Synthesis and antimicrobial activity of monodisperse copper nanoparticles

Use of nanotechnology-based nanomaterial as a substitute for antibiotics in monogastric animals

Nanotechnology has emerged as a promising solution for tackling antibiotic resistance in monogastric animals, providing innovative methods to enhance animal health and well-being. This review explores the novel use of nanotechnology-based nanomaterials as substitutes for antibiotics in monogastric animals. With growing global concerns about antibiotic resistance and the need for sustainable practices in animal husbandry, nanotechnology offers a compelling avenue to address these challenges. The objectives of this review are to find out the potential of nanomaterials in improving animal health while reducing reliance on conventional antibiotics. We examine various forms of nanomaterials and their roles in promoting gut health and also emphasize fresh perspectives brought by integrating nanotechnology into animal healthcare. Additionally, we delve into the mechanisms underlying the antibacterial properties of nanomaterials and their effectiveness in combating microbial resistance. By shedding light on the transformative role of nanotechnology in animal production systems. This review contributes to our understanding of how nanotechnology can provide safer and more sustainable alternatives to antibiotics.

Promising biomedical systems based on copper nanoparticles: Synthesis, characterization, and applications

Copper and copper oxide nanoparticles (CuNPs) have unique physicochemical properties that make them highly promising for biomedical applications. This review discusses the application of CuNPs in biomedicine, including diagnosis, therapy, and theranostics. Recent synthesis methods, with an emphasis on green approaches, are described, and the latest techniques for nanoparticle characterization are critically analyzed. CuNPs, including Cu2O, CuO, and Cu, have significant potential as anti-cancer agents, drug delivery systems, and photodynamic therapy enhancers, among other applications. While challenges such as ensuring biocompatibility and stability must be addressed, the state-of-the-art research reviewed here provides strong evidence for the efficacy and versatility of CuNPs. These multifunctional properties have been extensively researched and documented, showcasing the immense potential of CuNPs in biomedicine. Overall, the evidence suggests that CuNPs are a promising avenue for future research and development in biomedicine. We strongly support further progress in the development of synthesis and application strategies to enhance the effectiveness and safety of CuNPs for clinical purposes.

A sustainable approach to prepare green synthesis of copper nanoparticles of Bauhinia variegata & Saussurea lappa: Unveiling in-vitro anti-obesity applications

Nanoparticles have different shapes and sizes between the range of 1-100 nm, which show advantages for stabilizing compounds, higher carrier capacity, and lower costs. Metal nanoparticles such as copper, gold, silver, and zinc are favorable components for various applications due to their interesting properties. In the present study, nanoparticles were synthesized by reduction with flower extracts of Bauhinia variegate & Saussurea lappa that were used to stabilize the copper nanoparticles. Furthermore, the characterization of plants synthesized copper nanoparticles was carried out through UV-visible dynamic light scattering. Additionally, morphological characterization of nanoparticles was confirmed by scanning electron microscopy and energy dispersive X-ray spectroscopy confirmed the elemental composition of copper nanoparticles. Powder X-ray diffraction was conducted for the analysis of crystallinity, purity, and crystal size of plant-synthesized copper nanoparticles. The average particle size was evaluated and exhibited the particle size at the peak of 8.721 nm and 98.03 nm for flower extracts of Bauhinia variegate & Saussurea lappa copper nanoparticles. The Fourier Transform Infrared spectrum was taken to scrutinize the various functional groups that were responsible for the reduction of the copper ions. The antimicrobial results against the bacterial strains with the positive test results of the zone of inhibition were for Bauhinia variegate (17 mm, 18 mm, 19 mm, and 18 mm) and Saussurea lappa (17 mm, 19 mm, 18 mm, and 18 mm) respectively for plants synthesized copper nanoparticles against the Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Pseudomonas aeruginosa. Lipase inhibition assay and Amylase inhibition assay with different concentrations (20 μg/mL to 100 μg/mL) for Bauhinia variegate & Saussurea lappa (12.34 %-59.67 % and 10.50 %-47.01 %) and (34.52 %-89.02 % and 22.34 %-56.45 %) confirmed the anti-obesity and anti-diabetic activities of plants extract synthesized copper nanoparticles.

Nanoparticles incorporated hydrogels for delivery of antimicrobial agents: developments and trends

The prevention and treatment of microbial infections is an imminent global public health concern due to the poor antimicrobial performance of the existing antimicrobial regime and rapidly emerging antibiotic resistance in pathogenic microbes. In order to overcome these problems and effectively control bacterial infections, various new treatment modalities have been identified. To attempt this, various micro- and macro-molecular antimicrobial agents that function by microbial membrane disruption have been developed with improved antimicrobial activity and lesser resistance. Antimicrobial nanoparticle-hydrogels systems comprising antimicrobial agents (antibiotics, biological extracts, and antimicrobial peptides) loaded nanoparticles or antimicrobial nanoparticles (metal or metal oxide) constitute an important class of biomaterials for the prevention and treatment of infections. Hydrogels that incorporate nanoparticles can offer an effective strategy for delivering antimicrobial agents (or nanoparticles) in a controlled, sustained, and targeted manner. In this review, we have described an overview of recent advancements in nanoparticle-hydrogel hybrid systems for antimicrobial agent delivery. Firstly, we have provided an overview of the nanoparticle hydrogel system and discussed various advantages of these systems in biomedical and pharmaceutical applications. Thereafter, different hybrid hydrogel systems encapsulating antibacterial metal/metal oxide nanoparticles, polymeric nanoparticles, antibiotics, biological extracts, and antimicrobial peptides for controlling infections have been reviewed in detail. Finally, the challenges and future prospects of nanoparticle-hydrogel systems have been discussed.

Biosynthesis of copper nanoparticles using Alstonia scholaris leaves and its antimicrobial studies

The utilization of plants for the production of metallic nanoparticles is gaining significant attention in research. In this study, we conducted phytochemical screening of Alstonia scholaris (A. scholaris) leaves extracts using various solvents, including chloroform, ethyl acetate, n-hexane, methanol, and water. Our findings revealed higher proportions of flavonoids and alkaloids in both solvents compared to other phytochemical species. In the methanol, extract proteins, anthraquinone and reducing sugar were not detected. On the other hand, the aqueous extract demonstrated the presence of amino acids, reducing sugar, phenolic compounds, anthraquinone, and saponins. Notably, ethyl acetate and chloroform extracts displayed the highest levels of bioactive compounds among all solvents. Intrigued by these results, we proceeded to investigate the antibacterial properties of the leaf extracts against two major bacterial strains, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). All extracts exhibited significant zones of inhibition against both bacterial isolates, with S. aureus showing higher susceptibility compared to E. coli. Notably, the methanol extract displayed the most potent I hibitory effect against all organisms. Inspired by the bioactivity of the methanol extract, we employed it as a plant-based material for the green synthesis of copper nanoparticles (Cu-NPs). The synthesized Cu-NPs were characterized using Fourier infrared spectroscopy (FT-IR), UV-visible spectroscopic analysis, and scanning electron microscopy (SEM). The observed color changes confirmed the successful formation of Cu-NPs, while the FTIR analysis matched previously reported peaks, further verifying the synthesis. The SEM micrographs indicated the irregular shapes of the surface particles. From the result obtained by energy dispersive X-ray spectroscopic analysis, Cu has the highest relative abundance of 67.41 wt%. Confirming the purity of the Cu-NPs colloid. These findings contribute to the growing field of eco-friendly nanotechnology and emphasize the significance of plant-mediated approaches in nanomaterial synthesis and biomedical applications.

Gold nanoparticle adsorption alters the cell stiffness and cell wall bio-chemical landscape of Candida albicans fungal cells

HYPOTHESIS

Nanomaterials have been extensively investigated for a wide range of biomedical applications, including as antimicrobial agents, drug delivery vehicles, and diagnostic devices. The commonality between these biomedical applications is the necessity for the nanoparticle to interact with or pass through the cellular wall and membrane. Cell-nanomaterial interactions/uptake can occur in various ways, including adhering to the cell wall, forming aggregates on the surface, becoming absorbed within the cell wall itself, or transversing into the cell cytoplasm. These interactions are common to mammalian cells, bacteria, and yeast cells. This variety of interactions can cause changes to the integrity of the cell wall and the cell overall, but the precise mechanisms underpinning such interactions remain poorly understood. Here, we investigate the interaction between commonly investigated gold nanoparticles (AuNPs) and the cell wall/membrane of a model fungal cell to explore the general effects of interaction and uptake.

EXPERIMENTS

The interactions between 100 nm citrate-capped AuNPs and the cell wall of Candida albicans fungal cells were studied using a range of advanced microscopy techniques, including atomic force microscopy, confocal laser scanning microscopy, scanning electron microscopy, transmission electron microscopy, and synchrotron-FTIR micro-spectroscopy.

FINDINGS

In most cases, particles adhered on the cell surface, although instances of particles being up-taken into the cell cytoplasm and localised within the cell wall and membrane were also observed. There was a measurable increase in the stiffness of the fungal cell after AuNPs were introduced. Analysis of the synchrotron-FTIR data showed significant changes in spectral features associated with phospholipids and proteins after exposure to AuNPs.

The Addition of Co into CuO-ZnO Oxides Triggers High Antibacterial Activity and Low Cytotoxicity

In the present work, a simple two-step method is proposed for mixed oxide synthesis aimed at the achievement of antibacterial nanomaterials. In particular, Cu, Zn and Co have been selected to achieve single-, double- and triple-cation oxides. The synthesized samples are characterized by XRD, IR, SEM and EDX, indicating the formation of either crystalline or amorphous hydrocarbonate precursors. The oxides present one or two crystalline phases, depending on their composition; the triple-cation oxides form a solid solution of tenorite. Also, the morphology of the samples varies with the composition, yielding nanoparticles, filaments and hydrangea-like microaggregates. The antibacterial assays are conducted against E. coli and indicate an enhanced efficacy, especially displayed by the oxide containing 3% Co and 9% Zn incorporated into the CuO lattice. The oxides with the highest antibacterial properties are tested for their cytotoxicity, indicating a low toxicity impact, in line with literature data.

Structural Analysis of Cu+ and Cu2+ Ions in Zeolite as a Nanoreactor with Antibacterial Applications

In this work, we report the structural analysis of Cu+ and Cu2+ ions in zeolite as a nanoreactor with antibacterial applications. A simple one-step process was implemented to obtain Cu ions in zeolite A (ZA4) by controlling the temperature in the solutions to guarantee the ions' stability. Samples were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy, showing the characteristic zeolite elements as well as the characteristic bands with slight modifications in the chemical environment of the zeolite nanoreactor attributed to Cu ions by FT-IR spectroscopy. In addition, a shift of the characteristic peaks of ZA4 in X-ray diffraction was observed as well as a decrease in relative peak intensity. On the other hand, the antibacterial activity of Cu ions in the zeolite nanoreactor was evaluated.

Management of potato brown rot disease using chemically synthesized CuO-NPs and MgO-NPs

BACKGROUND

Potatoes are a crucial vegetable crop in Egypt in terms of production and consumption. However, the potato industry suffers significant annual losses due to brown rot disease. This study aimed to suppress Ralstonia solanacearum (R. solanacearum), the causative agent of brown rot disease in potatoes, using efficient and economical medications such as CuO and MgO metal oxide nanoparticles, both in vitro and in vivo, to reduce the risk of pesticide residues.

RESULTS

CuO and MgO metal oxide nanoparticles were synthesized via a simple chemical process. The average particle size, morphology, and structure of the nanoparticles were characterized using UV-visible spectroscopy, transmission electron microscopy (TEM), zeta potential analysis, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The growth of R. solanacearum was strongly inhibited by CuO and MgO NPs at a concentration of 3 mg/mL, resulting in zones of inhibition (ZOI) of 19.3 mm and 17 mm, respectively. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CuO-NPs and MgO-NPs were 0.5, 0.6, and 0.6, 0.75 mg/mL, respectively. When applied in vivo through seed dressing and tuber soaking at their respective MIC concentrations, CuO-NPs and MgO-NPs significantly reduced the incidence of brown rot disease to 71.2% and 69.4%, respectively, compared to 43.0% and 39.5% in bulk CuSO₄ and bulk MgSO₄ treatments, respectively. Furthermore, CuO-NPs and MgO-NPs significantly increased the yield, total chlorophyll content, and enzyme efficiency of potato plants compared with the infected control plants. TEM revealed that the bacterial cytomembrane was severely damaged by nanomechanical forces after interaction with CuO-NPs and MgO-NPs, as evidenced by lipid peroxidation and ultrastructural investigations.

CONCLUSION

The results of this study suggest that CuO-NPs and MgO-NPs can be used as intelligent agents to manage plant pathogens in agriculture. The use of metal oxide nanoparticles could provide a risk-free alternative for treating plant diseases, which are currently one of the biggest challenges faced by the potato industry in Egypt. The significant increase in yield, photosynthetic pigments, enzymatic activity, and total phenol-promoted resistance to R. solanacearum in potato plants treated with CuO-NPs and MgO-NPs compared to infected control plants highlights the potential benefits for the potato industry in Egypt. Further investigations are needed to explore using metal oxide nanoparticles for treating other plant diseases.

Wound healing strategies based on nanoparticles incorporated in hydrogel wound patches

The intricate, tightly controlled mechanism of wound healing that is a vital physiological mechanism is essential to maintaining the skin's natural barrier function. Numerous studies have focused on wound healing as it is a massive burden on the healthcare system. Wound repair is a complicated process with various cell types and microenvironment conditions. In wound healing studies, novel therapeutic approaches have been proposed to deliver an effective treatment. Nanoparticle-based materials are preferred due to their antibacterial activity, biocompatibility, and increased mechanical strength in wound healing. They can be divided into six main groups: metal NPs, ceramic NPs, polymer NPs, self-assembled NPs, composite NPs, and nanoparticle-loaded hydrogels. Each group shows several advantages and disadvantages, and which material will be used depends on the type, depth, and area of the wound. Better wound care/healing techniques are now possible, thanks to the development of wound healing strategies based on these materials, which mimic the extracellular matrix (ECM) microenvironment of the wound. Bearing this in mind, here we reviewed current studies on which NPs have been used in wound healing and how this strategy has become a key biotechnological procedure to treat skin infections and wounds.

Essential oil-grafted copper nanoparticles as a potential next-generation fungicide for holistic disease management in maize

Sustainable food production is necessary to meet the demand of the incessantly growing human population. Phytopathogens pose a major constraint in food production, and the use of conventional fungicides to manage them is under the purview of criticism due to their numerous setbacks. In the present study, essential oil-grafted copper nanoparticles (EGC) were generated, characterized, and evaluated against the maize fungal pathogens, viz., Bipolaris maydis, Rhizoctonia solani f. sp. sasakii, Macrophomina phaseolina, Fusarium verticillioides, and Sclerotium rolfsii. The ED₅₀ for the fungi under study ranged from 43 to 56 μg ml^-1, and a significant inhibition was observed at a low dose of 20 μg ml^-1 under in vitro conditions. Under net house conditions, seed treatment + foliar spray at 250 and 500 mg L^-1 of EGC performed remarkably against maydis leaf blight (MLB), with reduced percent disease index (PDI) by 27.116 and 25.292%, respectively, in two Kharif seasons (May-Sep, 2021, 2022). The activity of enzymatic antioxidants, viz., β-1, 3-glucanase, PAL, POX, and PPO, and a non-enzymatic antioxidant (total phenolics) was increased in treated maize plants, indicating host defense was triggered. The optimum concentrations of EGC (250 mg L^-1 and 500 mg L^-1) exhibited improved physiological characteristics such as photosynthetic activity, shoot biomass, plant height, germination percentage, vigor index, and root system traits. However, higher concentrations of 1,000 mg L^-1 rendered phytotoxicity, reducing growth, biomass, and copper bioaccumulation to high toxic levels, mainly in the foliar-sprayed maize leaves. In addition, EGC and copper nanoparticles (CuNPs) at 1,000 mg L^-1 reduced the absorption and concentration of manganese and zinc indicating a negative correlation between Cu and Mn/Zn. Our study proposes that the CuNPs combined with EO (Clove oil) exhibit astounding synergistic efficacy against maize fungal pathogens and optimized concentrations can be used as an alternative to commercial fungicides without any serious impact on environmental health.

Hybrid materials based on chitosan functionalized with green synthesized copper nanoparticles: Physico-chemical and antimicrobial analysis

Recently, the development of materials with antimicrobial properties has become a challenge under scrutiny. The incorporation of copper nanoparticles (NpCu) into a chitosan matrix appears to represent a viable strategy to contain the particles and prevent their oxidation. Regarding the physical properties, the nanocomposite films (CHCu) showed a decrease in the elongation at break (5 %) and an increase in the tensile strength of 10 % concerning chitosan films (control). They also showed solubility values lower than 5 % while the swelling diminished by 50 %, on average. The dynamical mechanical analysis (DMA) of nanocomposites revealed two thermal events located at 113° and 178 °C, which matched the glass transitions of the CH-enriched phase and nanoparticles-enriched phase, respectively. In addition, the thermogravimetric analysis (TGA) detected a greater stability of the nanocomposites. Chitosan films and the NpCu-loaded nanocomposites demonstrated excellent antibacterial capacity against Gram-negative and Gram-positive bacteria, proved through diffusion disc, zeta potential, and ATR-FTIR techniques. Additionally, the penetration of individual NpCu particles into bacterial cells and the leakage of cell content were verified by TEM. The mechanism of the antibacterial activity of the nanocomposites involved the interaction of chitosan with the bacterial outer membrane or cell wall and the diffusion of the NpCu through the cells. These materials could be applied in diverse fields of biology, medicine, or food packaging.

Review of Antimicrobial Nanocoatings in Medicine and Dentistry: Mechanisms of Action, Biocompatibility Performance, Safety, and Benefits Compared to Antibiotics

This review discusses topics relevant to the development of antimicrobial nanocoatings and nanoscale surface modifications for medical and dental applications. Nanomaterials have unique properties compared to their micro- and macro-scale counterparts and can be used to reduce or inhibit bacterial growth, surface colonization and biofilm development. Generally, nanocoatings exert their antimicrobial effects through biochemical reactions, production of reactive oxygen species or ionic release, while modified nanotopographies create a physically hostile surface for bacteria, killing cells via biomechanical damage. Nanocoatings may consist of metal nanoparticles including silver, copper, gold, zinc, titanium, and aluminum, while nonmetallic compounds used in nanocoatings may be carbon-based in the form of graphene or carbon nanotubes, or composed of silica or chitosan. Surface nanotopography can be modified by the inclusion of nanoprotrusions or black silicon. Two or more nanomaterials can be combined to form nanocomposites with distinct chemical or physical characteristics, allowing combination of different properties such as antimicrobial activity, biocompatibility, strength, and durability. Despite their wide range of applications in medical engineering, questions have been raised regarding potential toxicity and hazards. Current legal frameworks do not effectively regulate antimicrobial nanocoatings in matters of safety, with open questions remaining about risk analysis and occupational exposure limits not considering coating-based approaches. Bacterial resistance to nanomaterials is also a concern, especially where it may affect wider antimicrobial resistance. Nanocoatings have excellent potential for future use, but safe development of antimicrobials requires careful consideration of the "One Health" agenda, appropriate legislation, and risk assessment.

Chitosan-Decorated Copper Oxide Nanocomposite: Investigation of Its Antifungal Activity against Tomato Gray Mold Caused by Botrytis cinerea

Owing to the remarkable antimicrobial potential of these materials, research into the possible use of nanomaterials as alternatives to fungicides in sustainable agriculture is increasingly progressing. Here, we investigated the potential antifungal properties of chitosan-decorated copper oxide nanocomposite (CH@CuO NPs) to control gray mold diseases of tomato caused by Botrytis cinerea throughout in vitro and in vivo trials. The nanocomposite CH@CuO NPs were chemically prepared, and size and shape were determined using Transmission Electron Microscope (TEM). The chemical functional groups responsible for the interaction of the CH NPs with the CuO NPs were detected using the Fourier Transform Infrared (FTIR) spectrophotometry. The TEM images confirmed that CH NPs have a thin and semitransparent network shape, while CuO NPs were spherically shaped. Furthermore, the nanocomposite CH@CuO NPs ex-habited an irregular shape. The size of CH NPs, CuO NPs and CH@CuO NPs as measured through TEM, were approximately 18.28 ± 2.4 nm, 19.34 ± 2.1 nm, and 32.74 ± 2.3 nm, respectively. The antifungal activity of CH@CuO NPs was tested at three concentrations of 50, 100 and 250 mg/L and the fungicide Teldor 50% SC was applied at recommended dose 1.5 mL/L. In vitro experiments revealed that CH@CuO NPs at different concentrations significantly inhibited the reproductive growth process of B. cinerea by suppressing the development of hyphae, spore germination and formation of sclerotia. Interestingly, a significant control efficacy of CH@CuO NPs against tomato gray mold was observed particularly at concentrations 100 and 250 mg/L on both detached leaves (100%) as well as the whole tomato plants (100%) when compared to the conventional chemical fungicide Teldor 50% SC (97%). In addition, the tested concentration 100 mg/L improved to be sufficient to guarantee a complete reduction in the disease's severity (100%) to tomato fruits from gray mold without any morphological toxicity. In comparison, tomato plants treated with the recommended dose 1.5 mL/L of Teldor 50% SC ensured disease reduction up to 80%. Conclusively, this research enhances the concept of agro-nanotechnology by presenting how a nano materials-based fungicide could be used to protect tomato plants from gray mold under greenhouse conditions and during the postharvest stage.

Silver and Copper Nanoparticles as the New Biocidal Agents Used in Pre- and Post-Milking Disinfectants with the Addition of Cosmetic Substrates in Dairy Cows

Mastitis is one of the most common issues for milk producers around the world. Antibiotic therapy is often ineffective, and therefore, scientists must find a new solution. The aim of this paper is to estimate the influence of common and well-known cosmetic substrates and mixtures of nanoparticles (NPs) and cosmetic substrates on the viability of frequently occurring mastitis pathogens, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The obtained results suggest that only collagen + elastin and glycerine influenced and increased bacteria viability. In case of the rest of the cosmetic substrates, the viability of E. coli and S. aureus was decreased, and the results were statistically significant (p ≤ 0.01). Prepared pre-dipping and dipping mixtures decrease (p ≤ 0.01) the viability of the mentioned pathogens. The obtained results of the in vitro analysis are very promising. In the next step, prepared mixtures should be tested in different herd conditions if they can be used in mastitis prevention or decrease the number of subclinical mastitis cases. Furthermore, these mixtures could become an interesting alternative for organic milk production where conventional preparations and antibiotics are forbidden. However, further analysis, especially on the influence of prepared mixtures on other bacteria species and, algae, fungi, are necessary.

Copper-coated hospital surfaces: reduction of total bacterial loads and resistant Acinetobacter spp

Healthcare-associated infections (HAIs) represent a global challenge and an even more staggering concern when related to microorganisms capable of resisting and surviving for long periods in the environment, such as Acinetobacter spp. Strategies that allow a reduction of pathogens from hospital environments represent an additional barrier in infection control protocols, minimizing transmission to hospitalized patients. Considering the antimicrobial properties of copper, here, the bacterial load and the presence of Acinetobacter spp. were monitored on high handling surfaces covered by 99.9% copper films on intensive and non-intensive care unit bedrooms in a tertiary care hospital. Firstly, copper-coated films were able to inhibit the adhesion and biofilm formation of A. baumannii strains in in vitro assays. On the other hand, Acinetobacter spp. were isolated from both copper-coated and uncoated surfaces in the hospital, although the majority was detected on surfaces without copper. All carbapenem-resistant A. baumannii isolates identified harbored the blaoxa-23 gene, while the A. nosocomialis isolates were susceptible to most antimicrobials tested. All isolates were susceptible to polymyxin B. Regarding the total aerobic bacteria, surfaces with copper-coated films presented lower total loads than those detected for controls. Copper coating films may be a workable strategy to mitigate HAIs, given their potential in reducing bacterial loads in nosocomial environments, including threatening pathogens like A. baumannii.

Highly Antifungal Activity of Biosynthesized Copper Oxide Nanoparticles against Candida albicans

Candida albicans (ATCC SC5314) was exposed to biosynthesized copper oxide nanoparticles (CuONPs) to determine their inhibitory capacity. Nanoparticles were polydisperse of small size (5.8 ± 3.5 nm) with irregular shape. The minimum inhibitory concentration (MIC) against C. albicans was 35.5 µg/mL. The production of reactive oxygen species (ROS) of C. albicans was verified when exposed to different concentrations of CuONPs. Ultrastructural analysis of C. albicans revealed a high concentration of CuONPs in the cytoplasm and outside the cell; also, nanoparticles were detected within the cell wall. Cytotoxic analyses using fibroblasts (L929), macrophages (RAW 264.7), and breast (MCF-12) cell lines show good results of cell viability when exposed at the MIC. Additionally, a hemocompatibility analysis was carried out and was found to be below 5%, considered the threshold for biocompatibility. Therefore, it is concluded that the biosynthesized CuONPs have a high potential for developing a topical antifungal treatment.

Breaking down the cell wall: Still an attractive antibacterial strategy

Since the advent of penicillin, humans have known about and explored the phenomenon of bacterial inhibition via antibiotics. However, with changes in the global environment and the abuse of antibiotics, resistance mechanisms have been selected in bacteria, presenting huge threats and challenges to the global medical and health system. Thus, the study and development of new antimicrobials is of unprecedented urgency and difficulty. Bacteria surround themselves with a cell wall to maintain cell rigidity and protect against environmental insults. Humans have taken advantage of antibiotics to target the bacterial cell wall, yielding some of the most widely used antibiotics to date. The cell wall is essential for bacterial growth and virulence but is absent from humans, remaining a high-priority target for antibiotic screening throughout the antibiotic era. Here, we review the extensively studied targets, i.e., MurA, MurB, MurC, MurD, MurE, MurF, Alr, Ddl, MurI, MurG, lipid A, and BamA in the cell wall, starting from the very beginning to the latest developments to elucidate antimicrobial screening. Furthermore, recent advances, including MraY and MsbA in peptidoglycan and lipopolysaccharide, and tagO, LtaS, LspA, Lgt, Lnt, Tol-Pal, MntC, and OspA in teichoic acid and lipoprotein, have also been profoundly discussed. The review further highlights that the application of new methods such as macromolecular labeling, compound libraries construction, and structure-based drug design will inspire researchers to screen ideal antibiotics.

Antimicrobial Effects of Nanostructured Rare-Earth-Based Orthovanadates

The search for novel antimicrobial agents is of huge importance. Nanomaterials can come to the rescue in this case. The aim of this study was to assess the cytotoxicity and antimicrobial effects of rare-earth-based orthovanadate nanoparticles. The cytotoxicity against host cells and antimicrobial activity of LaVO₄:Eu³⁺ and GdVO₄:Eu³⁺ nanoparticles were analyzed. Effects of nanomaterials on fibroblasts were assessed by MTT, neutral red uptake and scratch assays. The antimicrobial effects were evaluated by the micro-dilution method estimating the minimum inhibitory concentration (MIC) of nanoparticles against various strains of microorganisms, DNA cleavage and biofilm inhibition. GdVO₄:Eu³⁺ nanoparticles were found to be less toxic against eukaryotic cells compared with LaVO₄:Eu³⁺. Both nanoparticles exhibited antimicrobial activity and the highest MIC values were 64 mg/L for E. hirae, E. faecalis and S. aureus shown by GdVO₄:Eu³⁺ nanoparticles. Nanoparticles demonstrated good DNA cleavage activity and induction of double-strand breaks in supercoiled plasmid DNA even at the lowest concentrations used. Both nanoparticles showed the biofilm inhibition activity against S. aureus at 500 mg/L and reduced the microbial cell viability. Taken the results of host toxicity and antimicrobial activity studies, it can be assumed that GdVO₄:Eu³⁺ nanoparticles are more promising antibacterial agents compared with LaVO₄:Eu³⁺ nanoparticles.

Nanostructured Antibiotics and Their Emerging Medicinal Applications: An Overview of Nanoantibiotics

Bacterial strains resistant to antimicrobial treatments, such as antibiotics, have emerged as serious clinical problems, necessitating the development of novel bactericidal materials. Nanostructures with particle sizes ranging from 1 to 100 nanometers have appeared recently as novel antibacterial agents, which are also known as “nanoantibiotics”. Nanomaterials have been shown to exert greater antibacterial effects on Gram-positive and Gram-negative bacteria across several studies. Antibacterial nanofilms for medical implants and restorative matters to prevent bacterial harm and antibacterial vaccinations to control bacterial infections are examples of nanoparticle applications in the biomedical sectors. The development of unique nanostructures, such as nanocrystals and nanostructured materials, is an exciting step in alternative efforts to manage microorganisms because these materials provide disrupted antibacterial effects, including better biocompatibility, as opposed to minor molecular antimicrobial systems, which have short-term functions and are poisonous. Although the mechanism of action of nanoparticles (NPs) is unknown, scientific suggestions include the oxidative-reductive phenomenon, reactive ionic metals, and reactive oxygen species (ROS). Many synchronized gene transformations in the same bacterial cell are essential for antibacterial resistance to emerge; thus, bacterial cells find it difficult to build resistance to nanoparticles. Therefore, nanomaterials are considered as advanced solution tools for the fields of medical science and allied health science. The current review emphasizes the importance of nanoparticles and various nanosized materials as antimicrobial agents based on their size, nature, etc.

Diospyros malabarica Fruit Extract Derived Silver Nanoparticles: A Biocompatible Antibacterial Agent

Biogenic silver nanoparticles demonstrate excellent antibacterial activity against a broad range of bacteria. Herein, aqueous biogenic silver nanoparticles (Aq@bAgNPs) and ethanolic biogenic silver nanoparticles (Et@bAgNPs) were synthesized using aqueous as well as ethanolic extracts of Diospyros malabarica fruit, respectively. The as-prepared biogenic silver nanoparticles (bAgNPs) were characterized using UV-Vis, FTIR as well as energy dispersive X-ray (EDS) spectroscopy, electron microscopy, dynamic light scattering spectroscopy (DLS), and zetasizer. The zeta potentials of Aq@bAgNPs and Et@bAgNPs were −9.8 ± 2.6, and −12.2 ± 1.9 mV, respectively. The antibacterial activity of bAgNPs was investigated against seven bacterial strains (i.e., pathogenic and nonpathogenic) and Et@bAgNPs exhibited the highest antibacterial propensity (i.e., 20 nm in diameter) against Bacillus subtillis through disk diffusion assay. The trypan blue dye exclusion assay also confirmed the antibacterial propensity of as-prepared bAgNPs. Furthermore, both Aq@bAgNPs and Et@bAgNPs oxidize bacterial membrane fatty acids and generate lipid peroxides which eventually form complexes with thiobarbituric acid (i.e., malondialdehyde-thiobarbituric acid adduct) to bring about bacterial death. Both the nanoparticles demonstrated good hemocompatibility against human as well as rat red blood cells (RBCs). In addition, they exhibited excellent biocompatibility in vivo in terms of rat liver (i.e., serum ALT, AST, and γ-GT) and kidneys (i.e., serum creatinine) function biomarkers.

Recent Research on Hybrid Hydrogels for Infection Treatment and Bone Repair

The repair of infected bone defects (IBDs) is still a great challenge in clinic. A successful treatment for IBDs should simultaneously resolve both infection control and bone defect repair. Hydrogels are water-swollen hydrophilic materials that maintain a distinct three-dimensional structure, helping load various antibacterial drugs and biomolecules. Hybrid hydrogels may potentially possess antibacterial ability and osteogenic activity. This review summarizes the recent progress of different kinds of antibacterial agents (including inorganic, organic, and natural) encapsulated in hydrogels. Several representative hydrogels of each category and their antibacterial mechanism and effect on bone repair are presented. Moreover, the advantages and disadvantages of antibacterial agent hybrid hydrogels are discussed. The challenge and future research directions are further prospected.

Nanomaterials: The New Antimicrobial Magic Bullet

Bacterial infections are a significant cause of mortality and morbidity worldwide, despite decades of use of numerous existing antibiotics and constant efforts by researchers to discover new antibiotics. The emergence of infections associated with antibiotic-resistant bacterial strains, has amplified the pressure to develop additional bactericidal therapies or new unorthodox approaches that can deal with antimicrobial resistance. Nanomaterial-based strategies, particularly those that do not rely on conventional small-molecule antibiotics, offer promise in part due to their ability to dodge existing mechanisms used by drug-resistant bacteria. Therefore, the use of nanomaterial-based formulations has attracted attention in the field of antibiotic therapy. In this Review, we highlight novel and emerging nanomaterial-based formulations along with details about the mechanisms by which nanoparticles can target bacterial infections and antimicrobial resistance. A detailed discussion about types and the activities of nanoparticles is presented, along with how they can be used as either delivery systems or as inherent antimicrobials, or a combination of both. Lastly, we highlight some toxicological concerns for the use of nanoparticles in antibiotic therapies.

Investigation of Cu metal nanoparticles with different morphologies to inhibit SARS-CoV-2 main protease and spike glycoprotein using Molecular Docking and Dynamics Simulation

Nowadays, considering the spread of the coronavirus as a global threat, scientific research on this virus through simulation has been increasing. In this study, effect of Cu nanocluster on prevention and control of disease transmission was examined using molecular docking and molecular dynamics simulation studies on the SARS-CoV-2 main protease and spike glycoprotein. The cytotoxicity of different shapes of copper NPs and resonance changes of their surface plasmons on inactivation of the coronavirus was examined in order to control replication of coronavirus through copper NPs, active site of protease and spike glycoprotein. The simulations results showed that interactions of SARS-CoV-2 main protease and spike glycoprotein target and cylindrical and conical copper NPs ligands were more efficient than spherical copper NPs.

Nearly monodisperse Dy2Sn2O7 nanospheres: hydrothermal synthesis without a template or surfactant and effective sonocatalytic performance

Nearly monodisperse Dy2Sn2O7 nanospheres were prepared by a one-step hydrothermal method, and were used for the ultrasonic catalytic degradation of organic dyes.

Ecotoxicity of as-synthesised copper nanoparticles on soil bacteria

Release of metallic nanoparticles in soil poses a serious threat to the ecosystem as they can affect the soil properties and impose toxicity on soil microbes that are involved in the biogeochemical cycling. In this work, in vitro ecotoxicity of as‐synthesised copper nanoparticles (CuNPs) on Bacillus subtilis (MTCC No. 441) and Pseudomonas fluorescens (MTCC No. 1749), which are commonly present in soil was investigated. Three sets of colloidal CuNPs with identical physical properties were synthesised by chemical reduction method with per batch yield of 0.2, 0.3 and 0.4 gm. Toxicity of CuNPs against these soil bacteria was investigated by MIC (minimum inhibitory concentration), MBC (minimum bactericidal concentration), cytoplasmic leakage and ROS (reactive oxygen species) assay. MIC of CuNPs were in the range of 35–60 µg/ml and 35–55 µg/ml for B. subtilis and P. fluorescens respectively, while their MBC ranged from 40–70 µg/ml and 40–60 µg/ml respectively. MIC and MBC tests reveal that Gram‐negative P. fluorescens was more sensitive to CuNPs as compared to Gram positive B. subtilis mainly due to the differences in their cell wall structure and composition. CuNPs with smaller hydrodynamic size (11.34 nm) were highly toxic as revealed by MIC, MBC tests, cytoplasmic leakage and ROS assays, which may be due to the higher active surface area of CuNPs and greater membrane penetration. Leakage of cytoplasmic components and generation of extra‐cellular oxidative stress by reactive oxygen species (ROS) causes cell death. The present study realizes in gauging the negative impact of inadvertent release of nanoparticles in the environment, however, in situ experiments to know its overall impact on soil health and soil microflora can help in finding solution to combat ecotoxicity of nanoparticles.

CuO Bionanocomposite with Enhanced Stability and Antibacterial Activity against Extended-Spectrum Beta-Lactamase Strains

Worldwide, bacterial resistance to beta-lactam antibiotics is the greatest challenge in public health care. To overcome the issue, metal-based nanoparticles were extensively used as an alternative to traditional antibiotics. However, their unstable nature limits their use. In the present study a very simple, environmentally friendly, one-pot synthesis method that avoids the use of organic solvents has been proposed to design stable, novel nanocomposites. Formulation was done by mixing biogenic copper oxide (CuO) nanomaterial with glycerol and phospholipids isolated from egg yolk in an appropriate ratio at optimum conditions. Characterization was done using dynamic light scattering DLS, Zeta potential, high performance liquid chromatography (HPLC), and transmission electron microscopy (TEM). Further, its antibacterial activity was evaluated against the extended-spectrum beta-lactamase strains based on zone of inhibition and minimal inhibitory concentration (MIC) indices. Results from this study have demonstrated the formulation of stable nanocomposites with a zeta potential of 34.9 mV. TEM results indicated clear dispersed particles with an average of 59.3 ± 5 nm size. Furthermore, HPLC analysis of the egg yolk extract exhibits the presence of phospholipids in the sample and has significance in terms of stability. The newly formed nanocomposite has momentous antibacterial activity with MIC 62.5 μg/mL. The results suggest that it could be a good candidate for drug delivery in terms of bactericidal therapeutic applications.

Quantitative microbiological risk assessment of complex microbial community in Prawn farm wastewater and applicability of nanoparticles and probiotics for eliminating of antibiotic-resistant bacteria

The current review highlighted the quantitative microbiological risk assessment of Vibrio parahaemolyticus in Prawn farm wastewaters (PFWWs) and the applicability of nanoparticles for eliminating antibiotic-resistant bacteria (ARB). The high availability of the antibiotics in the environment and their transmission into human through the food-chain might cause unknown health effects. The aquaculture environments are considered as a reservoir for the antibiotic resistance genes (ARGs) and contributed effectively in the increasing of ABR. The metagenomic analysis is used to explore ARGs in the non-clinical environment. V. parahaemolyticus is among the pathogenic bacteria which are transmitted through sea food causing human acute gastroenteritis due to available thermostable direct hemolysin (tdh), adhesins, TDH related hemolysin (trh). The inactivation of pathogenic bacteria using nanoparticles act by disturbing the cell membrane, interrupting the transport system, DNA and mitochondria damage, and oxidizing the cellular component by reactive oxygen species (ROS). The chloramphenicol, nitrofurans, and nitroimidazole are among the prohibited drugs in fish and fishery product. The utilization of probiotics is the most effective and safe alternative for antibiotics in Prawn aquaculture. This review will ensure public understanding among the readers on how they can decrease the risk of the antimicrobial resistance distribution in the environment.

Antibacterial Activity of Copper Nanoparticles (CuNPs) against a Resistant Calcium Hydroxide Multispecies Endodontic Biofilm

Endodontic treatment reduces the amount of bacteria by using antimicrobial agents to favor healing. However, disinfecting all of the canal system is difficult due to its anatomical complexity and may result in endodontic failure. Copper nanoparticles have antimicrobial activity against diverse microorganisms, especially to resistant strains, and offer a potential alternative for disinfection during endodontic therapy. This study evaluated the antibacterial action of copper nanoparticles (CuNPs) on an ex vivo multispecies biofilm using plaque count compared to the antibacterial activity of calcium hydroxide Ca(OH)₂. There were significant differences between the Ca(OH)₂ and CuNPs groups as an intracanal dressing compared with the CuNPs groups as an irrigation solution (p < 0.0001). An increase in the count of the group exposed to 7 days of Ca(OH)₂ was observed compared to the group exposed to Ca(OH)₂ for 1 day. These findings differ from what was observed with CuNPs in the same period of time. Antibacterial activity of CuNPs was observed on a multispecies biofilm, detecting an immediate action and over-time effect, gradually reaching their highest efficacy on day 7 after application. The latter raises the possibility of the emergence of Ca(OH)₂-resistant strains and supports the use of CuNPs as alternative intracanal medication.

The Association between Selected Dietary Minerals and Mastitis in Dairy Cows-A Review

The aim of this paper is to describe the association between selected dietary minerals and mastitis in dairy cows. Minerals are a group of nutrients with a proven effect on production and reproductive performance. They also strongly affect immune system function. In particular their deficiencies may result in immunosuppression, which is a predisposing factor for udder inflammation occurrence. The role of selected dietary minerals (including calcium, phosphorus, magnesium, selenium, copper and zinc) has been reviewed. Generally, minerals form structural parts of the body; as cofactors of various enzymes they are involved in nerve signaling, muscle contraction and proper keratosis. Their deficiencies lead to reduced activity of immune cells or malfunction of teat innate defense mechanisms, which in turn promote the development of mastitis. Special attention was also paid to minerals applied as nanoparticles, which in the future may turn out to be an effective tool against animal diseases, including mastitis. To conclude, minerals are an important group of nutrients, which should be taken into account on dairy farms when aiming to achieve high udder health status.

Nanoparticles as Novel Emerging Therapeutic Antibacterial Agents in the Antibiotics Resistant Era

Microorganisms are highly resistant to the antibiotics that are commonly used and thus are becoming serious public health problem. There is an urgent need for new approaches to monitor microbial behavior, and hence, nanomaterial can be a very promising solution. Nanotechnology has led to generation of novel antimicrobial agents such as gold, silver, zinc, copper, poly-£-lysine, iron, and chitosan which have shown remarkable potential, demonstrating their applicability as proficient antibiotic agents against various pathogenic bacterial species. The antimicrobial nanoproduct physically kills the organism's cell membranes that prevent the production of drug-resistant microorganisms. These nanosized particles can also be used as diagnostic agents, targeted drug delivery vehicle, noninvasive imaging technologies, and in vivo visual monitoring of tumors angiogenesis. These nanomaterials provide a promising platform for diagnostics, prognostic, drug delivery, and treatment of diseases by means of nanoengineered products/devices. This owes to their small size, prolonged antimicrobial efficacy with insignificant toxicity creating less environmental hazard or toxicity. Scientists address several problems such as health, bioethical problems, toxicity risks, physiological, and pharmaceutical concerns related with the usage of NPs as antimicrobial agents as current research lack adequate data and information on the safe use of certain tools and materials.

Can Copper Products and Surfaces Reduce the Spread of Infectious Microorganisms and Hospital-Acquired Infections?

Pathogen transfer and infection in the built environment are globally significant events, leading to the spread of disease and an increase in subsequent morbidity and mortality rates. There are numerous strategies followed in healthcare facilities to minimize pathogen transfer, but complete infection control has not, as yet, been achieved. However, based on traditional use in many cultures, the introduction of copper products and surfaces to significantly and positively retard pathogen transmission invites further investigation. For example, many microbes are rendered unviable upon contact exposure to copper or copper alloys, either immediately or within a short time. In addition, many disease-causing bacteria such as E. coli O157:H7, hospital superbugs, and several viruses (including SARS-CoV-2) are also susceptible to exposure to copper surfaces. It is thus suggested that replacing common touch surfaces in healthcare facilities, food industries, and public places (including public transport) with copper or alloys of copper may substantially contribute to limiting transmission. Subsequent hospital admissions and mortality rates will consequently be lowered, with a concomitant saving of lives and considerable levels of resources. This consideration is very significant in times of the COVID-19 pandemic and the upcoming epidemics, as it is becoming clear that all forms of possible infection control measures should be practiced in order to protect community well-being and promote healthy outcomes.

Nanomaterials as drug delivery systems with antibacterial properties: current trends and future priorities

Introduction:Despite extensive advances in the production and synthesis of antibiotics, infectious diseases are one of the main problems of the 21st century due to multidrug-resistant (MDR) distributing in organisms. Therefore, researchers in nanotechnology have focused on new strategies to formulate and synthesis the different types of nanoparticles (NPs) with antimicrobial properties.Areas covered:The present review focuses on nanoparticles which are divided into two groups, organic (micelles, liposomes, polymer-based and lipid-based NPs) and inorganic (metals and metal oxides). NPs can penetrate the cell wall then destroy permeability of cell membrane, the structure and function of cell macromolecules by producing of reactive oxygen species (ROS) and eventually kill the bacteria. Moreover, their characteristics and mechanism in various bacteria especially MDR bacteria and finally their biocompatibility and the factors affecting their activity have been discussed.Expert opinion:Nanotechnology has led to higher drug absorption, targeted drug delivery and fewer side effects. NPs can overcome MDR through affecting several targets in the bacteria cell and synergistically increase the effectiveness of current antibiotics. Moreover, organic NPs with regard to their biodegradability and biocompatibility characteristics can be suitable agents for medical applications. However, they are less stable in environment in comparison to inorganic NPs.

Size-Specific Copper Nanoparticle Cytotoxicity Varies between Human Cell Lines

Commercially available copper nanoparticles of three different sizes were tested for cytotoxicity against three human cell lines using four different cytotoxicity assays. This array of data was designed to elucidate trends in particle stability, uptake, and cytotoxicity. The copper nanoparticles are not stable in cell culture media, and rapid changes over the time course of the assays play a critical role in the measured endpoints. Typically, the 40-60 nm particles tested were more cytotoxic than either smaller or larger particles. These particles were also taken up more readily by cells and exhibited different stability dynamics in cell culture media. This provides a good correlation between total cellular uptake of copper and cytotoxicity that may be directly linked to particle stability, though it is unclear why the intermediate-sized particles exhibited these unique properties when compared with both larger and smaller particles.

Filtration Materials Modified with 2D Nanocomposites-A New Perspective for Point-of-Use Water Treatment

Point-of-use (POU) water treatment systems and devices play an essential role in limited access to sanitary safe water resources. The filtering materials applied in POU systems must effectively eliminate contaminants, be readily produced and stable, and avoid secondary contamination of the treated water. We report an innovative, 2D Ti3C2/Al2O3/Ag/Cu nanocomposite-modified filtration material with the application potential for POU water treatment. The material is characterized by improved filtration velocity relative to an unmodified reference material, effective elimination of microorganisms, and self-disinfecting potential, which afforded the collection of 99.6% of bacteria in the filter. The effect was obtained with nanocomposite levels as low as 1%. Surface oxidation of the modified material increased its antimicrobial efficiency. No secondary release of the nanocomposites into the filtrate was observed and confirmed the stability of the material and its suitability for practical application in water treatment.

Inorganic nanomaterials for fighting surface and airborne pathogens and viruses

Nowadays, the deadly viruses (including the latest coronavirus) and pathogens transmission became the major concern worldwide. Efforts have been made to combat with these fatal germs transmitted by the airborne, human-to-human contacts and contaminated surfaces. Thus, the antibacterial and antiviral materials have been widely researched. Meanwhile, the development of diverse nanomaterials with the antiviral traits provided several benefits to counter the threats from the surface and airborne viruses especially during the Covid-19 pandemic. Based on these facts, this paper overviewed the advantages of various nanomaterials that can disinfect and deactivate different lethal viruses transmitted through the air and surfaces. The past development, recent progress, future trends, environmental impacts, biocidal effects and prospects of these nanomaterials for the antiviral coating applications have been emphasized.

Micro-structured copper and nickel metal foams for wastewater disinfection: proof-of-concept and scale-up

It is necessary to disinfect treated wastewater prior to discharge to reduce exposure risks to humans and the environment. The currently practiced wastewater disinfection technologies are challenged by toxic by-products, chemicals and energy demand, a range of effectiveness limitations, among other concerns. An effective, eco-friendly, and energy-efficient alternative disinfection technique is desirable to modernize and enhance wastewater treatment operations. Copper and nickel micro-structured metal foams, and a conventional copper mesh, were evaluated as disinfecting surfaces for treating secondary-treated wastewater contaminated with coliform bacteria. The micro-structured copper foam was adopted for scale-up study, due to its stable and satisfactory bactericidal performance obtained over a wide range of bacterial concentrations and metal-to-liquid ratios. Three scales of experiments, using two types of reactor designs, were performed using municipal wastewater to determine the optimal scale-up factors: small lab-scale batch reactor, intermediate lab-scale batch reactor, and pilot-scale continuous tubular reactor experiments. The performance was evaluated with the aim of minimizing metal material requirement with respect to bactericidal efficiency and leaching risks at all scales. Copper foam, at or above optimal conditions, consistently inactivated over 95 % of total coliforms, fecal coliforms and E.coli in wastewater at various scales, and leachate copper concentrations were determined to be below Canadian guideline values for outfall. This study successfully implemented the "structure" strategy of process intensification, and opens up the possibility to apply micro-structured copper foam in a range of other water disinfection systems, from pre-treatment to point-of-use, and should thus become a topic of further research.

Antimicrobial and Biocompatible Polycaprolactone and Copper Oxide Nanoparticle Wound Dressings against Methicillin-Resistant Staphylococcus aureus

One of the major health problems linked to methicillin-resistant Staphylococcus aureus (MRSA) is severe diabetic foot ulcers (DFU), which are associated with hospital-acquired infections, lower limb amputations and emerging resistance to the current antibiotics. As an alternative, this work aims to develop a biodegradable and biocompatible material with antimicrobial capacity to prevent DFU. This was achieved by producing active polymeric films with metallic nanoparticles dispersed through a polycaprolactone (PCL) dressing. First, the antimicrobial activity of copper oxide nanoparticles (CuONPs) was tested by the microdilution method, selecting the lowest concentration that has an inhibitory effect on MRSA. Then, active PCL films were prepared and characterized in terms of their physicochemical properties, antimicrobial performance, cytotoxicity, genotoxicity and hemocompatibility. Active films had chemical and thermal properties like the ones without the antimicrobial agents, which was confirmed through FTIR, Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) analysis. In relation to antimicrobial activity, active PCL films inhibited MRSA growth when treated with CuONPs at a concentration of 0.07% (w/w). After exposure to the active film extracts, human foreskin fibroblast cells (ATCC^® SCRC1041™) (HFF-1) exhibited a cell viability average above 80% for all treatments and no DNA damage was found. Finally, PCL films with 0.07% (w/w) CuONPs proved to be hemocompatible, and none of the films evaluated had red blood cell breakage greater than 5%, being within the acceptable limits established by the International Organization for Standardization ISO 10993-4:2002.

Synthesis and characterization of a silver nanoparticle-containing polymer composite with antimicrobial abilities for application in prosthetic and orthotic devices

Background

The presence of skin problems in patients using external lower limb prosthesis is recurrent. This has generated the need to develop interfaces for prosthesis with the ability to control microbial growth. Silver nanoparticles (AgNPs) have been implemented in the development of biomaterials because of their high antimicrobial activity. This article discusses the development of an AgNP-containing polymer composite with antimicrobial activity for developing prosthetic liners.

Methods

AgNPs were synthesized using a photochemical method and certain physicochemical properties were characterized. Furthermore, the antimicrobial activity of AgNPs against Staphylococcus aureus ATCC 25923 and methicillin-resistant Staphylococcus aureus (MRSA), was assessed on the basis of their minimum inhibitory concentrations (MICs). AgNPs were incorporated into a silicon elastomer to assess certain physicomechanical properties, antimicrobial activity and cytotoxic effect of the material.

Results

The maximum antimicrobial activity of the material against Staphylococcus aureus ATCC 25923 and MRSA was 41.58% ±2.97% at AgNP concentration of 32.98 μg/mL and 14.85% ±5.94% at AgNP concentration of 16.49 μg/mL, respectively. Additionally, the material exhibited tensile yield strength, rupture tensile strength, and tensile modulus of elasticity of 0.70 - 1.10 MPa, 0.71–1.06 MPa, and 0.20 - 0.30 MPa, respectively. The mechanical characteristics of the material were within the acceptable range for use in external lower limb prosthetic and orthotic interfaces.

Conclusions

It was possible to incorporate the AgNPs in a silicone elastomer, finding that the composite developed presented antimicrobial activity against Staphylococcus aureus ATCC 25923 and MRSA when compared to non-AgNP material samples.