An Improved Method for Fabrication of Ag-GO Nanocomposite with Controlled Anti-Cancer and Anti-bacterial Behavior; A Comparative Study

Phytochemical profiling and antibacterial activities of Ziziphora tenuior root extracts: a molecular docking against VanA of vancomycin-resistant enterococci

Medicinal plants, renowned for their antibacterial phytocompounds and secondary metabolites, hold significant promise in addressing antibiotic-resistant bacterial strains. This study aimed to conduct phytochemical profiling of the methanolic and dichloromethane extracts of Ziziphora tenuior root using the GC-MS technique. These extracts' antioxidant potential was assessed via DPPH assay and their antibacterial activity was evaluated against S. aureus, E. coli, and VRE bacterial strains. Furthermore, the drug-ligand interactions between the extracts' biocompounds and d-alanyl-d-lactate ligase (VanA) protein of vancomycin-resistant enterococci strains (VRE) were analyzed using molecular docking. Based on the results, 74% of methanolic extract consisted of (3methyl, 24S)-stigmast-5-en-3-ol (which is a β-sitosterol), followed by Tetrasiloxane, decamethyl (15.5%), and 1-methyl-4-phenyl-5-thioxo-1,2,4-triazolidin-3-one (10.5%). Also, the only predominant compound identified in the dichloromethane extract was Benzo[h]quinoline, 2,4-dimethyl-. Both extracts showed antioxidant activity, while the antioxidant activity of the methanolic extract (IC50 = 95.33 μg/ml) was significantly higher than that of the dichloromethane extract (IC50 = 934.23 μg/ml). Also, both extracts displayed substantial antibacterial efficacy against the tested pathogens, particularly against VRE. Moreover, the in silico analysis revealed that (3methyl, 24S)-stigmast-5-en-3-ol and Benzo[h]quinoline,2,4-dimethyl- exhibited notable interactions with VanA through docking energy values of - 9.0 and - 9.1 kcal/mol, respectively. Furthermore, these compounds formed 2 and 1 hydrogen bonds with VanA, respectively, highlighting their potential as effective interactants. These findings provide valuable visions into the therapeutic potentials of these plant-derived biocompounds in combating antibiotic-resistant bacterial infections.

The application of graphene oxide and ferroptosis in the diagnosis and treatment of colorectal cancer: a narrative review

Background and Objective

Colorectal cancer (CRC), a leading global malignancy, continues to challenge the medical community. Despite advancements in surgical, chemotherapeutic, radiation, targeted, and immunotherapeutic strategies, issues like resistance and side effects persist. This review illuminates the potential of ferroptosis, an emerging non-apoptotic cell death form, and graphene oxide (GO), with its distinctive physicochemical properties, in CRC therapy.

Methods

The databases search included PubMed, Medline and Web of Science. Search terms focused on CRC, graphene, GO, ferroptosis, and related aspects in therapy and drug delivery. The time frame for literature retrieval was up to April 2024. Studies in languages other than English were excluded.

Key Content and Findings

Ferroptosis has been recognized for its role in addressing treatment resistance, a notable hurdle in effective CRC management. This form of cell death offers a promising avenue for enhancing the effectiveness of existing treatments. However, understanding its mechanisms and clinical implications in CRC remains an area of active research, with significant progress required for its practical application. Simultaneously, GO, a versatile two-dimensional material, has demonstrated substantial potential in biomedical applications, especially in cancer therapy. Its high specific surface area and unique π-electron domains facilitate the effective binding of chemotherapy drugs, target genes, and photosensitizers. This makes GO a promising candidate in cancer diagnosis and treatment, particularly through tumor photothermal and photodynamic therapy (PDT). Despite these advancements, GO's clinical application faces challenges, including in vitro cytotoxicity and decreased biodegradability, necessitating further research.

Conclusions

This review focuses on the characteristics of GO and ferroptosis, as well as their applications in tumor diagnosis and treatment, with a particular emphasis on their potential in CRC.

Fabrication of Multifunctional Tents Using Canvas Fabric

Herein, this study was compiled to investigate a suitable solution for the fabrication and development of the multifunctional defense tent from previously reported research. The military always needs to protect their soldiers and equipment from detection. The advancement of infrared detection technology emphasizes the significance of infrared camouflage materials, reducing thermal emissions for various applications. Objects emit infrared radiation detectable by devices, making military targets easily identifiable. Infrared camouflage mitigates detection by lowering an object's infrared radiation, achieved by methods such as reducing surface temperature, which is crucial in designing military tents with infrared (IR) camouflage, considering water repellency and antibacterial features. Water repellency, as well as antimicrobial properties, in army tents is also important as they have to survive in different situations. All these problems should be addressed with the required properties; therefore, the authors try to introduce a new method from which multifunctional tents can be produced through economical, multifunctional, and sustainable materials that have IR protection, water repellency, ultraviolet (UV) protection, air filtration and permeability, and antimicrobial properties. There is still no tent that performs multiple functions at a time, even those functions that do not correlate with each other such as water repellency, IR protection, antimicrobial, and air permeability. So, a multifunctional tent could be the solution to all these problems having all the properties discussed above. In this study based on the literature review, authors concluded a method for the required tent for canvas fabric coated with zinc sulfide (ZnS), graphene oxide (GO), and zinc oxide (ZnO), or these materials should be incorporated in fiber formation because fiber composition has more impact. These multifunctional tents will be very beneficial due to their multifunctions like weather resistance, durability, and long life. These would help the army in their missions by concealing their soldiers and equipment from detection by cameras and providing filtered air inside the tent in case of gases or explosions. The proposed method will help to fulfill the stated and implied needs of customers.

Synthesis and characterization of magnetic Ag-Fe3O4@polymer hybrid nanocomposite systems with promising antibacterial application

INTRODUCTION

Bacterial infections caused by different strains of bacteria still one of the most important disorders affecting humans worldwide. Polymers nanocomposite systems could be considered as an alternative to conventional antibiotics to eradicate bacterial infections.

SIGNIFICANCE

In an attempt to enhance the antibacterial performance of silver and iron oxide nanoparticles, decrease their aggregation and toxicity, a polymeric hybrid nanocomposite system combining both nanoparticles is produced.

METHODS

Magnetic Ag-Fe3O4@polymer hybrid nanocomposites prepared using different polymers, namely polyethylene glycol 4000, ethyl cellulose, and chitosan were synthesized via wet impregnation and ball-milling techniques. The produced nanocomposites were tested for their physical properties and antibacterial activities.

RESULTS

XRD, FT-IR, VSM, and TEM results confirmed the successful preparation of hybrid nanocomposites. Hybrid nanocomposites have average crystallite sizes in the following order Ag-Fe3O4@CS (8.9 nm) < Ag-Fe3O4@EC (9.0 nm) < Ag-Fe3O4@PEG4000 (9.4 nm) and active surface area of this trend Ag-Fe3O4@CS (130.4 m2g-1) > Ag-Fe3O4@EC (128.9 m2g-1) > Ag-Fe3O4@PEG4000 (123.4 m2g-1). In addition, they have a saturation magnetization in this order: Ag-Fe3O4@PEG4000 (44.82 emu/g) > Ag-Fe3O4@EC (40.14 emu/g) > Ag-Fe3O4@CS (22.90 emu/g). Hybrid nanocomposites have a pronounced antibacterial action against Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus intermedius compared to iron oxide nanoparticles and positive antibacterial drug. In addition, both Ag-Fe3O4@EC and Ag-Fe3O4@CS have a lower MIC values compared to Ag-Fe3O4@PEG and positive control.

CONCLUSION

Magnetic Ag-Fe3O4 hybrid nanocomposites could be promising antibacterial nanomaterials and could pave the way for the development of new materials with even more unique properties and applications.

Drug-Loaded Silver Nanoparticles-A Tool for Delivery of a Mebeverine Precursor in Inflammatory Bowel Diseases Treatment

Chronic, multifactorial illnesses of the gastrointestinal tract include inflammatory bowel diseases. One of the greatest methods for regulated medicine administration in a particular region of inflammation is the nanoparticle system. Silver nanoparticles (Ag NPs) have been utilized as drug delivery systems in the pharmaceutical industry. The goal of the current study is to synthesize drug-loaded Ag NPs using a previously described 3-methyl-1-phenylbutan-2-amine, as a mebeverine precursor (MP). Methods: A green, galactose-assisted method for the rapid synthesis and stabilization of Ag NPs as a drug-delivery system is presented. Galactose was used as a reducing and capping agent forming a thin layer encasing the nanoparticles. Results: The structure, size distribution, zeta potential, surface charge, and the role of the capping agent of drug-loaded Ag NPs were discussed. The drug release of the MP-loaded Ag NPs was also investigated. The Ag NPs indicated a very good drug release between 80 and 85%. Based on the preliminary results, Ag NPs might be a promising medication delivery system for MP and a useful treatment option for inflammatory bowel disease. Therefore, future research into the potential medical applications of the produced Ag NPs is necessary.

Effectiveness of Nonfunctionalized Graphene Oxide Nanolayers as Nanomedicine against Colon, Cervical, and Breast Cancer Cells

Recent studies in nanomedicine have intensively explored the prospective applications of surface-tailored graphene oxide (GO) as anticancer entity. However, the efficacy of nonfunctionalized graphene oxide nanolayers (GRO-NLs) as an anticancer agent is less explored. In this study, we report the synthesis of GRO-NLs and their in vitro anticancer potential in breast (MCF-7), colon (HT-29), and cervical (HeLa) cancer cells. GRO-NLs-treated HT-29, HeLa, and MCF-7 cells showed cytotoxicity in the MTT and NRU assays via defects in mitochondrial functions and lysosomal activity. HT-29, HeLa, and MCF-7 cells treated with GRO-NLs exhibited substantial elevations in ROS, disturbances of the mitochondrial membrane potential, an influx of Ca2+, and apoptosis. The qPCR quantification showed the upregulation of caspase 3, caspase 9, bax, and SOD1 genes in GRO-NLs-treated cells. Western blotting showed the depletion of P21, P53, and CDC25C proteins in the above cancer cell lines after GRO-NLs treatment, indicating its function as a mutagen to induce mutation in the P53 gene, thereby affecting P53 protein and downstream effectors P21 and CDC25C. In addition, there may be a mechanism other than P53 mutation that controls P53 dysfunction. We conclude that nonfunctionalized GRO-NLs exhibit prospective biomedical application as a putative anticancer entity against colon, cervical, and breast cancers.

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

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

A new theranostic pH-responsive niosome formulation for Doxorubicin delivery and bio-imaging against breast cancer

As one of the newest generations of nanoplatforms, smart nanotheranostics have attracted signifivant attentions for medical applications, especially in oncology and cancer treatment. Indeed, their capability to provide treatment and diagnosis simultaneously leads to reduce time and side effects along with improving the performance. This study aims to introduce a novel smart nano-platform composed of doxorubicin-loaded pH-responsive stealth niosomes containing CdSe/ZnS Quantum dots as an imaging agent. Drug loaded nano-platform was fabricated via thin-film hydration method and then evaluated using different physicochemical tests. The entrapment efficiency and release profile of doxorubicin were assessed at three different pH (4, 6.5, and 7.4). Biological features and imaging ability of the nanoparticles were also evaluated by MTT assay, apoptosis assay, and fluorescence microscopy. Results showed that the fabricated nanoparticles were round-shaped, with a mean size of about 100±10 nm, -2 mV surface charge, and about 87% entrapment efficiency. The drug release profile presented a pH-responsive behavior (80, 60, and 40% drug release in pH 4, 6.5, and 7.4, respectively). The bio-activity assessments showed nearly 55% cytotoxicity effects via inducing cell apoptosis. Besides, the uptake of samples by the cells was confirmed through fluorescence imaging. Based on the results, this new nanoformulation could be considered as a candidate for future cancer theranostic applications.

Graphene oxide quantum dot-chitosan nanotheranostic platform as a pH-responsive carrier for improving curcumin uptake internalization: In vitro & in silico study

We herein fabricated a cancer nanotheranostics platform based on Graphene Oxide Quantum Dot-Chitosan-polyethylene glycol nanoconjugate (GOQD-CS-PEG), which were targeted with MUC-1 aptamer towards breast and colon tumors. The interaction between aptamer and MUC-1 receptor on the desired cells was investigated utilizing molecular docking. The process of curcumin release was investigated, as well as the potential of the produced nanocomposite in targeted drug delivery, specific detection, and photoluminescence imaging. The fluorescence intensity of GOQD-CS-PEG was reduced due to transferred energy between (cytosine-guanin) base pairs in the hairpin structure of the aptamer, resulting in an "on/off" photoluminescence bio-sensing. Interestingly, the integration of pH-responsive chitosan nanoparticles in the nanocomposite results in a smart nanocomposite capable of delivering more curcumin to desired tumor cells. When selectively binds to the MUC-1 receptor, the two strands of aptamer separate in acidic conditions, resulting in a sustained drug release and photoluminescence recovery. The cytotoxicity results also revealed that the nanocomposite was more toxic to MUC-1-overexpressed tumor cells than to negative control cell lines, confirming its selective targeting. As a result, the proposed nanocomposite could be used as an intelligent cancer nanotheranostic platform for tracing MUC-1-overexpressed tumor cells and targeting them with great efficiency and selectivity.

Inhibition performances of graphene oxide/silver nanostructure for the microbial corrosion: molecular dynamic simulation study

Steel is one of the mainly used materials in the oil and gas industry. However, it is susceptible to the marine corrosion, which 20% of the total marine corrosion is caused by microbiologically influenced corrosion (MIC). The economic and environmental impacts of corrosion are significant, and it is crucial to fight against corrosion in a proper sustainability context and environmental-friendly methods. In this study, the graphene oxide/silver nanostructure (GO-Ag) inhibitory effect on the corrosion of steel in the presence of sulfate reducing bacteria (SRB) was investigated, via weight loss (WL) and Tafel polarization measurements. Moreover, molecular dynamic (MD) simulations were performed to obtain a deep understanding of the corrosion inhibition effect of GO-Ag. GO-Ag showed a significant antibacterial effect at 80 ppm. Moreover, WL and Tafel polarization measurements illustrated a great inhibition efficiency, which reached up to 84% reduction of WL and 98% reduction of corrosion current density (I_corr) after 7 days of incubation with GO-Ag. Based on MD simulations, bonding energy reached to the larger value in the presence of GO-Ag, which indicated the ability of graphene oxide nanosheets to be adsorbed on the steel surface and prevent the access of corrosive agents to the steel surface. The radial distribution function (RDF) results implied distance between corrosive agent (water and SRB) and steel surface (Fe atoms), which indicated protection of the steel surface due to the effective adsorption of GO nanosheets through the active sites of the steel surface. The mean square displacement (MSD) result showed smaller displacement of the corrosive particles on the surface of steel, resulting that the GO-Ag molecules bonded with Fe molecules on the surface of steel.

Properties Evolution of Some Hydraulic Mortars Incorporating Graphene Oxides

In this experimental study, the mechanical and adhesion properties of several hydraulic lime mortars incorporating graphene oxide (GO)-based nanomaterials were evaluated. Four different composite mortar samples were prepared by adding different percentages of GO-based powders (functionalized), i.e., 1 wt.% GO, 5 wt.% GO, 5wt.% GO-Ag-GO-Fly ash, and 5 wt.% GO-ZnO-GO-TiO2 into the reference mortar sample. The mortar specimens were analyzed through mechanical tests, FT-IR, and SEM. The behavior of selected mortars exposed to chemical attacks was also investigated. The results indicate that the addition of the functionalized GO-based powders leads to a significant improvement in the mortar’s adhesion to the brick substrate (up to 80%) compared to the reference sample, especially in the case of the hydraulic lime mortar incorporating the mixture of GO-Ag and GO-Fly ash, which also showed good resistance to chemical attacks.

Antineoplastic activity of biogenic silver and gold nanoparticles to combat leukemia: Beginning a new era in cancer theragnostic

The American Cancer Society estimated around 61,090 new cases of leukemia were diagnosed, and around 23,660 people died from this disease in the United States alone in 2021. Due to its burden on society, there is an unmet need to explore innovative approaches to overcome leukemia. Among different strategies that have been explored, nanotechnology appears to be a promising and effective approach for therapeutics. Specifically, biogenic silver and gold nanoparticles (NPs) have attracted significant attention for their antineoplastic activity toward leukemia cancer cells due to their unique physicochemical properties. Indeed, these nanostructures have emerged as useful approaches in anti-leukemic applications, either as carriers to enhance drug bioavailability and its targeted delivery to a specific organ or as a novel therapeutic agent. This review explores recent advances in green synthesized nanomaterials and their potential use against leukemia, especially focusing on silver (Ag) and gold (Au) nanostructures. In detail, we have reviewed various eco-friendly methods of bio-synthesized NPs, their analytical properties, and toxicity effects against leukemic models. This overview confirms the satisfactory potency of biogenic NPs toward leukemic cells and desirable safety profiles against human native cells, which opens a promising door toward commercializing these types of nontherapeutic agents if challenges involve clinical validations, reproducibility, and scalability could be resolved.

Graphene and graphene oxide with anticancer applications: Challenges and future perspectives

Graphene-based materials have shown immense pertinence for sensing/imaging, gene/drug delivery, cancer therapy/diagnosis, and tissue engineering/regenerative medicine. Indeed, the large surface area, ease of functionalization, high drug loading capacity, and reactive oxygen species induction potentials have rendered graphene- (G-) and graphene oxide (GO)-based (nano)structures promising candidates for cancer therapy applications. Various techniques namely liquid-phase exfoliation, Hummer's method, chemical vapor deposition, chemically reduced GO, mechanical cleavage of graphite, arc discharge of graphite, and thermal fusion have been deployed for the production of G-based materials. Additionally, important criteria such as biocompatibility, bio-toxicity, dispersibility, immunological compatibility, and inflammatory reactions of G-based structures need to be systematically assessed for additional clinical and biomedical appliances. Furthermore, surface properties (e.g., lateral dimension, charge, corona influence, surface structure, and oxygen content), concentration, detection strategies, and cell types are vital for anticancer activities of these structures. Notably, the efficient accumulation of anticancer drugs in tumor targets/tissues, controlled cellular uptake properties, tumor-targeted drug release behavior, and selective toxicity toward the cells are crucial criteria that need to be met for developing future anticancer G-based nanosystems. Herein, important challenges and future perspectives of cancer therapy using G- and GO-based nanosystems have been highlighted, and the recent advancements are deliberated.

Synthesis and Characterization of Some Graphene Oxide Powders Used as Additives in Hydraulic Mortars

Various powders of graphene oxide (GO), GO with silver (GO-Ag) and zinc oxide (GO-ZnO) were obtained. The powders were silanized with (3-aminopropyl) triethoxysilane (APTES) aiming to be used, in a future stage, as additives in the hydraulic lime mortars composition. The powders were characterized by Fourier Transform Infrared Spectrometry (FTIR) and Scanning Electron Microscopy (SEM) before and after the silanization process. GO, GO-Ag, GO-Ag-APTES, GO-ZnO and GO-ZnO-APTES powders were also investigated by Thermogravimetric Analysis (TG/DTA) and Ultraviolet–Visible Spectroscopy (UV-Vis). Likewise, the antibacterial effect of powders against five bacterial strains was evaluated. The peaks associated to the functional groups from GO, GO-APTES, GO-Ag, GO-Ag-APTES, GO-ZnO and GO-ZnO-APTES powders were identified by FTIR analysis. The mass losses of powders, analyzed by TG/DTA were lower than those recorded for GO. By UV-VIS analysis, maxima corresponding to the electronic π-π * and n-π * transitions were recorded. SEM images highlighted the lamellar and layered structure of GO, but also the presence of Ag and Zn nanoparticles on the surface of graphene sheets. All these results confirm the presence of Ag/ZnO/APTES on the GO. The antibacterial effect evaluated by recording the diameter of the inhibition zone ranged between 12–22 mm.

Room-Temperature One-Step Synthesis of Silver/Reduced Graphene Oxide Nanocomposites as an Excellent Microwave Absorber

The present study is focused on room-temperature synthesis carried out by reduction of an aqueous silver nitrate (AgNO₃) and AgNO₃/graphene oxide (GO) dispersion using a low-cost commercial Fehling B solution in one step to form silver quantum dots (Ag QDs) and their Ag/reduced graphene oxide (Ag/RGO) nanocomposites and their characterization. The crystallinity, surface chemistry, structural, and morphological studies indicated the formation of crystalline small-sized quasispherical-functionalized Ag particles distributed uniformly on the surface of RGO. The conductivity measurements further showed an improvement in the conductivity of Ag/RGO nanocomposites as compared to neat Ag QDs. Our findings showed that Ag/RGO nanocomposites prepared by using 0.055 wt % of GO exhibited a total enhanced electromagnetic interference (EMI)-shielding efficiency (SE_T) of ∼39.2-42.3 dB (2-8 GHz) with a maximum value of ∼43.8 dB at 7. 5 GHz due to conduction loss, an interconnected conducting network, and a synergistic effect, and it followed an absorption mechanism. Furthermore, this superior absorption-dominated shielding conferred reflection loss (R_L) in the range of -79 to -82.5 dB with a R_L minima of -88 dB at 7.5 GHz, considering an effective absorption bandwidth of ∼6 GHz with 99.9% absorptivity. It is anticipated that Ag/RGO nanocomposites prepared in one step at room temperature could find potential EMI-shielding applications.

Biosynthesis of reduced graphene oxide using Turbinaria ornata and its cytotoxic effect on MCF-7 cells

Graphene‐based nanomaterials are gaining importance in biomedicine because of their large surface areas, solubility, and biocompatibility. Green synthesis is the most economical method for application, as it is rapid and sustainable. Biofunctionalized reduced graphene oxide (TrGO) nanosheets were synthesized using methanol extract of Turbinaria ornata, and bioreduction of graphene oxide was primarily confirmed and characterized using UV‐visible, Fourier transform infrared (FTIR), and X‐ray diffraction spectroscopy and further characterized by zeta potential and transmission electron microscopy. The FTIR spectra of TrGO showed a decrease in the band intensities of oxygen groups, thus confirming effective deoxygenation. The zeta potential value of −34.6 mV revealed that synthesized TrGO was highly stable. The cytotoxic effect of TrGO against MCF‐10A and MCF‐7 cells was ascertained using MTT assay, showed a greater cytotoxic effect on MCF‐7 cells. The IC₅₀ of TrGO treatment against MCF‐7 was calculated to be 31.25 µg, which is onefold lower than the cytotoxic effect of methanolic extract of T. ornata (60.0 ± 1.14 µg/ml). In addition, there was a statistically significant difference in cell viability between MCF‐10A and MCF‐7 cells in the treatment of TrGO. Hence, this study results in an efficient green reductant for producing rGO nanosheets that possess cytotoxicity against breast cancer cells.

Current approaches for the exploration of antimicrobial activities of nanoparticles

Infectious diseases of bacterial and viral origins contribute to substantial mortality worldwide. Collaborative efforts have been underway between academia and the industry to develop technologies for a more effective treatment for such diseases. Due to their utility in various industrial applications, nanoparticles (NPs) offer promising potential as antimicrobial agents against bacterial and viral infections. NPs have been established to possess potent antimicrobial activities against various types of pathogens due to their unique characteristics and cell-damaging ability through several mechanisms. The recently accepted antimicrobial mechanisms possessed by NPs include metal ion release, oxidative stress induction, and non-oxidative mechanisms. Another merit of NPs lies in the low likelihood of the development of microbial tolerance towards NPs, given the multiple simultaneous mechanisms of action against the pathogens targeting numerous gene mutations in these pathogens. Moreover, NPs provide a fascinating opportunity to curb microbial growth before infections: this outstanding feature has led to their utilization as active antimicrobial agents in different industrial applications, e.g. the coating of medical devices, incorporation in food packaging, promoting wound healing and encapsulation with other potential materials for wastewater treatment. This review discusses the progress and achievements in the antimicrobial applications of NPs, factors contributing to their actions, mechanisms underlying their efficiency, and risks of their applications, including the antimicrobial action of metal nanoclusters (NCs). The review concludes with a discussion of the restrictions on present studies and future prospects of nanotechnology-based NPs development.

A Novel Green Preparation of Ag/RGO Nanocomposites with Highly Effective Anticancer Performance

The efficacy of current cancer therapies is limited due to several factors, including drug resistance and non-specific toxic effects. Due to their tuneable properties, silver nanoparticles (Ag NPs) and graphene derivative-based nanomaterials are now providing new hope to treat cancer with minimum side effects. Here, we report a simple, inexpensive, and eco-friendly protocol for the preparation of silver-reduced graphene oxide nanocomposites (Ag/RGO NCs) using orange peel extract. This work was planned to curtail the use of toxic chemicals, and improve the anticancer performance and cytocompatibility of Ag/RGO NCs. Aqueous extract of orange peels is abundant in phytochemicals that act as reducing and stabilizing agents for the green synthesis of Ag NPs and Ag/RGO NCs from silver nitrate and graphene oxide (GO). Moreover, the flavonoid present in orange peel is a potent anticancer agent. Green-prepared Ag NPs and Ag/RGO NCs were characterized by UV-visible spectrophotometry, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and dynamic light scattering (DLS). The results of the anticancer study demonstrated that the killing potential of Ag/RGO NCs against human breast cancer (MCF7) and lung cancer (A549) cells was two-fold that of pure Ag NPs. Moreover, the cytocompatibility of Ag/RGO NCs in human normal breast epithelial (MCF10A) cells and normal lung fibroblasts (IMR90) was higher than that of pure Ag NPs. This mechanistic study indicated that Ag/RGO NCs induce toxicity in cancer cells through pro-oxidant reactive oxygen species generation and antioxidant glutathione depletion and provided a novel green synthesis of Ag/RGO NCs with highly effective anticancer performance and better cytocompatibility.

Down-regulation of biofilm-associated genes in mecA-positive methicillin-resistant S. aureus treated with M. communis extract and its antibacterial activity

Considering the prevalence of resistance to antibiotics, the discovery of effective agents against resistant pathogens is of extreme urgency. Herein, 26 mecA-positive methicillin-resistant S. aureus (MRSA) isolated from clinical samples were identified, and their resistance to 11 antibiotics was investigated. Next, the antibacterial and anti-biofilm activity of the ethanolic extract of M. communis on these strains was evaluated. Furthermore, the effect of this extract on the expression of biofilm-associated genes, icaA, icaD, bap, sarA, and agr, was studied. According to the results, all isolated strains were multidrug-resistant and showed resistance to oxacillin and tetracycline. Also, 96.15 and 88.46 % of them were resistant to gentamicin and erythromycin. However, the extract could effectively combat the strains. The minimum inhibitory concentration (MIC) against different strains ranged from 1.56 to 25 mg/ml and the minimum bactericidal concentration (MBC) was between 3.125 and 50 mg/ml. Even though most MRSA (67 %) strongly produced biofilm, the sub-MIC concentration of the extract destroyed the pre-formed biofilm and affected the bacterial cells inside the biofilm. It could also inhibit biofilm development by significantly decreasing the expression of icaA, icaD, sarA and bap genes involved in biofilm formation and development. In conclusion, the extract inhibits biofilm formation, ruins pre-formed biofilm, and kills cells living inside the biofilm. Furthermore, it down-regulates the expression of necessary genes and nips the biofilm formation in the bud.

Facile multifunctional-mode of fabricated biocompatible human serum albumin/reduced graphene oxide/Cladophora glomeratananoparticles for bacteriostatic phototherapy, bacterial tracking and antioxidant potential

To overcome multi-drug resistance in microbes, highly efficient antimicrobial substances are required that have a controllable antibacterial effect and are biocompatible. In the present study, an efficient phototherapeutic antibacterial agent, human serum albumin (HSA)/reduced graphene oxide (rGO)/Cladophora glomeratabionanocomposite was synthesized by the incorporation of rGO nanoparticles with HSA, forming protein-rGO, and decorated with a natural freshwater seaweedCladophora glomerata. The prepared HSA/rGO/Cladophora glomeratabionanocomposite was characterized by spectroscopic (UV-vis, FTIR, XRD and Raman) and microscopic (TEM and SEM) techniques. The as-synthesized bionanocomposite showed that sunlight/NIR irradiation stimulated ROS-generating dual-phototherapic effects against antibiotic-resistant bacteria. The bionanocomposite exerted strong antibacterial effects (above 96 %) against amoxicillin-resistantP. aeruginosaandS. aureus, in contrast to single-model-phototherapy. The bionanocomposite not only generated abundant ROS for killing bacteria, but also expressed a fluorescence image for bacterial tracking under sunlight/NIR irradiation. Additionally, the bionanocomposite displayed pronounced antioxidant activity.

Probiotic potential and anticancer properties of Pediococcus sp. isolated from traditional dairy products

Herein, 18 lactic acid bacteria isolated from 30 samples of traditional dairy products were identified, and their probiotic potential was evaluated. According to the results, almost all strains showed the probiotic properties sufficiently, though M1 had better characterise. 16S rRNA gene sequencing revealed that this strain belongs to the Pediococcus sp. (<95 % similarity). This strain had substantial antipathogenic activity and did not show any worrying antibiotic resistance. Also, the strain was resistant to high concentrations of bile salt (1 %), NaCl (6.5 %), and low pH (2). Furthermore, it was revealed that cell-free supernatant (CFS), heat-killed cells and live cells derived from M1 significantly decreased the viability of MCF-7 cells so that the CFS resulted in 85 % cell death. Flow cytometry and western blot analysis determined that this compound induced apoptosis in the cancerous cells through increasing the BAX protein expression and decreasing the Bcl-2 protein expression.

Carbon-based nanomaterials for targeted cancer nanotherapy: recent trends and future prospects

Carbon-based nanomaterials are becoming attractive materials due to their unique structural dimensions and promising mechanical, electrical, thermal, optical and chemical characteristics. Carbon nanotubes, graphene, graphene oxide, carbon and graphene quantum dots have numerous applications in diverse areas, including biosensing, drug/gene delivery, tissue engineering, imaging, regenerative medicine, diagnosis, and cancer therapy. Cancer remains one of the major health problems all over the world, and several therapeutic approaches are focussed on designing targeted anticancer drug delivery nanosystems by applying benign and less hazardous resources with high biocompatibility, ease of functionalization, remarkable targeted therapy issues, and low adverse effects. This review highlights the recent development on these carbon based-nanomaterials in the field of targeted cancer therapy and discusses their possible and promising diagnostic and therapeutic applications for the treatment of cancers.

A rapid green synthesis of Ag/AgCl-NC photocatalyst for environmental applications

The present study focuses on extract-mediated Ag nanoparticles (NPs), AgCl-NPs, and Ag/AgCl nanocomposites (NCs) as photocatalysts along with its antimicrobial and dye degradation activities. The synthesis of these NPs and NCs was performed by using Azadirachta indica plant fruit extract and analyzed using UV-Vis spectroscopy to confirm the synthesis and band gap of these NPs and NCs, X-ray diffraction (XRD) to determine its size and crystalline nature. Fourier transform infrared spectroscopy (FTIR) to discern phytochemicals, responsible for the reduction and capping of the synthesized NCs. Scanning electron microscopy analysis (SEM), transmission electron microscopy analysis (TEM), and energy dispersive X-ray (EDX) spectroscopy analysis were performed to validate the morphology and presence of silver and chloride percentage in the composites. Later, these NPs and NCs were used for their potential role in photocatalytic degradation of methylene blue dye and antibacterial activity against Escherichia coli and Staphylococcus aureus of human pathogen. The prepared Ag/AgCl-NCs exhibited an enhanced photocatalytic and antibacterial activities in comparison with pure Ag and AgCl nanomaterials. However, green-synthesized NPs and NCs played dual roles as a photocatalyst and antibacterial agent in various biomedical and industrial sectors. Moreover, we found that it might be a hot research in many other environmental applications in upcoming days.

Photocatalytic activity and antibacterial properties of linen fabric using reduced graphene oxide/silver nanocomposite

Silver nanoparticles were in situ prepared on the surface of linen fabric coated by graphene oxide (GO). In the meantime, the reduction of silver nitrate on the GO-coated fabric led to the synthesis of reduced graphene oxide on the fabric. Two kinds of substrate (cotton and linen) were used. Both RGO/Ag and Ag/GO nanocomposites were added on cotton and linen fabrics through a conventional "pad-dry-cure" method. The chemistry and morphology of the coated surfaces were extensively characterized using Fourier-transformed infrared spectroscopy, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. Resistivity measurements were used for assessing the conductivity. The UV protection properties and the photocatalytic activity of the coated fabrics against methylene blue dye were also investigated. The antibacterial activity was studied against Gram-positive S. aureus and B. subtilis and Gram-negative bacterial strains E. coli and P. aeruginosa by determining the zone of inhibition using the agar diffusion method. Methicillin-resistant Staphylococcus aureus (MRSA) has been responsible for many serious hospital infections worldwide. The fabrics showed superior antibacterial activity and successfully hindered the growth of pathogenic bacterial strains. This outcome suggested that both the RGO/Ag and Ag/GO nanocomposites-coated fabrics could be potentially applied in biomaterials and biomedical fields.

Cubic nano-silver-decorated manganese dioxide micromotors: enhanced propulsion and antibacterial performance

The increasing threat of antibiotic-resistant bacterial strains represents the current antibacterial dilemma and requires novel bactericidal treatment to circumvent this problem. In this work, an efficient strategy for killing bacteria using PEDOT/MnO₂@Ag micromotors is reported based on the intense motion-induced convection and excellent sterilization ability of silver (Ag) ions. A distinctive inner surface structure with cubic Ag nanoparticle growth and dispersion in the MnO₂ layer was constructed by simple cathodic co-electrodeposition. Due to the synergistic catalytic reaction of both MnO₂ and Ag, the micromotors can rapidly swim in very low concentrations of hydrogen peroxide (H₂O₂). The antibacterial efficiency of the micromotors was evaluated with the Escherichia coli (E. coli) model. The continuous movement of micromotors, corresponding to violent mass transfer, along with the on-the-fly release of silver ions, greatly enhanced bacteria killing efficacy, with about 14% increase in bacterial death in 0.2% H₂O₂ solution as compared to no motors. Such proposed micromotors could be ideal candidates for combating antibiotic-resistant bacteria in the fields of biomedical and environmental applications.

Preparation, characterization and anti-cancer activity of graphene oxide-‑silver nanocomposite

This work reported the preparation, characterization, cytotoxicity of green synthesized Lespedeza cuneate mediated silver nanoparticles (Lc-AgNPs) and graphene oxide‑silver nanocomposite (GO-AgNComp) using Lc-AgNPs. The UV absorption spectrum at 419 nm indicated the successful formation of GO-AgNComp. The TEM analysis displayed the thin sheet of graphene decorated Lc-AgNPs in GO-AgNComp. Zeta potential was -13.2 mV for Lc-AgNPs and -30.5 mV for GO-AgNComp. The photothermal conversion efficiency was calculated as 31.09% for GO-AgNComp. The negatively charged zeta potential of GO-AgNComp enhanced its cellular penetration through enhanced permeability and retention (EPR) effect. The near-infrared laser (NIR) induced the anticancer activity of Lc-AgNPs and GO-AgNComp in human lung cancer cells (A549) and brain tumour (LN229). The results indicated that about 50% of A549 cells and LN229 cells were ablated by treatment of 24.73 ± 2.98 μg/mL and 27.34 ± 1.62 μg/mL of Lc-AgNPs, as well by 15.46 ± 2.31 μg/mL and 20.95 ± 1.35 μg/mL of GO-AgNComp respectively. Moreover, GO-AgNComp was not cytotoxic to normal mouse fibroblast cells (NIH3T3), but it caused the cancer cell death in A549 and LN229 through ROS generation, nuclear damage, and mitochondrial membrane potential (∆ψm) loss. This work reported the anticancer potential of GO-AgNComp, which deserves further study on the molecular elucidation of GO-AgNComp mediated human lung and tumour therapy.

Electrochemical Sodium Ion Sensor Based on Silver Nanoparticles/Graphene Oxide Nanocomposite for Food Application

High sodium ion (Na+) consumption leads to high blood pressure which causes many health issues. Real-time determination of Na+ content in food is still important to limit Na+ intake and control the taste of food. In this work, we have developed an electrochemical sensor based on agglomeration of silver nanoparticles (AgNPs) and graphene oxide (GO) modified on a screen-printed silver electrode (SPE) for Na+ detection at room temperature by using cyclic voltammetry (CV). The AgNPs were synthesized through a simple green route using Pistia stratiotes extract as a reducing agent under blue light illumination and mixed with the GO to be a Na+ selective sensing nanocomposite. The AgNPs/GO/SPE sensor showed high sensitivity (0.269 mA/mM/cm2), high selectivity, linear relationship (0–100 mM), good stability, and excellent reproducibility to Na+ detection as well as low limit of detection (9.344 mM) for food application. The interfering species such as K+, Zn2+, Na+, Mg2+, glucose, and ascorbic acid did not have any influence on the Na+ determination. The AgNPs/GO/SPE sensor was successfully applied to determine Na+ in real samples such as fish sauce and seasoning powder of instant noodle.

Green synthesis of silver nanoparticles at low temperature in a fast pace with unique DPPH radical scavenging and selective cytotoxicity against MCF-7 and BT-20 tumor cell lines

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Black peel pomegranate is a rare cultivar of pomegranate distinguished by a deep red color.

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The peel extract of the pomegranate shows unique pharmaceutical properties such as antioxidant and antibacterial.

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This extract synthesis silver nanoparticles in an ultra-fast pace without any heating or additional accelerators.

"Black Peel Pomegranate" is a rare pomegranate cultivar that its specific features are still uncovered particularly in the bio-nano researches. The present study was organized to evaluate this pomegranate's potential in the biosynthesis of silver nanoparticles as well as bio-medical activities. According to the results, the pomegranate peel extract incredibly inhibited 100 % of DPPH free radicals (EC₅₀ = 5 μg/mL). This extract also induced more than 70 % cell death in the treated breast tumor cell lines, BT-20 and MCF-7. Interestingly, the extract was capable of biosynthesis very stable and small (15.6 nm) silver nanoparticles at ambient temperature in an ultra-fast pace. Likewise, these nanoparticles inhibited 77 % of DPPH free radicals (EC₅₀ = 9 μg/mL). Although this antioxidant capacity was lower than that of the extract, instead, the anticancer activity of the synthesized nanoparticles was significantly enhanced, so that they led to more than 81 % and 89 % cell death in the breast tumor cell lines BT-20 and MCF-7, respectively. Considerably, neither the extract nor the biosynthesized silver nanoparticles, showed significant toxicity against non-tumor cell lines (L-929) at the same concentrations. These features of the biosynthesized nanoparticles were quite outstanding in comparison with chemical/commercial ones. Overall, the present study introduces black peel pomegranate as a worthy bio-agent in the biosynthesis of silver nanoparticles with unique activities as well as a cancer treatment.

Antibacterial Activities of Aliphatic Polyester Nanocomposites with Silver Nanoparticles and/or Graphene Oxide Sheets

Aliphatic polyesters such as poly(lactic acid) (PLA), polycaprolactone (PCL) and poly(lactic-co-glycolic) acid (PLGA) copolymers have been widely used as biomaterials for tissue engineering applications including: bone fixation devices, bone scaffolds, and wound dressings in orthopedics. However, biodegradable aliphatic polyesters are prone to bacterial infections due to the lack of antibacterial moieties in their macromolecular chains. In this respect, silver nanoparticles (AgNPs), graphene oxide (GO) sheets and AgNPs-GO hybrids can be used as reinforcing nanofillers for aliphatic polyesters in forming antimicrobial nanocomposites. However, polymeric matrix materials immobilize nanofillers to a large extent so that they cannot penetrate bacterial membrane into cytoplasm as in the case of colloidal nanoparticles or nanosheets. Accordingly, loaded GO sheets of aliphatic polyester nanocomposites have lost their antibacterial functions such as nanoknife cutting, blanket wrapping and membrane phospholipid extraction. In contrast, AgNPs fillers of polyester nanocomposites can release silver ions for destroying bacterial cells. Thus, AgNPs fillers are more effective than loaded GO sheets of polyester nanocomposiites in inhibiting bacterial infections. Aliphatic polyester nanocomposites with AgNPs and AgNPs-GO fillers are effective to kill multi-drug resistant bacteria that cause medical device-related infections.