Ultrafine Silver Nanoparticles Research Articles

A HOF-101@AgNPs-based dual-signal mode aptasensor for electrochemiluminescence and fluorescence detection of E. coli O157:H7

Escherichia coli O157:H7 (E. coli O157:H7) emerges as a foodborne pathogen, emphasizing the imperative for creating precise detection tools. An ultrasensitive electrochemiluminescence/fluorescence (ECL/FL) dual-signal mode aptasensor was constructed for the detection of E. coli O157:H7. Ultrafine silver nanoparticles were loaded on the surface of hydrogen-bonded organic skeleton materials by in-situ photoreduction method, and then combined with aptamers that can identify specific targets to prepare HOF-101@AgNPs@Apt, greatly simplifying the ECL/FL dual-signal mode probe fabrication process and improving sensing reliability. HOF-101@AgNPs@Apt had both strong ECL luminescence and fluorescence, resulting in a high detection sensitivity. The low limit of detection (LOD) for ECL and FL were 0.48 CFU mL−1 and 2.39 CFU mL−1, respectively. Moreover, the proposed dual-signal mode aptasensor has been successfully applied to determine E. coli O157:H7 levels in tap water and milk with superior accuracy and high antiinterference capability, providing a promising method for food safety monitoring.

Dialdehyde cellulose nanofibrils/polyquaternium stabilized ultra-fine silver nanoparticles for synergistic antibacterial therapy

Dialdehyde cellulose nanofibrils (DACNF) and Polyquaternium-10 (PQ: chloro-2-hydroxy-3-(trimethylamino) propyl polyethylene glycol cellulose) have become increasingly favored as antibacterial substances due to their advantageous characteristics. DACNF exhibits exceptional mechanical properties and biocompatibility, whereas PQ demonstrates a positive charge that enhances its antibacterial activity. Combined in a DACNF/PQ mixture, they provide an excellent template material for preparing and stabilizing ultra-fine (~ 10.3 nm) silver nanoparticles (AgNPs) at room temperature. Here, the dialdehyde group of DACNF functions as a reducing agent, while the quaternary ammonium of PQ and carboxylate groups of DACNF synergistically helped in-situ generation of AgNPs uniformly. The synthesized nanocomposites, namely PQ@AgNPs, AgNPs@DACNF, and AgNPs@DACNF/PQ, were subjected to comprehensive characterization using various advanced analytical techniques. The films containing AgNPs@DACNF and AgNPs@DACNF/PQ, fabricated via vacuum filtration, exhibited excellent mechanical properties of 9.78 ± 0.21 MPa, and demonstrated superior antibacterial activity against both Escherichia coli and Staphylococcus aureus. Additionally, the silver ion leaching from the prepared composite films was well controlled. The fabricated nanocomposites also effectively inhibited bacterial biofilm formation. It was also found to be highly biocompatible and non-toxic to human skin fibroblast cells. Furthermore, the nanocomposites exhibited enhanced migration of human dermal fibroblasts, suggesting their potential in facilitating wound healing processes.

Microwave-assisted ultrafine silver nanoparticle synthesis using Mitragyna speciosa for antimalarial applications

Abstract This study investigates the antiplasmodial activity of ultrafine silver nanoparticles (AgNPs, 2–5 nm) synthesized using a green approach involving the Mitragyna speciosa extract and emphasizing the microwave-assisted irradiation technique. Various synthesis parameters were optimized, resulting in the successful production of spherical AgNPs, which exhibited a characteristic surface plasmon resonance peak at around 440 nm. The synthesized AgNPs demonstrated high stability, indicated by a zeta potential value of −28 mV. The antimalarial efficacy of the microwave-assisted AgNPs against the P. falciparum strain was evaluated, demonstrating a half-maximum inhibitory concentration (IC50) value of 1.56 µg·mL−1. Further enhancement in the antimalarial performance was observed when the AgNPs were conjugated with chloroquine (CQ), a traditional antimalarial drug, achieving an impressive IC50 value of 24 ng·mL−1. Additionally, all formulations exhibited low toxicity, with a cytotoxic concentration (CC50) exceeding 800 µg·mL−1 in Vero cells. Complementing these experimental findings, specific computational studies offered insights into the interactions between silver atoms and bioactive compounds in M. speciosa, as well as shedding light on the dynamics of CQ functionalization. These experimental and computational findings emphasize the potential of a sustainable, low-toxicity, and cost-effective AgNP synthesis process, showcasing significant promise in advancing green nanotechnology for the development of effective antimalarial medications.

Gamma irradiation-assisted synthesis of ultrafine AgNPs incorporated in MIL-100(Fe) for efficient catalytic reduction of dye

In this study, we report on the synthesis and characterization of ultrafine silver nanoparticles (AgNPs) incorporated in MIL-100(Fe) metal-organic frameworks (Ag@MIL-100(Fe)) for the efficient catalytic reduction of dyes in water treatment applications. The Ag@MIL-100(Fe)were synthesized using a one-step and effective technique and characterized using various techniques, including X-ray diffraction, transmission electron microscopy, and ultraviolet visible spectroscopy. The results showed that the AgNPs were highly stable and had an average size of ∼3 nm, with excellent distribution within the MIL-100(Fe) framework. The catalytic performance of the hybrid materials was evaluated using the reduction of methyl orange dye as a model reaction, and the results showed that the Ag@MIL-100(Fe) had a high catalytic activity. The enhanced catalytic activity of the nanoparticles is attributed to the synergistic effect between the AgNPs and the MIL-100(Fe) framework, which provides a highly stable and porous matrix for the efficient reduction of dyes. The results of this study demonstrate the potential of Ag@MIL-100(Fe) as a promising material for water treatment and environmental remediation applications.

Oropharyngeal aspirated Ag/TiO2 nanohybrids: Transformation, distribution and toxicity

The wide application of Ag-loaded TiO2 nanohybrids photocatalysts on environment and energy increases the lung exposure risk to humans. Ag/TiO2 nanohybrids inhalation can cause pulmonary toxicity, and there are concerns about whether the loaded silver can be released and cause toxic effects on extrapulmonary organs. Therefore, in this study, the possible biotransformation, biodistribution, and toxicity of oropharyngeal aspirated Ag/TiO2 nanohybrids were investigated first time in vitro and in vivo to answer this question. Firstly, the results of biotransformation showed that the ultrafine silver nanoparticles (~3.5 nm, 2 w/w%) loaded on the surface of nano-TiO2 (~25 nm) could agglomerate and release in Gamble's solution, and the hydrodynamic diameter of the nanohybrids agglomerates increased from about 200 nm to 1 μm. Furthermore, after exposure 10 mg/kg Ag/TiO2 nanohybrids to C57BL/6 J male mice by oropharyngeal aspiration weekly, the biodistribution results showed that the released silver could result in blood, liver, and brain distribution within 28 d. Finally, body weight, organ coefficient, blood biochemical indicators of liver and kidney function, and pathological images demonstrated that although silver could release and lead to extrapulmonary organ distribution, it did not cause obvious extrapulmonary organ damage. The original lung was still the main toxicity and accumulation target organ of Ag/TiO2 nanohybrids, which mainly manifested as the pro-inflammatory and pro-fibrotic effects that should be focused on in the future. Therefore, this study is of great significance in evaluating the safety of Ag-loaded TiO2 nanoparticles and predicting their toxic mechanisms.

Toward a Green Chemistry Approach for the Functionalization of Melamine Foams with Silver Nanoparticles

AbstractThe growing popularity of silver nanoparticles in the field of nanotechnology has created the necessity of developing new sustainable synthesis methods. This study presents a new green in situ functionalization method of melamine foams with silver nanoparticles. The synthesis pathway and the influence of the processing parameters are optimized to phase out 100% of polluting and dangerous solvents while maximizing silver transfer. A deep study of the morphological and chemical changes of the synthesized silver nanoparticles successfully demonstrated that water can be used as the only solvent for obtaining active melamine foams with potential application in multiple fields. Results showed that rising reaction temperatures from environmental to mild conditions (40 °C and 60 °C) is crucial for obtaining high functionalization yields with this green method. Following the optimum fabrication conditions using only water, highly functionalized melamine foams showed a great amount of ultrafine silver nanoparticles distributed over the porous structure.

Near-Infrared Light-Mediated Cyclodextrin Metal-Organic Frameworks for Synergistic Antibacterial and Anti-Biofilm Therapies.

Bacterial infections pose a significant threat to global public health; therefore, the development of novel therapeutics is urgently needed. Herein, a controllable antibacterial nanoplatform utilizing cyclodextrin metal-organic frameworks (CD-MOFs) as a template to synthesize ultrafine silver nanoparticles (Ag NPs) in their porous structure is constructed. Subsequently, polydopamine (PDA) is encapsulated on the CD-MOFs' surface via dopamine polymerization to enhance the water stability and enable hyperthermia capacity. The resulting Ag@MOF@PDA generates localized hyperthermia and gradually releases Ag+ to achieve long-term photothermal-chemical bactericidal capability. The release rate of Ag+ can be accelerated by NIR-mediated heating in a controllable manner, quickly reaching the effective concentration and reducing the frequency of medication to avoid potential toxicity. In vitro experiments demonstrate that the combined antibacterial strategy can not only effectively kill both gram-negative and gram-positive bacteria, but also directly eradicate mature biofilms. In vivo results confirm that both bacterial- and biofilm-infected wounds treated with a combination of Ag@MOF@PDA and laser exhibit satisfactory recovery with minimal toxicity, displaying a superior therapeutic effect compared to other groups. Together, the results warrant that the Ag@MOF@PDA realizes synergistic antibacterial capacity and controllable release of Ag+ to combat bacterial and biofilm infections, providing a potential antibiotic-free alternative in the "post-antibiotic era."

Sustainable γ-cyclodextrin frameworks containing ultra-fine silver nanoparticles with enhanced antimicrobial efficacy

Cyclodextrin metal-organic frameworks (CD-MOF) are a class of biocompatible MOF with a great potential in drug delivery applications. Original CD-MOF crystals are fragile and large (0.2–1 mm), which are less useful in pharmaceutical applications. Cetyltrimethylammonium bromide and long chain poly(ethylene) glycol, used in size modulation to produce nanosized CD-MOF can compromise the biocompatibility, and physiochemical properties of CD-MOF as their complete removal from frameworks is difficult. To avoid the use of above-mentioned modulators, herein, we demonstrate the synthesis of nanosized CD-MOF using triethylamine (TEA) as a modulator to reduce their size to ~254 nm. The MOF characteristics such as crystal and chemical structure remain unaffected and the surface area of CD-MOF synthesised with TEA is measured 1075.5 m2/g, almost 50 % higher than those of synthesised using bulky modulators. The improved CD-MOF architecture utilized for the in-situ synthesis of silver nanoparticles resulted in enhanced antimicrobial efficacy tested against Staphylococcus aureus and Escherichia coli bacteria and Candida albicans fungus. And minimum inhibitory concentration (MIC) is recorded in the range of 31–15 μg/mL. Overall, the structural improvement in CD-MOF supported with thorough comparative investigations and enhanced antimicrobial efficacy could be very helpful in further establishing them in biomedicine field.

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

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

Dialdehyde modification of laminarin for facile synthesis of ultrafine silver nanoparticles with excellent antibacterial and wound healing properties

Laminarin is a promising marine biopolymer that is abundant, non-toxic, and biodegradable. However, laminarin has a weak reduction potential for metal ions, resulting in the synthesis of a lower content of large-sized silver nanoparticles (AgNPs). Here, we showed that after the introduction of aldehyde groups, the reduction potential of laminarin increased, decreasing the synthesis time and increasing the density of AgNPs. 1H NMR and FT-IR confirmed the addition of aldehyde groups on laminarin. The dialdehyde-modified laminarin (DLAM) showed in situ, simple, and rapid synthesis of ultrasmall-sized spherical AgNPs (<10 nm), as revealed by TEM images. The aldehyde and carboxyl groups of DLAM act as synchronized reducing and anchoring agents. The conversion of Ag ions into AgNPs-DLAM was confirmed by UV–Vis spectrophotometer, FTIR, XRD, and XPS analysis. The AgNPs-DLAM showed significantly enhanced antibacterial activities than silver ions against Escherichia coli and Staphylococcus aureus via causing morphological changes and pore formations in bacterial cells. The AgNPs-DLAM also inhibited bacterial biofilm formation. In contrast, the AgNPs-DLAM showed negligible toxicity toward human keratinocytes. Furthermore, AgNPs-DLAM increased the migration of human keratinocytes, indicating efficient wound healing properties. Thus, signifying the importance of AgNPs-DLAM in clinical applications.

Silver nanoparticles biosynthesized from secondary metabolite producing marine actinobacteria and evaluation of their biomedical potential.

Biosynthesis of silver nanoparticles (AgNPs) from marine actinobacteria offers a promising avenue for exploring bacterial extracts as reducing and stabilizing agents. We report extracellular extracts of Rhodococcus rhodochrous (MOSEL-ME29) and Streptomyces sp. (MOSEL-ME28), identified by 16S rRNA gene sequencing for synthesis of AgNPs. Ultrafine silver nanoparticles were biosynthesized using the extracts of R. rhodochrous and Streptomyces sp. and their possible therapeutic applications were studied. The physicochemical properties of nanoparticles were established by HR-SEM/TEM, SAED, UV-Vis, EDS, XRD, and FTIR. UV-Vis spectra displayed characteristic absorption at 430nm and 412nm for AgNPs from Streptomyces sp. (S-AgNPs) and Rhodococcus sp. (R-AgNPs), respectively. HR-SEM/TEM, XRD, EDS analysis confirmed the spherical shape, crystalline nature, and elemental formation of silver. Crystallite or grain size was deduced as 5.52nm for R-AgNPs and 35nm for S-AgNPs. Zeta-potential indicated electrostatic negative charge for AgNPs, while FTIR revealed the presence of diverse functional groups. Disc diffusion assay indicated the broad-spectrum antibacterial potential of S-AgNPs with the maximum inhibition of B. subtilis while R-AgNPs revealed potency against P. aeruginosa at 10µg/mL concentration. Biogenic AgNPs revealed antileishmanial activity and the IC50 was calculated as 164µg/mL and 184µg/mL for R-AgNPs and S-AgNPs respectively. Similarly, the R-AgNPs and S-AgNPs revealed anti-cancer potential against HepG2 and the IC50 was calculated as 49µg/mL and 69µg/mL for R-AgNPs and S-AgNPs, respectively. Moreover, the antioxidant activity showed significant results. MTT assay on RD cells, L20B cells, and Hep-2C indicated intensification in viability by reducing the concentration of R-AgNPs and S-AgNPs. The R-AgNPs and S-AgNPs inhibited sabin-like poliovirus (1TCID50 infection in RD cells). Furthermore, hemocompatibility at low concentrations has been confirmed. Hence, it is concluded that biogenic-AgNPs has the potential to be used in diverse biological applications and that the marine actinobacteria are an excellent resource for fabrication of AgNPs.

Aluminum Metal–Organic Framework–Silver Nanoparticle Composites for Catalytic Reduction of Nitrophenols

Ultrafine silver (Ag) nanoparticles (NPs) were successfully loaded on a robust aluminum (Al) metal–organic framework (MOF), NOTT-300(Al), by means of a double-solvent method (DSM), and the construc...

Intensified photocatalytic degradation of 2, 4–dicholorophenoxyacetic acid using size-controlled silver nanoparticles: Effect of pre-synthesis extraction

In this study, ultrafine silver (Ag) nanoparticles were synthesised in Orthosiphon stamineus (OS) extract via facile electrochemical method. Different pre–synthesis extraction methods, namely ultrasonic assisted extraction hydro–distillation (UAE–HD) and classical aqueous extraction (AE) were used and compared. UAE–HD attained the highest total phenolic compounds at 8563.90 mg/kg. The Ag nanoparticles prepared via pre–synthesis extraction of UAE–HD (AgUAE-HD) and classical AE (AgAE) gave ultrafine sizes of 2 nm and 15 nm, respectively. It was suggested from the characterisation results that the phenolic compounds present in the OS extract had a significant role in the capping and stabilisation of Ag nanoparticles. Moreover, it was also demonstrated that the size of the Ag nanoparticles could simply be altered by varying the amount of total phenolic content (TPC) using different pre–synthesis extraction methods prior to the synthesis of Ag. Next, the photocatalytic activity of the Ag nanoparticles was tested towards the degradation of 2, 4–dicholorophenoxyacetic acid (2,4–D) herbicide. The synthesised Ag nanoparticles also showed outstanding photocatalytic activity with maximum degradation efficiency of up to 99.78% at pH 3, 0.01 g L−1 of catalyst dosage and 10 mg L−1 of 2, 4-D concentration. High amount of TPC contributed to the low energy band–gap (Eg) of AgUAE-HD catalyst and significantly inhibited the electron-hole recombination as well as enhanced the photocatalytic activity. The figures of merit based on electric energy consumption (EEO) indicate that less energy was consumed during the degradation of 2,4–D in the presence of AgUAE-HD compared with other catalysts. Therefore, it could be concluded that AgUAE-HD is a promising material for high photocatalytic degradation efficiency of 2,4–D under optimal condition.

Polydopamine assisted synthesis of ultrafine silver nanoparticles for heterogeneous catalysis and water remediation

Highly dispersed and ultrafine silver nanoparticles were synthesized on sepiolite nanofibres with polydopamine (Spl-PDA-Ag) and polyethyleneimine grafted polydopamine layers (Spl-PDA–PEI-Ag). The synthesized catalysts were thoroughly characterized to establish their chemical, structural, surface area, and morphology. The prepared catalysts were used for nitrophenol reduction and dye degradation in presence of sodium borohydride. Both catalysts showed exceptionally high catalytic efficiency for nitrophenol reduction with rate constants as high as 28.9 ×10−3 s−1 with turn over frequency 330 h−1. The Crystal violet and Methyl orange degradation performance was also considerably high with rate constant 6.6/7.3×10−3 s−1 and 6.5/7.1 ×10−3 s−1 for Spl-PDA-Ag and Spl-PDA–PEI-Ag, respectively. The high catalytic performance were obtained due to the synergistic effect of PDA/PEI layer with Ag nanoparticles. Apart from high catalytic activities, both catalysts show a very mild decrease in activity for over ten cycles of continuous reusability study, indicating their robustness and nonleaching from the substrates.

Cover: Journal of the Chinese Chemical Society 8/2019

In this paper, a facile, efficient and surfactantfree method to synthesize silica nanosphere supported ultrafine silver nanoparticles was developed. The antibacterial effects of the supported ultrafine silver nanoparticles with the ‘clean’ surface were evaluated against the Escherichia coli even at very low dosage accordingly to the bacterial viability measured by flow cytometry. More details about this figure will be discussed by Prof. Qihui Shen and his co‐workers on page 815–821 in this issue. image

A surfactant‐free synthesis of the silica nanosphere‐supported ultrafine silver nanoparticles and their antibacterial effects

AbstractIn this study, a facile, efficient, and surfactant‐free method to synthesize silica nanosphere‐supported ultrafine silver nanoparticles (AgNPs) (~2.5 nm) was developed, and their antibacterial effects were investigated. In the synthesis process, the hydrolysis of 3‐mercaptopropyltrimethoxysilane was adopted to provide thiol groups and in situ reduce Ag+ to Ag0 for ultrafine AgNPs formation on the surface of the silica nanosphere. Electron microscopy characterization of the complex formed revealed that the ultrafine AgNPs were not agglomerated and grow without any surfactants because there were no excess electrons transported from the shell to reduce the silver ions to silver atoms. The antibacterial effects of the supported ultrafine AgNPs with the surfactant‐free surface were evaluated against the Escherichia coli even at very low dosage. After incubation with 20 μg/mL silica‐supported AgNPs up to 120 min, 99.7% of the E. coli were inactivated, according to the bacterial viability measured by flow cytometry.

Ultrafine Silver Nanoparticles Embedded in Cyclodextrin Metal-Organic Frameworks with GRGDS Functionalization to Promote Antibacterial and Wound Healing Application.

The challenge of bacterial infection increases the risk of mortality and morbidity in acute and chronic wound healing. Silver nanoparticles (Ag NPs) are a promising new version of conventional antibacterial nanosystem to fight against the bacterial resistance in concern of the drug discovery void. However, there are several challenges in controlling the size and colloidal stability of Ag NPs, which readily aggregate or coalesce in both solid and aqueous state. In this study, a template-guided synthesis of ultrafine Ag NPs of around 2 nm using water-soluble and biocompatible γ-cyclodextrin metal-organic frameworks (CD-MOFs) is reported. The CD-MOF based synthetic strategy integrates AgNO3 reduction and Ag NPs immobilization in one pot achieving dual functions of reduced particle size and enhanced stability. Meanwhile, the synthesized Ag NPs are easily dispersible in aqueous media and exhibit effective bacterial inhibition. The surface modification of cross-linked CD-MOF particles with GRGDS peptide boosts the hemostatic effect that further enhances wound healing in synergy with the antibacterial effect. Hence, the strategy of ultrafine Ag NPs synthesis and immobilization in CD-MOFs together with GRGDS modification holds promising potential for the rational design of effective wound healing devices.

Ultrafine silver nanoparticles deposited on sodium-doped graphitic carbon nitride towards enhanced photocatalytic degradation of dyes and antibiotics under visible light irradiation

Ultrafine nanoparticle or single-atom deposition can improve the photocatalytic activity of graphitic carbon nitride (g-C3N4) efficiently. Herein, we prepared sodium ion-doped g-C3N4 photocatalyst deposited with ultrafine silver nanoparticles (<1 nm) by a facile and efficient one-pot route. Sodium sulfate was used as an inexpensive and green precursor to achieve the doping of sodium ions to g-C3N4. Ultrafine silver nanoparticles were anchored in-situ on the surface of g-C3N4 to construct Schottky heterojunction during thermal polycondensation. The band gap and valence band position of g-C3N4 were tuned by sodium ion doping, which enhanced visible light absorption and oxidizing ability. Both ultrafine silver nanoparticles and sodium ions accelerated the migration of photogenerated electrons and promoted the separation of photogenerated carries. These merits were synergistic to cause the excellent enhanced photocatalytic activity of sodium ion-doped g-C3N4 deposited with ultrafine silver nanoparticles in degradation of Rhodamine B and tetracycline hydrochloride under visible light irradiation.

Ultrafine silver nanoparticles supported on a covalent carbazole framework as high-efficiency nanocatalysts for nitrophenol reduction

A novel covalent micro/macro-porous polymer (CMP), CZ–TEB, is synthesized and then Ag NPs are immobilized on it, and the normalized rate constant (knor) of the Ag0@CZ–TEB catalyzed reduction reaction of 4-NP to 4-AP reaches up to 21.49 mmol−1 s−1.

Synthesis of Ultrafine Silver Nanoparticles on the Surface of Fe3O4@SiO2@KIT-6-NH2 Nanocomposite and Their Application as a Highly Efficient and Reusable Catalyst for Reduction of Nitrofurazone and Aromatic Nitro Compounds Under Mild Conditions

Uniform dispersion of ultrafine spherical silver nanoparticles (NPs) was obtained over the surface of Fe3O4@SiO2@KIT-6 core–shell support via functionalization of the mesoporous KIT-6 shell by aminopropyltriethoxysilane, followed by coordination of Ag+ ions and in situ chemical reduction with sodium borohydride. The obtained hybrid material, Fe3O4@SiO2@KIT-6-Ag nanocomposite, was fully characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, and used as an efficient catalyst for selective reduction of nitroaromatic compounds in aqueous solution at ambient temperature and neutral pH [nine examples, apparent rate constants at 25 °C, k (min−1), 0.112–0.628]. As a non-aromatic example, nitrofurazone which is a cytotoxic antibiotic was also reduced selectively at nitro group without reduction of other functionalities. Fe3O4@SiO2@KIT-6-Ag NPs also showed potential ability to act as catalyst for reduction of nitromethane in aqueous solution which can provide a colorimetric method for detection of nitromethane in solution down to 0.9 × 10−4 mol L−1. Fe3O4@SiO2@KIT-6-Ag nanocomposite was also screened for its antibacterial activity, and satisfactory results were obtained in comparison with drug references including Tetracycline, Chloramphenicol and Cefotaxime as positive controls, on gram negative Escherichia coli and Pseudomonas aeroginosa. Ease of recycling of the Fe3O4@SiO2@KIT-6-Ag is another benefit of this nanocatalyst. Under the optimized conditions, the recycled catalyst showed 15% loss of efficiency after five successive runs.