemocompatibility and Cytotoxic Activities

PURPOSE

Chitosan and its derivatives possess several unique properties relevant in the field of pharmaceutics and medicinal chemistry. This study aimed to evaluate the pharmaceutical performance of an innovative chitosan derivative, methyl acrylate chitosan bearing p-nitrobenzaldehyde (MA*CS*pNBA) Schiff base.

METHODS

The antibacterial activity of MA*CS*pNBA was tested against multi-drug resistant (MDR) Gram-negative and Gram-positive bacteria using agar-well diffusion method. Anti-biofilm formation was analyzed using a microtitre plate. Antioxidant assays were performed to assess the scavenging activity of MA*CS*pNBA using DPPH, hydrogen peroxide, superoxide together with its reducing power activity. Anti-inflammatory activity was evaluated by albumin denaturation, membrane stabilization, and proteinase inhibition methods. MA*CS*pNBA was tested for its hemolytic efficiency on human erythrocytes. Cytotoxicity of MA*CS*pNBA was evaluated by MTT assay.

RESULTS

MA*CS*pNBA showed a significant performance as an antibacterial candidate against MDR bacteria, anti-biofilm, antioxidant and anti-inflammatory biomaterial, evidencing hemocompatibility and no cytotoxicity. It exhibited a significant negative correlation with biofilm formation by the MDR-PA-09 strain. Biological activities were found to be significantly concentration-dependent.

CONCLUSIONS

the newly chitosan derivative MA*CS*pNBA showed to be promising for pharmaceutical applications, expanding the treatment ways toward skin burn infections since it allied excellent antibacterial, anti-biofilm, antioxidant, anti-inflammatory, hemocompatibility and absence of cytotoxic activities.