Nano-silver functionalized polysaccharides as a platform for wound dressings: A review

MIL-88-NH2(Fe) conjugated pectin through a post-modification Ugi four-component reaction: A robust bio-based catalyst for the synthesis of cyclic carbonate via CO2 fixation reaction

The functionalization of materials via multicomponent reactions (MCRs) led to a recent surge in the interest of researchers, owing to the creation of exceptional properties in materials. Herein, a novel robust porous catalyst was prepared via the conjugation of MIL-88-NH2(Fe) and pectin (DAP/MIL-88-NH2(Fe)) through the post-modification Ugi four-component reaction (Ugi-4CR) for the first time. To achieve this aim, pectin was oxidized using sodium periodate as an oxidant agent to produce dialdehyde pectin (DAP). Next, the generated carbonyl functional groups participated in the Ugi-4CR of MIL-88-NH2(Fe), 4-methyl carboxylic acid, and cyclohexyl (c-hex) isocyanide to produce DAP/MIL-88-NH2(Fe) catalyst. The catalytic activity of the prepared bio-based catalyst was examined in producing cyclic carbonates through the chemical fixation of CO2 with epoxides in the presence of TBAB as a co-catalyst. Interestingly, catalytic experiments revealed that the prepared bio-based catalyst could be remarkably active regarding the CO2 fixation reaction and performed it in the shortest reaction time (1 h) via high CO2 adsorbent capacity. The outstanding benefits of the prepared bio-based catalyst include its non-hazardous nature, inexpensive, green and gentle reaction conditions, and ability to be reusable in several runs with slight loss of catalytic activity due to a more durable framework with high chemical and thermal stability.

Synergistic Antimicrobial Glycyrrhizic Acid-Based Functional Biosensing Composite for Sensitive Glucose Monitoring and Collaborative Wound Healing

High glucose blood and bacterial infection remain major issues for the slow healing of diabetic wounds, so developing functional biosensing composite with excellent antibacterial and remarkable glucose response sensitivity is necessary and prospective. Herein, by in situ synthesis AgNPs on the surface of self-prepared PTIGA elastomers, PTIGA-AgNPs conductive composites are obtained with efficient synergistic antibacterial effect, excellent mechanical and self-healing properties. The strain of the composites can reach 1800%, and its self-healing efficiency exceeds 90% at 60 °C within 8 h. Both elastomers and composites represent excellent biocompatibility and the antibacterial rate against E. coli and S. aureus exceeded 90%. Moreover, the biosensor assembled from the conductive composites exhibits excellent glucose response sensitivity and stability, with a sensitivity coefficient of 0.518 mA mm-1 in the range of 0.2-3.6 × 10-3 m glucose concentration, as well as a low detection limit of 0.08 × 10-3 m. Furthermore, based on the remarkable antibacterial performance and bioactivity derived from GA, the composites reduce the expression of pro-inflammatory factors and promote the production of anti-inflammatory factors, and effectively promote the regeneration of skin and granulation tissue of wounds in a diabetic full-thickness skin defect model, demonstrating the enormous therapeutic potential in diabetic wound healing.

Antibiotic delivery in the presence of green AgNPs using multifunctional bilayer carrageenan nanofiber/sodium alginate nanohydrogel for rapid control of wound infections

This study constructed bilayer nano-hydrogels using solvent casting and electrospinning techniques. The first layer consisted of a hydrogel containing sodium alginate and gellan gum, while the second layer was a carrageenan/polyvinyl alcohol nanofibrous membrane. The nanohydrogels were prepared with different doses of doxycycline antibiotic (0.12, 0.06, 0.03 g) and a fixed amount of silver nanoparticles (0.012 g), which were synthesized using the green method including Capparis spinosa leaf extract. The films were tested for their mechanical properties, swelling behavior, XRD, and FTIR, and their morphology was characterized using SEM. The biological properties of the nanohydrogels were also extensively assayed. X-ray diffraction analysis showed peak 111 for silver nanoparticles. Incorporating silver nanoparticles significantly enhanced nanohydrogels' mechanical and antibacterial properties and improved their ability to heal wounds. Nanohydrogels exhibited biodegradability, biocompatibility, anti-inflammatory properties (57.63 %), and high cell viability (>85 %) in laboratory conditions. The study confirmed that wound dressings containing doxycycline with controlled release are highly effective against pathogenic bacteria and prevent the formation of biofilms (92 %). The rats in-vivo study demonstrated that 100 % wound closure was achieved in nanohydrogels containing SA/GG/PVA/CAR/AgNPs/DOX0.12 after 14 days. The films could potentially lead to the development of new treatments against bacterial infections and inflammatory conditions of wounds.

Characterization of a polysaccharide from Amauroderma rugosum and its proangiogenic activities in vitro and in vivo

Amauroderma rugosum (AR), also known as "Blood Lingzhi" in Chinese, is a basidiomycete belonging to the Ganodermataceae family. Four polysaccharide fractions were systematically isolated and purified from AR. Subsequently, their compositions were examined and analyzed via high-performance gel permeation chromatography (HPGPC), analysis of the monosaccharide composition, Fourier-transform infrared spectroscopy (FT-IR), and 1H nuclear magnetic resonance (NMR). The zebrafish model was then used to screen for proangiogenic activities of polysaccharides by inducing vascular insufficiency with VEGF receptor tyrosine kinase inhibitor II (VRI). The third fraction of AR polysaccharides (PAR-3) demonstrated the most pronounced proangiogenic effects, effectively ameliorating VRI-induced intersegmental vessel deficiency in zebrafish. Concurrently, the mRNA expression levels of vascular endothelial growth factor (VEGF)-A and VEGF receptors were upregulated by PAR-3. Moreover, the proliferation, migration, invasion, and tube formation of human umbilical vein endothelial cells (HUVECs) were also stimulated by PAR-3, consistently demonstrating that PAR-3 possesses favorable proangiogenic properties. The activation of the Akt, ERK1/2, p38 MAPK, and FAK was most likely the underlying mechanism. In conclusion, this study establishes that PAR-3 isolated from Amauroderma rugosum exhibits potential as a bioresource for promoting angiogenesis.

Modified in-vitro AATCC-100 procedure to measure viable bacteria from wound dressings

Chronic wounds are reoccurring healthcare problems in the United States and cost up to $50 billion annually. Improper wound care results in complications such as wound debridement, surgical amputation, and increased morbidity/ mortality due to opportunistic infections. To eliminate wound infections, many antimicrobial dressings are developed and submitted to FDA for evaluation. AATCC-100 is a standard method widely used to evaluate cloth wound dressings. This method, requires enrichment, followed by culturing to measure the concentration of culturable organisms; a caveat to this method could result in neglected viable but nonculturable (VBNC) bacteria and overestimate the antimicrobial properties of wound dressings. Therefore, the objectives of this study were to assess this accepted protocol with quantitative real-time polymerase chain reaction (qRT-PCR), to measure time dependent antimicrobial efficacy of wound dressing, and to examine for potential viable bacteria but non-culturable as compared with traditional plating methods. The test organisms included opportunistic pathogens: Pseudomonas aeruginosa (ATCC 15692) and Staphylococcus aureus (ATCC 43300). To mimic a wound dressing environment, samples of commercially available wound dressings (McKesson Inc.) with silver ion (positive control) and dressings without silver ion (positive control) were assessed under sterile conditions. All samples were examined by the original protocol (the extended AATCC-100 method) and qRT-PCR. The expression of specific housekeeping genes was measured (proC for P. aeruginosa and 16s rRNA for S. aureus). Based on these tests, log reduction of experimental conditions was compared to identify time dependent and precise antimicrobial properties from wound dressing samples. These results showed antimicrobial properties of wound dressings diminished as incubation days are increased for both methods from day 1 PCR result of 4.31 ± 0.54 and day 1 plating result of 6.31 ± 3.04 to day 3 PCR result of 1.22 ± 0.97 and day 3 plating result of 5.89 ± 2.41. These results show that data from qRT-PCR generally produced lower standard deviation than that of culture methods, hence shown to be more precise. Complementary parallel analysis of samples using both methods better characterized antimicrobial properties of the tested samples.

Antimicrobial, Antioxidant, and Anti-Inflammatory Nanoplatform for Effective Management of Infected Wounds

Burn wound healing continues to pose significant challenges due to excessive inflammation, the risk of infection, and impaired tissue regeneration. In this regard, an antibacterial, antioxidant, and anti-inflammatory nanocomposite (called HPA) that combines a nanosystem using hexachlorocyclotriphosphazene and the natural polyphenol of Phloretin with silver nanoparticles (AgNPs) is developed. HPA effectively disperses AgNPs to mitigate any toxicity caused by aggregation while also showing the pharmacological activities of Phloretin. During the initial stage of wound healing, HPA rapidly releases silver ions from its surface to suppress bacterial activity. Moreover, these nanoparticles are pH-sensitive and degrade efficiently in the acidic infection microenvironment, gradually releasing Phloretin. This sustained release of Phloretin helps scavenge overexpressed reactive oxygen species in the infected microenvironment area, thus reducing the upregulation of pro-inflammatory cytokines. The antibacterial activity, free radical clearance, and regulation of inflammatory factors of HPA through in vitro experiments are validated. Additionally, its effects using an infectious burn mouse model in vivo are evaluated. HPA is found to promote collagen deposition and epithelialization in the wound area. With its synergistic antibacterial, antioxidant, and anti-inflammatory activities, as well as favorable biocompatibilities, HPA shows great promise as a safe and effective multifunctional nanoplatform for burn injury wound dressings.

Nanotechnology development in surgical applications: recent trends and developments

This paper gives a detailed analysis of nanotechnology's rising involvement in numerous surgical fields. We investigate the use of nanotechnology in orthopedic surgery, neurosurgery, plastic surgery, surgical oncology, heart surgery, vascular surgery, ophthalmic surgery, thoracic surgery, and minimally invasive surgery. The paper details how nanotechnology helps with arthroplasty, chondrogenesis, tissue regeneration, wound healing, and more. It also discusses the employment of nanomaterials in implant surfaces, bone grafting, and breast implants, among other things. The article also explores various nanotechnology uses, including stem cell-incorporated nano scaffolds, nano-surgery, hemostasis, nerve healing, nanorobots, and diagnostic applications. The ethical and safety implications of using nanotechnology in surgery are also addressed. The future possibilities of nanotechnology are investigated, pointing to a possible route for improved patient outcomes. The essay finishes with a comment on nanotechnology's transformational influence in surgical applications and its promise for future breakthroughs.

Cellulose-Based Metallogels-Part 3: Multifunctional Materials

The incorporation of the metal phase into cellulose hydrogels, resulting in the formation of metallogels, greatly expands their application potential by introducing new functionalities and improving their performance in various fields. The unique antiviral, antibacterial, antifungal, and anticancer properties of metal and metal oxide nanoparticles (Ag, Au, Cu, CuxOy, ZnO, Al2O3, TiO2, etc.), coupled with the biocompatibility of cellulose, allow the development of composite hydrogels with multifunctional therapeutic potential. These materials can serve as efficient carriers for controlled drug delivery, targeting specific cells or pathogens, as well as for the design of artificial tissues or wound and burn dressings. Cellulose-based metallogels can be used in the food packaging industry to provide biodegradable and biocidal materials to extend the shelf life of the goods. Metal and bimetallic nanoparticles (Au, Cu, Ni, AuAg, and AuPt) can catalyze chemical reactions, enabling composite cellulose hydrogels to be used as efficient catalysts in organic synthesis. In addition, metal-loaded hydrogels (with ZnO, TiO2, Ag, and Fe3O4 nanoparticles) can exhibit enhanced adsorption capacities for pollutants, such as dyes, heavy metal ions, and pharmaceuticals, making them valuable materials for water purification and environmental remediation. Magnetic properties imparted to metallogels by iron oxides (Fe2O3 and Fe3O4) simplify the wastewater treatment process, making it more cost-effective and environmentally friendly. The conductivity of metallogels due to Ag, TiO2, ZnO, and Al2O3 is useful for the design of various sensors. The integration of metal nanoparticles also allows the development of responsive materials, where changes in metal properties can be exploited for stimuli-responsive applications, such as controlled release systems. Overall, the introduction of metal phases augments the functionality of cellulose hydrogels, expanding their versatility for diverse applications across a broad spectrum of industries not envisaged during the initial research stages.

Encapsulation of Sericin-Decorated Efficient Agents in Silk Hydrogels for Wound Dressings

Excessive oxidative stress, bacterial infections, and inflammation are the primary factors impeding the healing of skin wounds. Bioactive hydrogels are commonly employed in the treatment of skin injuries. However, the limited solubility of many drugs and active agents in water significantly hampers their effectiveness in hydrogel dressings. In this research, prior to incorporation into the silk fibroin (SF) hydrogel matrix, two active agents curcumin and silver nanoparticles (Ag NPs) were decorated by silk sericin to improve their dispersibility and stability in water. The resultant SF/Ag/C hydrogels combined the biological safety and nontoxicity of SF, the antioxidant and anti-inflammatory efficacy of curcumin, and the antibacterial effect of Ag NPs. These properties effectively enhanced wound repair by reducing bacterial infections, mitigating oxidative stress, suppressing the expression of pro-inflammatory factors, and promoting angiogenesis. This study presented a straightforward approach for constructing bioactive hydrogels for the promotion of the wound healing process.

Green Synthesis of Magnetic Supramolecules β-Cyclodextrin/Iron Oxide Nanoparticles for Photocatalytic and Antibacterial Applications

Iron oxide nanoparticles (Fe3O4NPs) are a fascinating field of study due to their wide range of practical applications in environmental and medical contexts. This study presents a straightforward, environmentally friendly method for producing Fe3O4NPs utilizing β-cyclodextrin (β-CD) as a reducing and capping agent. This approach results in the rapid and effective eco-friendly synthesis of β-CD/Fe3O4NPs. The properties and characteristics of β-CD/Fe3O4NPs were investigated using various methods, including ultraviolet-visible (UV/vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetry analysis (TGA), and vibrating-sample magnetometry (VSM). The absorption of β-CD/Fe3O4NPs caused a distinct peak at 349 nm, as evidenced by the results of UV/vis studies. This peak was attributed to the absorption of surface plasmon resonance. The crystalline nature of β-CD/Fe3O4NPs was confirmed through XRD analysis. The SEM and TEM analyses have verified the geometry and structural characteristics of β-CD/Fe3O4NPs. The β-CD/Fe3O4NPs exhibited remarkable effectiveness in the decomposing efficiency (%) of methylene blue (MB) dye with 52.2, 94.1, and 100% for 0.2, 0.4, and 0.6 g β-CD/Fe3O4NPs, respectively. In addition, the highest efficiency in hunting radicals was observed (347.2 ± 8.2 mg/g) at 100 mg/mL β-CD/Fe3O4NPs; the combination of β-CD/Fe3O4NPs exhibited remarkable effectiveness in inhibiting the growth of some bacteria that cause infections. The capabilities of β-CD/Fe3O4NPs for various applications showed that these materials could be used in photocatalytic, antioxidants, and antibacterial. Additionally, the eco-friendly synthesis of these materials makes them a promising option for the remediation of harmful pollutants and microbes.

Curcumin-stabilized silver nanoparticles encapsulated in biocompatible electrospun nanofibrous scaffold for sustained eradication of drug-resistant bacteria

Due to the misuse of antibiotics, the emerging drug-resistance of pathogenic microbes has aroused considerable concerns for the public health, which demands the continuous search for safe and efficient antimicrobial treatment. In this study, curcumin reduced and stabilized silver nanoparticles (C-Ag NPs) were successfully encapsulated into electrospun nanofiber membranes consisted of polyvinyl alcohol (PVA) cross-linked by citric acids (CA), which exhibited desirable biocompatibility and broad-spectrum antimicrobial activities. The homogeneously distributed and sustained release of C-Ag NPs in the constructed nanofibrous scaffolds yield prominent killing effect against Escherichia coli, Staphylococcus aureus and Methicillin-resistant Staphylococcus aureus (MRSA), which involved the reactive oxygen species (ROS) generation. Outstanding elimination of bacterial biofilms and excellent antifungal activity against Candida albicans was also identified after treated with PVA/CA/C-Ag. Transcriptomic analysis on MRSA treated by PVA/CA/C-Ag revealed the antibacterial process is related to disrupting carbohydrate and energy metabolism, as well as destroying bacterial membranes. Significant down-regulation of the expression of multidrug-resistant efflux pump gene sdrM was observed pointing to the role of PVA/CA/C-Ag to overcome the bacterial resistance. Therefore, the constructed ecofriendly and biocompatible nanofibrous scaffolds provide a robust and versatile nanoplatform of reversal potential to eradicate drug-resistant pathogenic microbe in environmental as well as healthcare applications.

Antibacterial 3D-Printed Silver Nanoparticle/Poly Lactic-Co-Glycolic Acid (PLGA) Scaffolds for Bone Tissue Engineering

Infectious bone defects present a major challenge in the clinical setting currently. In order to address this issue, it is imperative to explore the development of bone tissue engineering scaffolds that are equipped with both antibacterial and bone regenerative capabilities. In this study, we fabricated antibacterial scaffolds using a silver nanoparticle/poly lactic-co-glycolic acid (AgNP/PLGA) material via a direct ink writing (DIW) 3D printing technique. The scaffolds' microstructure, mechanical properties, and biological attributes were rigorously assessed to determine their fitness for repairing bone defects. The surface pores of the AgNPs/PLGA scaffolds were uniform, and the AgNPs were evenly distributed within the scaffolds, as confirmed via scanning electron microscopy (SEM). Tensile testing confirmed that the addition of AgNPs enhanced the mechanical strength of the scaffolds. The release curves of the silver ions confirmed that the AgNPs/PLGA scaffolds released them continuously after an initial burst. The growth of hydroxyapatite (HAP) was characterized via SEM and X-ray diffraction (XRD). The results showed that HAP was deposited on the scaffolds, and also confirmed that the scaffolds had mixed with the AgNPs. All scaffolds containing AgNPs exhibited antibacterial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). A cytotoxicity assay using mouse embryo osteoblast precursor cells (MC3T3-E1) showed that the scaffolds had excellent biocompatibility and could be used for repairing bone tissue. The study shows that the AgNPs/PLGA scaffolds have exceptional mechanical properties and biocompatibility, effectively inhibiting the growth of S. aureus and E. coli. These results demonstrate the potential application of 3D-printed AgNPs/PLGA scaffolds in bone tissue engineering.

Advances in Functional Hydrogel Wound Dressings: A Review

One of the most advanced, promising, and commercially viable research issues in the world of hydrogel dressing is gaining functionality to achieve improved therapeutic impact or even intelligent wound repair. In addition to the merits of ordinary hydrogel dressings, functional hydrogel dressings can adjust their chemical/physical properties to satisfy different wound types, carry out the corresponding reactions to actively create a healing environment conducive to wound repair, and can also control drug release to provide a long-lasting benefit. Although a lot of in-depth research has been conducted over the last few decades, very few studies have been properly summarized. In order to give researchers a basic blueprint for designing functional hydrogel dressings and to motivate them to develop ever-more intelligent wound dressings, we summarized the development of functional hydrogel dressings in recent years, as well as the current situation and future trends, in light of their preparation mechanisms and functional effects.

Optical, structural and antibacterial properties of silver nanoparticles and DNA-templated silver nanoclusters

Silver nanoparticles (AgNPs) are increasingly considered for biomedical applications as drug-delivery carriers, imaging probes and antibacterial agents. Silver nanoclusters (AgNCs) represent another subclass of nanoscale silver. AgNCs are a promising tool for nanomedicine due to their small size, structural homogeneity, antibacterial activity and fluorescence, which arises from their molecule-like electron configurations. The template-assisted synthesis of AgNCs relies on organic molecules that act as polydentate ligands. In particular, single-stranded nucleic acids reproducibly scaffold AgNCs to provide fluorescent, biocompatible materials that are incorporable in other formulations. This mini review outlines the design and characterization of AgNPs and DNA-templated AgNCs, discusses factors that affect their physicochemical and biological properties, and highlights applications of these materials as antibacterial agents and biosensors.

Electrospun Nanofibers Loaded with Plantago major L. Extract for Potential Use in Cutaneous Wound Healing

Plantago major L. is a plant available worldwide that has been traditionally used for several medical applications due to its wound healing, anti-inflammatory, and antimicrobial properties. This work aimed to develop and evaluate a nanostructured PCL electrospun dressing with P. major extract encapsulated in nanofibers for applications in wound healing. The extract from leaves was obtained by extraction in a mixture of water:ethanol = 1:1. The freeze-dried extract presented a minimum inhibitory concentration (MIC) for Staphylococcus Aureus susceptible and resistant to methicillin of 5.3 mg/mL, a high antioxidant capacity, but a low content of total flavonoids. Electrospun mats without defects were successfully produced using two P. major extract concentrations based on the MIC value. The extract incorporation in PCL nanofibers was confirmed using FTIR and contact angle measurements. The PCL/P. major extract was evaluated using DSC and TGA demonstrating that the incorporation of the extract decreases the thermal stability of the mats as well as the degree of crystallinity of PCL-based fibers. The P. major extract incorporation on electrospun mats produced a significant swelling degree (more than 400%) and increased the capacity of adsorbing wound exudates and moisture, important characteristics for skin healing. The extract-controlled release evaluated using in vitro study in PBS (pH, 7.4) shows that the P. major extract delivery from the mats occurs in the first 24 h, demonstrating their potential capacity to be used in wound healing.

Applications of MXene and its modified materials in skin wound repair

The rapid healing and repair of skin wounds has been receiving much clinical attention. Covering the wound with wound dressing to promote wound healing is currently the main treatment for skin wound repair. However, the performance of wound dressing prepared by a single material is limited and cannot meet the requirements of complex conditions for wound healing. MXene is a new two-dimensional material with electrical conductivity, antibacterial and photothermal properties and other physical and biological properties, which has a wide range of applications in the field of biomedicine. Based on the pathophysiological process of wound healing and the properties of ideal wound dressing, this review will introduce the preparation and modification methods of MXene, systematically summarize and review the application status and mechanism of MXene in skin wound healing, and provide guidance for subsequent researchers to further apply MXene in the design of skin wound dressing.

A collagen-based theranostic wound dressing with visual, long-lasting infection detection capability

Continuous wound monitoring is one strategy to minimise infection severity and inform prompt variations in therapeutic care following infection diagnosis. However, integration of this functionality in therapeutic wound dressings is still challenging. We hypothesised that a theranostic dressing could be realised by integrating a collagen-based wound contact layer with previously demonstrated wound healing capability, and a halochromic dye, i.e. bromothymol blue (BTB), undergoing colour change following infection-associated pH changes (pH: 5-6 ➔ >7). Two different BTB integration strategies, i.e. electrospinning and drop-casting, were pursued to introduce long-lasting visual infection detection capability through retention of BTB within the dressing. Both systems had an average BTB loading efficiency of 99 wt% and displayed a colour change within 1 min of contact with simulated wound fluid. Drop-cast samples retained up to 85 wt% of BTB after 96 h in a near-infected wound environment, in contrast to the fibre-bearing prototypes, which released over 80 wt% of BTB over the same time period. An increase in collagen denaturation temperature (DSC) and red shifts (ATR-FTIR) suggest the formation of secondary interactions between the collagen-based hydrogel and the BTB, which are attributed to count for the long-lasting dye confinement and durable dressing colour change. Given the high L929 fibroblast viability in drop-cast sample extracts (92 %, 7 days), the presented multiscale design is simple, cell- and regulatory-friendly, and compliant with industrial scale-up. This design, therefore, offers a new platform for the development of theranostic dressings enabling accelerated wound healing and prompt infection diagnosis.

Substance P&dimethyloxallyl glycine-loaded carboxymethyl chitosan/gelatin hydrogel for wound healing

Recent efforts have focused on preparing drug-loaded hydrogel for wound healing. In order to obtain an ideal hydrogel dressing for skin wound repair, a carboxymethyl chitosan-gelatin hydrogel was prepared for co-delivery of SP (substance P) and DMOG (dimethyloxallyl glycine) by a chemical cross-linking method using genipin as the cross-linking agent. The synthesized hydrogels have good biocompatibility and physicochemical properties due to the low toxicity of the hydrogel material. The three-dimensional network structure of the hydrogels supports cell migration and proliferation, and the combination of SP and DMOG drugs exhibited strong effects on cell proliferation. Moreover, the co-loaded drug hydrogels could significantly promote wound healing in vivo, and provide a potential hydrogel for wound healing.

Mild Heat-Assisted Polydopamine/Alginate Hydrogel Containing Low-Dose Nanoselenium for Facilitating Infected Wound Healing

In clinical practice, it has become urgent to develop multifunctional wound dressings that can combat infection and prompt wound healing simultaneously. In this study, we proposed a polydopamine/alginate/nanoselenium composite hydrogel (Alg-PDA-Se) for the treatment of infected wounds. In particular, polydopamine endows the composite hydrogel with controllable near-infrared photothermal properties, while low-dosage selenium nanoparticles (Se NPs) offer excellent anti-oxidation, anti-inflammatory, pro-proliferative, pro-migration, and pro-angiogenic performances, which are verified by multiple cells, including macrophages, fibroblasts, and endothelial cells. More interestingly, the combination of mild temperature with low-dosage Se NPs produces a synergistic effect on combating both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) and promoting the healing of bacteria-infected wounds in vivo. We anticipate that the designed composite hydrogel might be a potential candidate for anti-infection bioactive dressing.

Antibacterial quaternary ammonium chitosan/carboxymethyl starch/alginate sponges with enhanced hemostatic property for the prevention of dry socket

Tooth extraction commonly leads to postoperative wound bleeding, bacterial infection, and even the occurrence of dry socket. Therefore, developing a biomedical material with favorable antibacterial and excellent hemostatic properties to prevent the post-extraction dry socket is necessary. Herein, quaternary ammonium chitosan/ carboxymethyl starch/alginate (ACQ) sponges are developed via Ca²⁺ cross-linking, electrostatic interaction, and lyophilization methods. The results show that the bio-multifunctional sponges exhibit interconnected porous structures with significant fluid absorption rates and suitable water vapor transmission rates. In vitro cellular and hemolysis experiments indicate that the developed sponges have acceptable biocompatibility. Notably, the constructed sponges effectively inhibit the growth of E. coli, S. aureus, and C. albicans, as well as achieve rapid hemostasis in the mouse liver injury and mini-pig tooth extraction models by absorbing blood and promoting red blood cell adhesion. Thus, the created bio-multifunctional sponges show tremendous promise as a hemostatic material for wound management after tooth extraction.

Self-Standing Bioinspired Polymer Films Doped with Ultrafine Silver Nanoparticles as Innovative Antimicrobial Material

Thin self-standing films with potential antimicrobial synergistic activity have been produced by a simple green chemical synthesis with overnight thermal treatment. Their properties have been studied by scanning electron microscopy, X-ray photoelectron spectroscopy and other techniques to understand their potential range of applications. In this work, the focus was set on the development of a potential novel and effective alternative to conventional antimicrobial materials. By creating an antimicrobial polymer blend, and using it to develop and immobilize fine (~25 nm) silver nanophases, we further aimed to exploit its film-forming properties and create a solid composite material. The resulting polymer matrix showed improved water uptake percentage and better stability in the presence of water. Moreover, the antimicrobial activity of the films, which is due to both organic and inorganic components, has been evaluated by Kirby-Bauer assay against common foodborne pathogens (Staphylococcus aureus and Salmonella enterica) and resulted in a clear inhibition zone of 1.2 cm for the most complex nanocomposition. The excellent performance against bacteria of fresh and 6-month-old samples proves the prospects of this material for the development of smart and biodegradable food packaging applications.

Antibacterial coaxial hydro-membranes accelerate diabetic wound healing by tuning surface immunomodulatory functions

Diabetic foot ulcers, typical non-healing wounds, represent a severe clinical problem. Advanced glycation end-products (AGEs), which create a prolonged pro-inflammatory micro-environment in defective sites, can be responsible for refractoriness of these ulcers. Macrophages are polarized to the M2 phenotype to facilitate the transition from a pro-inflammatory microenvironment to an anti-inflammatory microenvironment, which has been demonstrated to be an effective way to accelerate diabetic wound closure. Herein, we developed coaxial hydro-membranes mimicking the extracellular matrix structure that are capable of anti-inflammatory and antibacterial functions for diabetic wound repair. These fibrous membranes maintain a moist microenvironment to support cell proliferation. Macrophages grow in an elongated shape on the surface of the fibrous membranes. The fibrous membranes effectively impaired macrophage AGE-induced M1 polarization and induced macrophage polarization towards the M2 phenotype. The effects of the fibrous membranes on the interactions between macrophages and repair cells under a diabetic condition were also investigated. Furthermore, in vivo results from a full-thickness diabetic wound model confirmed the potential of the coaxial hydro-membranes to accelerate wound healing. This study's results indicate that the developed bioactive anti-inflammatory and antibacterial wound dressing can affect AGE-induced macrophage activation and crosstalk between macrophages and fibroblasts for treating diabetic wounds.

Multifunctional Mesoporous Silica Nanoparticles Reinforced Silk Fibroin Composite with Antibacterial and Osteogenic Effects for Infectious Bone Rehabilitation

BACKGROUND

Existing implant materials cannot meet the essential multifunctional requirements of repairing infected bone defects, such as antibacterial and osteogenesis abilities. A promising strategy to develop a versatile biomimicry composite of the natural bone structure may be accomplished by combining a multifunctional nanoparticle with an organic scaffold.

METHODS

In this study, a quaternary ammonium silane-modified mesoporous silica containing nano silver (Ag@QHMS) was successfully synthesized and further combined with silk fibroin (SF) to fabricate the multifunctional nano-reinforced scaffold (SF-Ag@QHMS) using the freeze-drying method. Furthermore, the antibacterial and osteogenic effects of this composite were evaluated in vitro and in vivo.

RESULTS

SF-Ag@QHMS inherited a three-dimensional porous structure (porosity rate: 91.90 ± 0.62%) and better mechanical characteristics (2.11 ± 0.06 kPa) than that of the SF scaffold (porosity rate: 91.62 ± 1.65%; mechanic strength: 2.02 ± 0.01 kPa). Simultaneously, the introduction of versatile nanoparticles has provided the composite with additional antibacterial ability against Porphyromonas gingivalis, which can be maintained for 15 days. Furthermore, the expression of osteogenic-associated factors was up-regulated due to the silver ions eluting from the composite scaffold. The in vivo micro-CT and histological results indicated that the new bone formation was not only localized around the border of the defect but also arose more in the center with the support of the composite.

CONCLUSION

The multifunctional silver-loaded mesoporous silica enhanced the mechanical strength of the composite while also ensuring greater and sustained antibacterial and osteogenic properties, allowing the SF-Ag@QHMS composite to be used to repair infected bone defects.

Melanin-like nanoparticles loaded with Ag NPs for rapid photothermal sterilization and daily protection of textiles

The dual-function antibacterial and photothermal melanin-like nanoparticles (Ag NPs@Fe3+-SMNPs) were prepared and used for fabric modification. The modified fabric had excellent photothermal and antibacterial performance. By Xenon lamp irradiation, the temperature of the fabric surface rises rapidly to over 80 °C in 30 s. The modified fabric had the photothermal sterilization rates of 99% against E. coli or S. aureus after 10 min of Xenon lamp irradiation. Meanwhile, Ag NPs provided excellent antibacterial properties to the modified fabric used in daily life, and the antibacterial rate of the modified fabric was 99%. Additionally, the modified fabric showed excellent air and moisture permeability, and had excellent photothermal and antibacterial properties after 20 times of washing and 100 times of rubbing. The modified fabric was modified with the antibacterial and photothermal dual-function melanin-like nanoparticles, showing great potential in personal protective equipment (such as masks) to meet people's needs in the future.

Evaluation of the Antibacterial Properties of Iron Oxide, Polyethylene Glycol, and Gentamicin Conjugated Nanoparticles against Some Multidrug-Resistant Bacteria

Antibacterial resistance is observed as a public health issue around the world. Every day, new resistance mechanisms appear and spread over the world. For that reason, it is imperative to improve the treatment schemes that have been developed to treat infections caused by wound infections, for instance, Staphylococcus epidermidis (S. epidermidis), Proteus mirabilis (P. mirabilis), and Acinetobacter baumannii (A. baumannii). In this case, we proposed a method that involves mixing the Gentamicin (Gen) with iron oxide nanoparticles (Fe3O4 NPs) and a polymer (polyethylene glycol (PEG)) with Fe3O4 NPs. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize Fe3O4 NPs. Zeta potential and dynamic light scattering (DLS) were also assessed. The antibacterial activity of Fe3O4 NPs, Fe3O4 NPs+PEG, Fe3O4 NPs+Gen, and Fe3O4 NPs+PEG+Gen composites was investigated. The results showed a significant improvement in the antibacterial activity of nanoparticles against bacterial isolates, especially for the Fe3O4 NPs+PEG+Gen as the diameter of the inhibition zone reached 26.33 ± 0.57 mm for A. baumannii, 25.66 ± 0.57 mm for P. mirabilis, and 23.66 ± 0.57 mm for S. epidermidis. The Fe3O4 NPs, Fe3O4 NPs+PEG, Fe3O4+Gen, and Fe3O4+PEG+Gen also showed effectiveness against the biofilm produced by these isolated bacteria. The minimum inhibitory concentration (MIC) of Fe3O4 NPs for S. epidermidis was 25 µg mL−1 and for P. mirabilis and A. baumannii was 50 µg mL−1. The findings suggest that the prepared nanoparticles could be potential therapeutic options for treating wound infections caused by S. epidermidis, P. mirabilis, and A. baumannii.

Silver loaded biodegradable carboxymethyl chitin films with long-lasting antibacterial activity for infected wound healing

Bacteria-related infections are one of the main causes of human skin infections, which are associated with the delay of wound healing and secondary complications. In this work, a series of novel biodegradable films based on thermosensitive carboxymethyl chitin were prepared without using any crosslinkers. All the carboxymethyl chitin films had good flexibility, high transparency, and appropriate water absorption capacity, and could provide a moist environment for wound healing. The silver ions (Ag⁺) were incorporated on the LTCF-5 film, which had the best mechanical strength (56.39 MPa in the dry state and 0.66 MPa in the wet state) among the carboxymethyl chitin films and was higher than those of the reported biodegradable dressings and commercially available dressings. Compared with the commercial hydrofiber dressing with silver (AQUACEL®), the composite film could provide slow and sustained release of Ag⁺ with good strength and biodegradability, and displayed excellent long-lasting antibacterial activity in vitro against both S. aureus and E. coli without obvious cytotoxicity, which still possessed good antibacterial activity with almost 100% bacteriostatic rates after soaking in phosphate buffered saline for 7 days. More importantly, the Ag⁺ loaded carboxymethyl chitin film could promote infected cutaneous wound healing in a S. aureus infected full-thickness cutaneous defect in vivo model because of its long-lasting antibacterial activity, good biocompatibility, exudate absorption and ability to maintain a moist environment. Thus Ag⁺ loaded carboxymethyl chitin films are excellent candidates for infected wound healing.

Hybrid Ag nanoparticles/polyoxometalate-polydopamine nano-flowers loaded chitosan/gelatin hydrogel scaffolds with synergistic photothermal/chemodynamic/Ag+ anti-bacterial action for accelerated wound healing

Bacterial infections significantly slow the wound healing process, thus severely threatening human health. Furthermore, traditional antibiotics may promote the development of multidrug-resistant bacteria. Therefore, developing novel bactericides and therapeutic strategies for bacterial infections is important to enhance wound healing. Herein, a three-in-one bactericidal flower-like nanocomposite was assembled using Ag nanoparticles/phosphotungstic acid-polydopamine nano-flowers (AgNPs/POM-PDA). The nanocomposite exhibited photothermal therapy (PTT) when exposed to NIR light via photothermal conversion by PDA. The resultant photothermal effect accelerated and controlled the Ag⁺ released from AgNPs. The chemodynamic therapy (CDT) was obtained via POM catalytic Fenton-like reaction. The combined PTT/CDT/Ag⁺ treatment achieved excellent synergistic anti-bacterial activity against both gram-negative E. coli and gram-positive S. aureus. A multifunctional wound dressing was then obtained by embedding the AgNPs/POM-PDA flower-like nanocomposite into the chitosan (CS)/gelatin (GE) biocomposite hydrogel. The synergy of AgNPs/POM-PDA nanocomposites and CS/GE hydrogel remarkably accelerated wound healing in vivo due to the excellent biocompatibility, hydroabsorptivity, and breathability of the hydrogel. In this study, a multifunctional agent was developed to synergistically combat bacterial infections and accelerate wound healing.

Multifunctional chitosan/gelatin@tannic acid cryogels decorated with in situ reduced silver nanoparticles for wound healing

Background

Most traditional wound dressings only partially meet the needs of wound healing because of their single function. Patients usually suffer from the increasing cost of treatment and pain resulting from the frequent changing of wound dressings. Herein, we have developed a mutifunctional cryogel to promote bacterial infected wound healing based on a biocompatible polysaccharide.

Methods

The multifunctional cryogel is made up of a compositive scaffold of chitosan (CS), gelatin (Gel) and tannic acid (TA) and in situ formed silver nanoparticles (Ag NPs). A liver bleeding rat model was used to evaluate the dynamic hemostasis performance of the various cryogels. In order to evaluate the antibacterial properties of the prepared cryogels, gram-positive bacterium Staphylococcus aureus (S. aureus) and gram-negative bacterium Escherichia coli (E. coli) were cultured with the cryogels for 12 h. Meanwhile, S. aureus was introduced to cause bacterial infection in vivo. After treatment for 2 days, the exudates from wound sites were dipped for bacterial colony culture. Subsequently, the anti-inflammatory effect of the various cryogels was evaluated by western blotting and enzyme-linked immunosorbent assay. Finally, full-thickness skin defect models on the back of SD rats were established to assess the wound healing performances of the cryogels.

Results

Due to its porous structure, the multifunctional cryogel showed fast liver hemostasis. The introduced Ag NPs endowed the cryogel with an antibacterial efficiency of >99.9% against both S. aureus and E. coli. Benefited from the polyphenol groups of TA, the cryogel could inhibit nuclear factor-κB nuclear translocation and down-regulate inflammatory cytokines for an anti-inflammatory effect. Meanwhile, excessive reactive oxygen species could also be scavenged effectively. Despite the presence of Ag NPs, the cryogel did not show cytotoxicity and hemolysis. Moreover, in vivo experiments demonstrated that the biocompatible cryogel displayed effective bacterial disinfection and accelerated wound healing.

Conclusions

The multifunctional cryogel, with fast hemostasis, antibacterial and anti-inflammation properties and the ability to promote cell proliferation could be widely applied as a wound dressing for bacterial infected wound healing.

Polyhexamethylene guanidine hydrochloride modified sodium alginate nonwoven with potent antibacterial and hemostatic properties for infected full-thickness wound healing

The development of multifunctional wound dressings has always been considered as a promising strategy to promote blood coagulation, inhibit bacterial infection, and accelerate wound healing. Herein, an antibacterial and hemostatic dressing (SA-PHMG) was developed based on sodium alginate (SA) nonwoven and polyhexamethylene guanidine hydrochloride (PHMG) through a completely green industrial route, including dipping, padding, and drying. According to studies, SA-PHMG dressings exhibited excellent liquid absorption capacity and water vapor permeability. Moreover, bactericidal assays have demonstrated that SA-PHMG dressings have ideal antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and mixed bacteria, maintaining potent antibacterial activity even after 10 cycles of antibacterial trials or 50 times of washing or soaping. The in vitro evaluation of the hemostatic effect indicated that the SA-PHMG could significantly promote blood clotting by activating platelets, and in vitro and in vivo hemolysis, cytotoxicity and skin irritation studies demonstrated the ideal biocompatibility of the dressings. In addition, better wound closure and tissue regeneration were recorded using SA-PHMG nonwoven as the dressing based on an infected full-thickness wound model. In conclusion, this antibacterial, hemostatic, biocompatible, and environmentally friendly SA-PHMG nonwoven exhibit the potential for infected wound healing.

Nanoparticle-Containing Wound Dressing: Antimicrobial and Healing Effects

The dressings containing nanoparticles of metals and metal oxides are promising types of materials for wound repair. In such dressings, biocompatible and nontoxic hydrophilic polymers are used as a matrix. In the present review, we take a look at the anti-microbial effect of the nanoparticle-modified wound dressings against various microorganisms and evaluate their healing action. A detailed analysis of 31 sources published in 2021 and 2022 was performed. Furthermore, a trend for development of modern antibacterial wound-healing nanomaterials was shown as exemplified in publications starting from 2018. The review may be helpful for researchers working in the areas of biotechnology, medicine, epidemiology, material science and other fields aimed at the improvement of the quality of life.

Solvent Casting and UV Photocuring for Easy and Safe Fabrication of Nanocomposite Film Dressings

The aim of this work was to optimize and characterize nanocomposite films based on gellan gum methacrylate (GG-MA) and silver nanoparticles (AgNPs) for application in the field of wound dressing. The films were produced using the solvent casting technique coupled with a photocuring process. The UV irradiation of GG-MA solutions containing glycerol as a plasticizer and different amounts of silver nitrate resulted in the concurrent crosslinking of the photocurable polymer and a reduction of Ag ions with consequent in situ generation of AgNPs. In the first part of the work, the composition of the films was optimized, varying the concentration of the different components, the GG-MA/glycerol and GG-MA/silver nitrate weight ratios as well as the volume of the film-forming mixture. Rheological analyses were performed on the starting solutions, whereas the obtained films were characterized for their mechanical properties. Colorimetric analyses and swelling studies were also performed in order to determine the AgNPs release and the water uptake capacity of the films. Finally, microbiological tests were carried out to evaluate the antimicrobial efficacy of the optimized films, in order to demonstrate their possible application as dressings for the treatment of infected hard-to-heal wounds, which is a demanding task for public healthcare.