In Vivo and In Vitro Assessments of the Antibacterial Potential of Chitosan-Silver Nanocomposite Against Methicillin-Resistant Staphylococcus aureus-Induced Infection in Rats

Friedelin: A natural compound exhibited potent antibacterial, anti-inflammatory, and wound healing properties against MRSA-infected wounds

Methicillin-resistant Staphylococcus aureus (MRSA) is primarily recognized as a pathogen responsible for skin, soft tissue, and multiple organs infection. The colonization of the skin and mucous membranes by hypervirulent resistant bacteria like MRSA during hospitalization significantly contributes to life-threatening conditions. Friedelin (FRN) is a pentacyclic triterpene (C30H50O) isolated from Euphorbia grantii Oliv. The current work aims to determine the efficacy of FRN against MRSA-infected wounds in mice besides the in vitro study to evaluate its bactericidal activity. The in vitro study revealed that FRN was strongly active against MRSA which had a wide zone of MRSA growth inhibition and promising minimum inhibitory concentration (MIC). Moreover, FRN downregulated the major virulence genes seb and icaD, responsible for the production of staphylococcal enterotoxin SED and biofilm formation, respectively in contrast to the untreated group. The dressing of MRSA-infected wound with 40 ppm FRN significantly reduced the wound size and bacterial count and accelerated the process of wound healing which had a higher immune expression of both VEGF (vascular endothelial growth factor) and α-SMA (alpha smooth muscle actin) compared with other treated groups. Additionally, FRN could reduce the inflammatory response of MRSA in a dose-dependent manner by downregulating the TNF-α (tumor necrosis factor-α) and PGS-2 (prostaglandin synthase-2) gene expression levels. FRN is effective against MRSA-infected wounds via its potent bactericidal and anti-inflammatory activities that accelerate angiogenesis and wound maturation.

Oral supplementation of curcumin-encapsulated chitosan nanoconjugates as an innovative strategy for mitigating nickel-mediated hepatorenal toxicity in rats

Nickel pollution adversely affects human health and causes various disorders, mainly hepatic and renal dysfunction. The present work focused on a comparative evaluation of the pure form of curcumin (CU) with curcumin-encapsulated chitosan nanoconjugates (CS/CU NCs), on mitigation of the delirious effects of Ni on hepatorenal tissue. Forty-two male rats were allocated into 6 groups (n = 7 for each) as follows: (1) control, (2) CU, (3) CS/CU NCs, (4) Ni, (5) Ni + CU, (6) Ni + CS/CU NCs. After 30 days, blood and tissue (liver and kidneys) were collected to measure hepatorenal biomarkers, oxidant/antioxidant balance, inflammatory gene expression, liver and kidney histopathology, and immunohistochemistry. Results revealed disruption of hepatorenal functions, oxidative stress, and inflammatory markers at biochemical and molecular levels associated with severe hepatorenal histopathological alterations and abnormal immunohistochemical tissue expression for caspase-3 and cyclooxygenase-2. On the contrary, the treatment of Ni-intoxicated rats with CS/CU NCs markedly mitigated the adverse effect of Ni on hepatorenal tissue via regulation of oxidative stress, inflammatory, and apoptotic markers. The present study provides a novel nanoformulation for curcumin using CS NPs encapsulation that selectively targets the injured cells and improves the beneficial effect of CU via enhancing the antioxidant activity and regulating both inflammatory and apoptotic markers.

Ultrastructural effects of Staphylococcus aureus toxicity on albino mice kidney

Staphylococcus aureus (S. aureus) is a prominent infectious etiological agent in humans, dairy animals, and camels. Camel milk has all the nutrients which are nutritious and advantageous to the growth of S. aureus that dominates most bacterial species. So, the present work was designed to investigate the effect of certain toxin gene of S. aureus bacteria isolated from raw camel milk on the fine structure of mice kidneys. Two toxin genes of S. aureus were identified and described through PCR using 23s rRNA primer for 23s rRNA gene. In addition, the effect of the isolated S. aureus bacteria, especially those carrying the gene "tst" was studied on the ultrastructure of mice kidney. Twenty male albino mice were allocated into 2 groups, control group and infected group (orally administered with a single dosage of S. aureus aqueous solutions from camel milk at a concentration of 5 × 108 colony forming unit/0.1 mL for three days). Infection of mice with S. aureus resulted in vacuolation, necrosis, and degeneration of tubular epithelial cells, intertubular congestion and inflammation, as well as dilatation and congestion of glomeruli. Therefore, this current study most likely indicates that camel milk infected with S. aureus has a significant and clear impact in inducing symptoms of kidney failure in communities that use these dairy products without health supervision, especially nomadic and pastoral communities.

Toxicological screening of zinc oxide nanoparticles in mongrel dogs after seven days of repeated subcutaneous injections

Zinc oxide nanoparticles (ZnO NPs) have recently been applied in various veterinary and medical fields, however, the toxicological evaluations of these NPs in dogs are lacking. Therefore, the current study is designed to assess the impact of exposure to daily subcutaneous (SC) injections of ZnO NPs at different concentrations on various organs of mongrel dogs. Nine dogs were randomly divided into three groups (n = 3 for each) as follows: group (1) served as the control group, whereas groups (2&3) received SC injections of 50 and 100 ppm ZnO NPs (8 and 16 μg/kg bwt), respectively, once/day for 7 days. Our results revealed that ZnO NPs disrupted the oxidant/antioxidant balance in the lungs, liver, and kidneys of dogs in a dose-dependent manner. ZnO NPs induced dose-dependent radiological, ultrasonographical, and histopathological alterations in various organs especially lungs, spleen, liver, and kidneys along with disturbance in both liver and kidney biomarkers levels. Most organs of both ZnO NPs receiving groups displayed strong caspase-3 protein expression. Additionally, it upregulates the transcriptase levels of TNF-α and VEGF, as well as downregulates the antiapoptotic gene IL-10 in lung, kidney, and liver tissue homogenates. It was concluded that the daily SC injections of dogs with ZnO NPs at concentrations of 50 and 100 ppm caused extensive oxidative stress damage in various organs which provoked serious pathological processes such as apoptosis and inflammation.

Fabrication and antimicrobial properties of novel meropenem-honey encapsulated chitosan nanoparticles against multiresistant and biofilm-forming Staphylococcus aureus as a new antimicrobial agent

BACKGROUND

Honey exhibits a broad spectrum of antibacterial activity against Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) ones. Chitosan (Cs) is a mucoadhesive polymer that also has antibacterial properties. Special attention has been paid to the design of polymeric nanoparticles (NPs) as new nano drug delivery systems to overcome bacterial resistance and its problems.

OBJECTIVES

The aim of the present study is to synthesize Cs-meropenem NPs with/without honey as an antibiofilm and antibacterial agent to inhibit Staphylococcus aureus.

METHODS

This study synthesized meropenem and honey-loaded Cs nanogels and subsequently characterized them by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), and DLS-zeta potential. Using the broth microdilution and crystal violet assays, the antibacterial and antibiofilm activity of meropenem and honey-loaded Cs nanogel, free meropenem, free honey, and free Cs NPs were investigated in vitro against MRSA strains. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) was also used to test the cytotoxicity of several Cs-NPs compound against the HEK-293 regular cell line.

RESULTS

The average size of meropenem and honey-Cs-NPs was reported to be 119.885 nm, and encapsulation efficiency was 88.33 ± 0.97 with stability up to 60 days at 4°C. The NPs showed enhanced antibiofilm efficacy against S. aureus at sub-minimum inhibitory concentrations. Additionally, the cytotoxicity of meropenem and honey-encapsulated Cs against the HEK-293 normal cell line was insignificant.

CONCLUSIONS

Our findings suggested that meropenem and honey-Cs-NPs might be potential antibacterial and antibiofilm materials.

Chitosan-Loaded Lagenaria siceraria and Thymus vulgaris Potentiate Antibacterial, Antioxidant, and Immunomodulatory Activities against Extensive Drug-Resistant Pseudomonas aeruginosa and Vancomycin-Resistant Staphylococcus aureus: In Vitro and In Vivo Approaches

Antimicrobial resistance poses considerable issues for current clinical care, so the modified use of antimicrobial agents and public health initiatives, coupled with new antimicrobial approaches, may help to minimize the impact of multidrug-resistant (MDR) bacteria in the future. This study aimed to evaluate the antimicrobial, antioxidant, and immunomodulatory activities of Lagenaria siceraria, Thymus vulgaris, and their chitosan nanocomposites against extensive drug-resistant (XDR) Pseudomonas aeruginosa and vancomycin-resistant Staphylococcus aureus (VRSA) using both in vitro and in vivo assays. The in vitro antimicrobial susceptibilities of P. aeruginosa and VRSA strains revealed 100% sensitivity to imipenem (100%). All P. aeruginosa strains were resistant to cefoxitin, cefepime, trimethoprim + sulfamethoxazole, and fosfomycin. However, S. aureus strains showed a full resistance to cefoxitin, amoxicillin, ampicillin, erythromycin, chloramphenicol, and fosfomycin (100% each). Interestingly, all S. aureus strains were vancomycin-resistant (MIC = 32-512 μg/mL), and 90% of P. aeruginosa and S. aureus strains were XDR. The antimicrobial potential of Lagenaria siceraria and Thymus vulgaris nanocomposites with chitosan nanoparticles demonstrated marked inhibitory activities against XDR P. aeruginosa and VRSA strains with inhibition zones' diameters up to 50 mm and MIC values ranging from 0.125 to 1 μg/mL and 1 to 8 μg/mL, respectively. The results of the in vivo approach in male Sprague Dawley rats revealed that infection with P. aeruginosa and S. aureus displayed significant changes in biochemical, hematological, and histopathological findings compared to the negative control group. These values returned to the normal range after treatment by chitosan nanoparticles, either loaded with Lagenaria siceraria or Thymus vulgaris. Real-time quantitative polymerase chain reaction (RT-qPCR) findings presented significant upregulation of the relative expression of the IL10 gene and downregulation of the IFNG gene throughout the experimental period, especially after treatment with chitosan nanoparticles loaded either with Lagenaria siceraria or Thymus vulgaris in comparison to the positive control groups. In conclusion, this is the first report suggesting the use of Lagenaria siceraria and Thymus vulgaris nanocomposites with chitosan nanoparticles as a promising contender for combating XDR P. aeruginosa and VRSA infections as well as a manager for inflammatory situations and oxidative stress-related disorders.

Research progress on antibacterial applications of metal-organic frameworks and their biomacromolecule composites

With the extensive use of antibiotics, resulting in increasingly serious problems of bacterial resistance, antimicrobial therapy has become a global concern. Metal-organic frameworks (MOFs) are low-density porous coordination materials composed of metal ions and organic ligands, which can form composite materials with biomacromolecules such as proteins and polysaccharides. In recent years, MOFs and their derivatives have been widely used in the antibacterial field as efficient antibacterial agents. This review offers a detailed summary of the antibacterial applications of MOFs and their composites, and the different synthesis methods and antibacterial mechanisms of MOFs and MOF-based composites are briefly introduced. Finally, the challenges and prospects of MOFs-based antibacterial materials in the rapidly developing medical field were briefly discussed. We hope this review will provide new strategies for the medical application of MOFs-based antibacterial materials.

Chitosan coating silver nanoparticles as a promising feed additive in broilers chicken

The present study aimed to evaluate the potential of chitosan coating silver nanoparticles to enhance the growth performance and immune status of broilers without inducing oxidative stress-related pathological lesions in any organs or leaving residues of silver in the edible parts. Five clusters of Cobb one-day-old chicks (n = 10/group in each replication) were given oral therapy, once a week for 36 days as follows: (1) distilled water, (2, 3) 0.5- and 5 ppm silver nanoparticles (AgNPs), respectively, (4, 5) 0.5- and 5 ppm chitosan/silver nanoconjugates (CS/Ag-NCs), respectively. The results demonstrated a marked elevation in the body weight gain with a decline in the food conversion ratio and marked improvement in feeding and drinking behavior of all nanoparticles treated groups, but higher in CS/Ag-NCs groups than AgNPs groups and control group. In contrast to the 0.5 ppm AgNPs receiving group, the group receiving 5 ppm AgNPs noticed remarkable histological changes in some organs, including the liver, kidneys, spleen, and heart. Moreover, the administration of CS/Ag-NCs at two dosage levels didn't influence any histological changes. The AgNPs groups' antibody titers against the ND and AI viruses were almost identical to those of the control group. Otherwise, CS/Ag-NCs groups recorded the highest antibody titers. Additionally, there was a significant increase in silver content in most edible organs of AgNPs groups at a dosage level of 5 ppm. Otherwise, the coating of AgNPs by CSNPs could decrease the aggregation of silver in the biological organs. Thus, we recommend utilizing 0.5 ppm CS/Ag-NCs in broiler farms to promote their growth performance and strengthen their immune defense.

Chitosan nanoparticle encapsulation increased the prophylactic efficacy of Lactobacillus plantarum RM1 against AFM1-induced hepatorenal toxicity in rats

Aflatoxin M1 (AFM1) is a significant contaminant of food, particularly dairy products and can resist various industrial processes. Several probiotic strains like Lactobacillus plantarum are known to reduce aflatoxin availability in synthetic media and some food products. The current work investigated the possible chitosan coating prophylactic efficacy of Lactobacillus plantarum RM1 nanoemulsion (CS-RM1) against AFM1-induced hepatorenal toxicity in rats. Twenty-eight male Wistar rats were divided into four groups (n = 7) as follows: group 1 received normal saline, group 2 received CS-RM1 (1mL contains 6.7 × 1010 CFU), group 3 received AFM1 (60 µg/kg bwt), and group 4 received both CS-RM1(1 mL contains 6.7 × 1010 CFU) and AFM1 (60 µg/kg bwt). All receiving materials were given to rats daily via oral gavage for 28 days. AFM1 caused a significant elevation in serum levels of ALT, AST, ALP, uric acid, urea, and creatinine with marked alterations in protein and lipid profiles. Additionally, AFM1 caused marked pathological changes in the liver and kidneys, such as cellular necrosis, vascular congestion, and interstitial inflammation. AFM1 also increased the MDA levels and decreased several enzymatic and non-enzymatic antioxidants. Liver and kidney sections of the AFM1 group displayed strong caspase-3, TNF-α, and iNOS immunopositivity. Co-treatment of CS-RM1 with AFM1 significantly lowered the investigated toxicological parameter changes and markedly improved the microscopic appearance of liver and kidneys. In conclusion, AFM1 induces hepatorenal oxidative stress damage via ROS overgeneration, which induces mitochondrial caspase-3-dependent apoptosis and inflammation. Furthermore, CS-RM1 can reduce AFM1 toxicity in both the liver and kidneys. The study recommends adding CS-RM1 to milk and milk products for AFM1-elimination.

Nanomedicine for drug resistant pathogens and COVID-19 using mushroom nanocomposite inspired with bacteriocin – A Review

Multidrug resistant (MDR) pathogens have become a major global health challenge and have severely threatened the health of society. Current conditions have gotten worse as a result of the COVID-19 pandemic, and infection rates in the future will rise. It is necessary to design, respond effectively, and take action to address these challenges by investigating new avenues. In this regard, the fabrication of metal NPs utilized by various methods, including green synthesis using mushroom, is highly versatile, cost-effective, eco-compatible, and superior. In contrast, biofabrication of metal NPs can be employed as a powerful weapon against MDR pathogens and have immense biomedical applications. In addition, the advancement in nanotechnology has made possible to modify the nanomaterials and enhance their activities. Metal NPs with biomolecules composite to prevents their microbial adhesion and kills the microbial pathogens through biofilm formation. Bacteriocin is an excellent antimicrobial peptide that works well as an augmentation substance to boost the antimicrobial effects. As a result, we concentrate on the creation of new, eco-compatible mycosynthesized metal NPs with bacteriocin nanocomposite via electrostatic, covalent, or non-covalent bindings. The synergistic benefits of metal NPs with bacteriocin to combat MDR pathogens and COVID-19, as well as other biomedical applications, are discussed in this review. Moreover, the importance of the adverse outcome pathway (AOP) in risk analysis of manufactured metal nanocomposite nanomaterial and their future possibilities also discussed.

Metal-based nanomaterials and nanocomposites as promising frontier in cancer chemotherapy

Cancer is a disease associated with complex pathology and one of the most prevalent and leading reasons for mortality in the world. Current chemotherapy has challenges with cytotoxicity, selectivity, multidrug resistance, and the formation of stemlike cells. Nanomaterials (NMs) have unique properties that make them useful for various diagnostic and therapeutic purposes in cancer research. NMs can be engineered to target cancer cells for early detection and can deliver drugs directly to cancer cells, reducing side effects and improving treatment efficacy. Several of NMs can also be used for photothermal therapy to destroy cancer cells or enhance immune response to cancer by delivering immune-stimulating molecules to immune cells or modulating the tumor microenvironment. NMs are being modified to overcome issues, such as toxicity, lack of selectivity, increase drug capacity, and bioavailability, for a wide spectrum of cancer therapies. To improve targeted drug delivery using nano-carriers, noteworthy research is required. Several metal-based NMs have been studied with the expectation of finding a cure for cancer treatment. In this review, the current development and the potential of plant and metal-based NMs with their effects on size and shape have been discussed along with their more effective usage in cancer diagnosis and treatment.

Nanotechnology: a contemporary therapeutic approach in combating infections from multidrug-resistant bacteria

In the 20th century, the discovery of antibiotics played an essential role in the fight against infectious diseases, including meningitis, typhoid fever, pneumonia and Mycobacterium tuberculosis. The development of multidrug resistance in microflora due to improper antibiotic use created significant public health issues. Antibiotic resistance has increased at an alarming rate in the past few decades. Multidrug-resistant bacteria (superbugs) such as methicillin-resistant Staphylococcus aureus (MRSA) as well as drug-resistant tuberculosis pose serious health implications. Despite the continuous increase in resistant microbes, the discovery of novel antibiotics is constrained by the cost and complexities of discovery of drugs. The nanotechnology has given new hope in combating this problem. In the present review, recent developments in therapeutics utilizing nanotechnology for novel antimicrobial drug development are discussed. The nanoparticles of silver, gold and zinc oxide have proved to be efficient antimicrobial agents against multidrug-resistant Klebsiella, Pseudomonas, Escherichia Coli and MRSA. Using nanostructures as carriers for antimicrobial agents provides better bioavailability, less chances of sub-therapeutic drug accumulation and less drug-related toxicity. Nanophotothermal therapy using fullerene and antibody functionalized nanostructures are other strategies that can prove to be helpful.

Progress and prospects of nanomaterials against resistant bacteria

Drug-resistant bacterial infections are increasingly heightening, which lead to more severe illness, higher cost of treatment and increased risk of death. Nanomaterials-based therapy, an "outrider", serving as a kind of innovative antimicrobial therapeutics, showing promise in replacing antimicrobial agents and enhancing the activity of antibiotics, generally bases on the various inorganic and/or organic materials. When the size of those materials is below to a certain nano-level and the content of nanomaterials is above a certain amount, they are lethal to the resistant bacteria, which bypass the traditional bacterial resistance mechanisms. This review highlights the effect of nanomaterials in combating extracellular/intracellular bacteria and eradicating biofilms. Based on the studies searched on the Web of Science through relevant keywords, this review article starts with analyzing the current situation, resistance mechanisms, and treatment difficulties of bacteria resistance. Then, the efficacy of nanomaterials against resistant bacteria and their mechanisms (e.g., physical impairment, biofilm lysis, regulating bacterial metabolism, protein and DNA replication as well as enhancing the antibiotics concentration in infected cells) are collected. Lastly, the factors affecting the antibacterial efficacy are argued from the side of nanomatrials and bacterium, which followed by the emerging challenges and recent perspectives of achieving higher targeting released nanomaterials as antibacterial therapeutics.

Biological investigation of a novel nanocomposite based on functionalized graphene oxide nanosheets with pectin, silk fibroin and zinc chromite nanoparticles

For biotechnology applications, a novel nanobiocomposite was synthesized based on modification of graphene oxide (GO) by extracted silk fibroin (SF), natural polymer pectin (Pec) and zinc chromite (ZnCr₂O₄) nanoparticles (NPs). The structure and properties of hybrid nanobiocomposite GO-Pec/SF/ZnCr₂O₄ such as thermal stability, less toxicity, biocompatibility, antibacterial, and biodegradable were proved by using field emission scanning electron microscope (FE-SEM), Fourier-transformed infrared (FT-IR), Energy dispersive X-ray spectroscopy (EDS), thermal gravimetric analysis (TGA), and X-Ray diffraction (XRD). According to the biological features of substances, the GO-Pec/SF/ZnCr₂O₄ nanobiocomposite shows perfect results in MTT (83.71 %) and Hemolysis (16.52 %) assays. accordingly, mentioned properties of this nanobiocomposite can be used as a scaffold for medical applications.

Insights overview on the possible protective effect of chitosan nanoparticles encapsulation against neurotoxicity induced by carbendazim in rats

Carbendazim (CBZ) contamination of food and water is a principal factor in many negative impacts on public health. Nanoencapsulation of agrochemicals by nontoxic polymers as chitosan nanoparticles (CS-NPs) is one of the most applications of nanotechnology in agriculture. Despite its many advantages, such as it provides controlled release property, more stability and solubility of the active ingredient, it is not authorized to be used in the market because there are no adequate studies on the nano pesticides induced toxicity on experimental animals. So, we aim to study the possible impacts of CBZ-loading CS-NPs on the whole brain of rats and to explain its mechanism of action. 20 male Wistar rats were partitioned into 4 groups as follows: Group (1), normal saline; group (2), 5 mg/kg CS-NPs; group (3), 300 mg/kg CBZ; group (4) 300 mg/kg CS/CBZ-NCs. After 28 days, some neurobehavioral parameters were assessed to all rats then euthanization was done to collect the brain. Our results revealed that CBZ prompted neurotoxicity manifested by severe neurobehavioral changes and a significant increase of MDA with a decrease of GSH and CAT in brain tissue. In addition, there were severe neuropathological alterations confirmed by immunohistochemistry which showed strong bax, GFAP, and TNF-ὰ protein expression in some brain areas. CBZ also induced apoptosis manifested by up-regulation of JNK and P53 with down-regulation of Bcl-2 in brain tissue. Otherwise, encapsulation of CBZ with CS-NPs could reduce CBZ-induced neurotoxicity and improve all studied toxicological parameters. We recommend using CBZ-loading CS-NPs as an alternative approach for fungicide application in agricultural and veterinary practices but further studies are needed to ensure its safety on other organs.

Effect of Titanium Dioxide and Silver Nanoparticles on Mitochondrial Dynamics in Mouse Testis Tissue

This study was performed to investigate whether the toxicity of nanoparticles (Ag NPs or TiO₂ NPs) affected mitochondrial dynamics (mitochondrial fusion and fission mechanisms) in testicular cells of mice. Animals were assigned into three groups (ten mice per group): control group (distilled water), TiO₂ NP group (5 mg/kg per dose), and Ag NP group (5 mg/kg per dose). NPs were administered intravenously (via tail vein) to mice with 3-day intervals. To determine the possible toxic effect of NPs on mitochondrial dynamics, the expression levels of mitochondrial fission (Drp1)- and fusion (Mfn1, Mfn2, OPA1)-related genes were analyzed. The results showed that both Ag NPs and TiO₂ NPs entered the testis via the blood-testis barier and accumulated in mouse testis tissue. Experiments showed that administration of Ag NPs neither alters testicular weight and testicular index nor causes significant toxic effect on sperm parameters. RT-PCR analysis demonstrated that Ag NP treatment did not disrupt mitochondrial dynamics in testicular cells. Conversely, administration of TiO₂ NPs (anatase, < 25 nm) decreased the sperm motility and the percentages of sperms with swollen tail. Furthermore, RT-PCR and western blot analyses showed that TiO₂ NPs disrupted mitochondrial dynamics by causing excess mitochondrial fission (excess expression of Drp1 gene and DRP1 protein). This is the first report on the toxicity of nanoparticles on mitochondrial dynamics (fusion and fission mechanisms) in testicular cells.

Advances in Nanostructures for Antimicrobial Therapy

Microbial infections caused by a variety of drug-resistant microorganisms are more common, but there are fewer and fewer approved new antimicrobial chemotherapeutics for systemic administration capable of acting against these resistant infectious pathogens. Formulation innovations of existing drugs are gaining prominence, while the application of nanotechnologies is a useful alternative for improving/increasing the effect of existing antimicrobial drugs. Nanomaterials represent one of the possible strategies to address this unfortunate situation. This review aims to summarize the most current results of nanoformulations of antibiotics and antibacterial active nanomaterials. Nanoformulations of antimicrobial peptides, synergistic combinations of antimicrobial-active agents with nitric oxide donors or combinations of small organic molecules or polymers with metals, metal oxides or metalloids are discussed as well. The mechanisms of actions of selected nanoformulations, including systems with magnetic, photothermal or photodynamic effects, are briefly described.

Characterization, optimization, and evaluation of preservative efficacy of carboxymethyl cellulose/hydromagnesite stromatolite bio-nanocomposite

Currently, researchers are focusing on the development of nano-additive preservatives during the worldwide COVID-19 pandemic. This research aimed to constitute a small sized preservative nano-formulation which emerges from the biopolymer carboxymethyl cellulose (a green stabilizing agent) and hydromagnesite stromatolite (a fossilized natural additive). In this study, we investigated the optimization of the experimental design of carboxymethyl cellulose/hydromagnesite stromatolite (CMC/HS) bio-nanocomposites using a green and one-step sonochemical method at room temperature. In addition, we constructed a mathematical model which relates the intrinsic viscosity with all operating variables, and we carried out statistical error analysis to assess the validity of the proposed model. The characterization and chemical functional groups of CMC/HS bio-nanocomposites were determined by different advanced techniques such as SEM, HRTEM, DLS, FTIR, XRD, and BET. The challenge test was used to show the preservative efficacy of CMC/HS bio-nanocomposites against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, and Aspergillus brasiliensis. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltrazolium bromide (MTT) assay was performed on L929 cells to evaluate the in vitro cytotoxicity of CMC/HS bio-nanocomposites. According to the results, we showed that the synthesized CMC/HS bio-nanocomposites have no cytototoxic effects on L929 fibroblast cells and could be considered to be an alternative green nano-additive preservative against pathogenic microorganisms.

Assessment of the Antibacterial Potential of Biosynthesized Silver Nanoparticles Combined with Vancomycin Against Methicillin-Resistant Staphylococcus aureus-Induced Infection in Rats

Methicillin-resistant Staphylococcus aureus (MRSA) is considered one of the most serious multidrug-resistant bacteria worldwide. MRSA resistance to methicillin antibiotics made vancomycin, the acceptable treatment option. Silver nanoparticles (Ag-NPs) are among the well-known antibacterial substances showing multimode antibacterial action. Therefore, Ag-NPs are appropriate applicants for use in combination with vancomycin in order to augment its antibacterial action. This study aimed to biosynthesize silver nanoparticles and to evaluate its antibacterial activity against MRSA alone and when combined with vancomycin both in vitro and in vivo. Agaricus bisporus is used to reduce the silver nitrate salts in solution to yield silver nanoparticles which was characterized by UV-visible spectrophotometric analysis that shows maximum absorption at 420 nm as a preliminary confirmation for nanoparticles synthesis, Energy-Dispersive Analysis of X-ray (EDX) which confirms the crystalline nature of silver nanoparticles and transmission electron microscopy (TEM) image shows the particles in spherical form with mean size 27.45 nm. The synthesized silver nanoparticles were tested for antibacterial activity against MRSA, and the synergetic effects of the combination of silver nanoparticles and vancomycin were evaluated. The results showed a strong synergistic antibacterial effect between Ag-NPs and vancomycin in vitro with fractional inhibitory concentration 0.37 and in vivo against MRSA strain. The result revealed that mycosynthesized silver nanoparticles (NPs) enhance the in vitro and in vivo antibacterial activity of vancomycin against MRSA. These results suggested that sliver nanoparticles have an effective antibacterial activity against MRSA count, histopathology, and liver enzymes as well as protective immune response specially when combined with vancomycin in the lungs of infected rats with MRSA.

Ameliorative effect of ZnO-NPs against bioaggregation and systemic toxicity of lead oxide in some organs of albino rats

Lead is one of the major environmental pollutions worldwide, particularly in developing countries. Though, various occupational and public health measures have been undertaken to control lead exposure. The present study is designed to investigate the role of zinc oxide nanoparticles (ZnO-NPs) to reduce the bioaggregation of lead in the brain, liver, and kidneys and prevent these organ oxidative damage and apoptosis. Twenty male Wistar rats were grouped into 4 gatherings and exposed to the following materials daily on the skin for 2 weeks: 1-normal saline, 2-ZnO-NPs, 3-PbO, and 4-ZnO-NPs+ PbO. Topical application of PbO to rats increased lead contents in blood and different organs causing remarkable oxidative stress damage, apoptosis, and histopathological alterations in these organs. Moreover, PbO-receiving group showed strong positive caspase-3 protein expression with up-regulation of mRNA levels of BAX and COX-2. Co-treatment of ZnO-NPs with PbO could diminish the toxicologic parameters and the above-mentioned immune marker and gene expression levels. Our data suggest the role of ZnO-NPs cream to reduce the risk of lead dermal exposure via preventing absorption and accumulation of it in the internal organs so that it protects these organs from further damage.

Zinc oxide nanoparticles improve testicular steroidogenesis machinery dysfunction in benzo[α]pyrene-challenged rats

Zinc oxide nanoparticles (ZnO NPs) demonstrate potential positive effects on reproduction. However, their protective role against the reproductive toxicity pollutants has not yet been adequately studied at the molecular level. This study was designed to assess this objective using Benzo[α]pyrene B[a]P as reproductive toxic agent . Forty-eight mature male rats were randomly distributed into six groups: Group1 (negative control); Groups 2 and 3 (positive control I and II, wherein the animals were treated with 10 and 30 mg ZnO NPs/kg BW, respectively); Group 4 (B[a]P group; treated with 150 mg B[a]P/kg BW); and Groups 5 and 6 (subjected to B[a]P treatment co-administered with different concentrations of ZnO NPs). We investigated oxidative stress biomarkers; cholesterol side-chain cleavage enzyme (CYP11A1), steroidogenic acute regulatory protein (StAR), and 3β-hydroxysteroid dehydrogenase (3β-HSD) gene expression; testosterone levels; and histopathology of the liver, kidney, and testicles. The B[a]P-treated group showed significant deterioration in all reproductive parameters and displayed induced oxidative stress. ZnO NPs remarkably reduced oxidative stress, effectively upregulated the mRNA levels of CY11A1, StAR, and 3β-HSD, and improved the histological pictures in the examined organs. At their investigated doses and given their NPs properties, ZnO NPs demonstrated a marked ameliorative effect against the reproductive toxic effects of B[a]P. Further studies are needed to thoroughly investigate the molecular mechanisms of ZnO NPs.

Apoptotic Effect and Anticancer Activity of Biosynthesized Silver Nanoparticles from Marine Algae Chaetomorpha linum Extract Against Human Colon Cancer Cell HCT-116

The green approach of nanoparticle synthesis has gained more attention by researchers because of its nontoxic, eco-friendly, biocompatible, and sustainable nature. The present research investigated the anticancer effectiveness of silver nanoparticles synthesized from marine algae Chaetomorpha linum (C. linum) against colon cancer cell HCT-116 in vitro. Biosynthesized silver nanoparticles (C-AgNPs) are characterized using UV-spectrophotometry, dynamic light scattering (DLS), X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). We demonstrated the dose-dependent cytotoxic effect of C-AgNPs in human colorectal carcinoma cells (HCT-116) using MTT assay. The apoptosis induction in HCT-116 cells caused by C-AgNPs has studied fluorescence microscope by staining with fluorogenic agents 4',6-diamidino-2-phenylindole (DAPI), rhodamine 123, and 2',7'-dichlorodihydrofluorescein diacetate (H₂DCFDA). By using a flow cytometric test, the apoptotic action of C-AgNPs was performed. The immunoblotting study of caspases, as well as pro-apoptotic and anti-apoptotic protein expression, was studied using the PCR technique to understand the underlying molecular mechanism of C-AgNPs on cancer cells. The apoptotic studies showed an increase in the expression of apoptotic caspase 3, caspase 9, BH3-interacting domain death agonist (Bid), and Bax, along with a decrease in the anti-apoptotic protein like Bcl-2 and Bcl-xl, thereby veritably confirmed by immunoblotting and qPCR technique. The biosynthesized C-AgNPs was an efficient anticancer agent that can induce apoptosis in the HCT-116 colon cells.

Comparative assessment of the bactericidal effect of nanoparticles of copper oxide, silver, and chitosan-silver against Escherichia coli infection in broilers

Escherichia coli infection is considered one of the most economically important multi-systemic diseases in poultry farms. Several nanoparticles such as silver, chitosan, and copper oxide are known to be highly toxic to several microbes. However, there are no data concerning their success against in vivo experimental E. coli infection in broilers. Therefore, the present study was designed to investigate the bactericidal effect of low doses of CuO-NPs (5 mg/kg bwt), Ag-NPs (0.5 mg/kg bwt), and Ch-Ag NPs (0.5 mg/kg bwt) against E. coli experimental infection in broilers. One hundred chicks were divided into five groups as follows: (1) control; (2) E. coli (4 × 108 CFU/ml) challenged; (3) E. coli +CuO-NPs; (4) E. coli +Ag-NPs; (5) E. coli +Ch-Ag NPs. The challenged untreated group, not NPs treated groups, recorded the lowest weight gain as well as the highest bacterial count and lesion score in all examined organs. The highest liver content of silver was observed in Ag-NPs treated group compared with the Ch-Ag NPs treated group. Our results concluded that Ch-Ag NPs not only had the best antibacterial effects but also acted as a growth promoter in broilers without leaving any residues in edible organs. We recommend using Ch-Ag NPs in broiler farms instead of antibiotics or probiotics.

The protective effects of Terminalia laxiflora extract on hepato-nephrotoxicity induced by fipronil in male rats

The present study was led to investigate the defensive role of Terminalia laxiflora extract (TLE) on fipronil (FPN) induced hepatotoxicity and nephrotoxicity in male rats. Rats were administered with TLE (100 mg/kg) against the renal toxicity and hepatotoxicity induced by administration of FPN (10.5 mg/kg) for 30 days. At the end of the experimental period, the serum, liver, and kidneys were harvested and assessed for subsequent analysis. FPN administration to rats resulted in a significant elevation of serum transaminases, urea, and creatinine. Also, FPN-treated groups exhibited a marked reduction in total protein and albumin levels. Compared with the control group, the level of malondialdehyde (MDA) was elevated in groups treated with FPN, whereas superoxide dismutase (SOD), catalase (CAT) activities, and glutathione levels were distinctly reduced in this group. Significant increases in genomic DNA fragmentation and the expression level of the caspase-3 gene were also recorded. The biochemical result was supported by histopathological findings. Co-administration of TLE along with FPN significantly diminished the liver and kidney function tests decreased the level of lipid peroxidation, and enhanced all the antioxidant enzymes, while also diminishing the expression of caspase-3 and DNA laddering, indicating amelioration of DNA damage. These results indicate that TLE plays a vital role in diminishing FPN-induced hepatotoxicity and nephrotoxicity.