Viral disinfection using nonthermal plasma: A critical review and perspectives on the plasma-catalysis system

The transmission of viral infections via aerosol has become a serious threat to public health. This has produced an ever-increasing demand for effective forms of viral inactivation technology/processes. Plasma technology is rising in popularity and gaining interest for viral disinfection use. Due to its highly effectively disinfection and flexible operation, non-thermal plasma (NTP) is a promising technology in decontaminating bacteria or virus from air or surfaces. This review discusses the fundamentals of non-thermal plasma and the disinfection mechanisms of the biocidal agents produced in plasma, including ultraviolet (UV) photons, reactive oxygen species, and reactive nitrogen species. Perspectives on the role of catalysts and its potential applications in cold plasma disinfection are discussed.

A critical review on the existing wastewater treatment methods in the COVID-19 era: What is the potential of advanced oxidation processes in combatting viral especially SARS-CoV-2?

The COVID-19 epidemic has put the risk of virus contamination in water bodies on the horizon of health authorities. Hence, finding effective ways to remove the virus, especially SARS-CoV-2, from wastewater treatment plants (WWTPs) has emerged as a hot issue in the last few years. Herein, this study first deals with the fate of SARS-CoV-2 genetic material in WWTPs, then critically reviews and compares different wastewater treatment methods for combatting COVID-19 as well as to increase the water quality. This critical review sheds light the efficiency of advanced oxidation processes (AOPs) to inactivate virus, specially SARS-CoV-2 RNA. Although several physicochemical treatment processes (e.g. activated sludge) are commonly used to eliminate pathogens, AOPs are the most versatile and effective virus inactivation methods. For instance, TiO₂ is the most known and widely studied photo-catalyst innocuously utilized to degrade pollutants as well as to photo-induce bacterial and virus disinfection due to its high chemical resistance and efficient photo-activity. When ozone is dissolved in water and wastewater, it generates a wide spectrum of the reactive oxygen species (ROS), which are responsible to degrade materials in virus membranes resulting in destroying the cell wall. Furthermore, electrochemical advanced oxidation processes act through direct oxidation when pathogens react at the anode surface or by indirect oxidation through oxidizing species produced in the bulk solution. Consequently, they represent a feasible choice for the inactivation of a wide range of pathogens. Nonetheless, there are some challenges with AOPs which should be addressed for application at industrial-scale.

Bactericidal activity of immobilized silver nanoparticles on silica substrates with different sizes

Hybrid particles with immobilized silver nanoparticles (AgNPs) receive a lot of attention due to their excellent antibacterial activity with the prevention of inherent aggregation of AgNPs. In this study, serial sized silica substrate particles (231, 401, and 605 nm) and their corresponding hybrid particles with AgNPs (~ 30 nm) are prepared, with detailed bactericidal images of the corresponding particles at various times. Their bactericidal activity is elucidated for both Gram-positive Streptococcus agalactiae and Gram-negative Escherichia coli CN13, which show the size of 0.8 μm × 0.9 μm and 1.3 μm × 1.8 μm, respectively. There is a large difference in the bactericidal activity between the smallest (231 nm, 3-log₁₀ reduction) and larger (401 and 605 nm, 6-log₁₀ reduction) silica substrates, whereas there is hardly a difference between the latter. Their effective total surface area (ETSA) is considered important for their bactericidal activity, based on the nearly equal large ETSA of the well-dispersed two larger silica substrates and the much smaller ETSA of the agglomerated smallest substrates. Submicron-sized pits appear on the bacterial membrane by direct contact with the hybrid particles, implicating the importance of ETSA. Still, further research is needed with much different silica substrate sizes to fully elucidate the impact of the silica substrate on the bactericidal activity of immobilized AgNPs.

Proposed approaches for coronaviruses elimination from wastewater: Membrane techniques and nanotechnology solutions

Since the beginning of the third Millennium, specifically during the last 18 years, three outbreaks of diseases have been recorded caused by coronaviruses (CoVs). The latest outbreak of these diseases was Coronavirus Disease 2019 (COVID-19), which has been declared by the World Health Organization (WHO) as a pandemic. For this reason, current efforts of the environmental, epidemiology scientists, engineers, and water sector professionals are ongoing to detect CoV in environmental components, especially water, and assess the relative risk of exposure to these systems and any measures needed to protect the public health, workers, and public, in general. This review presents a brief overview of CoV in water, wastewater, and surface water based on a literature search providing different solutions to keep water protected from CoV. Membrane techniques are very attractive solutions for virus elimination in water. In addition, another essential solution is nanotechnology and its applications in the detection and protection of human and water systems.

Antiviral nanoparticles for sanitizing surfaces: A roadmap to self-sterilizing against COVID-19

Nanoparticles provide new opportunities in merging therapeutics and new materials, with current research efforts just beginning to scratch the surface of their diverse benefits and potential applications. One such application, the use of inorganic nanoparticles in antiseptic coatings to prevent pathogen transmission and infection, has seen promising developments. Notably, the high reactive surface area to volume ratio and unique chemical properties of metal-based nanoparticles enables their potent inactivation of viruses. Nanoparticles exert their virucidal action through mechanisms including inhibition of virus-cell receptor binding, reactive oxygen species oxidation and destructive displacement bonding with key viral structures. The prevention of viral outbreaks is one of the foremost challenges to medical science today, emphasizing the importance of research efforts to develop nanoparticles for preventative antiviral applications. In this review, the use of nanoparticles to inactivate other viruses, such as influenza, HIV-1, or norovirus, among others, will be discussed to extrapolate broad-spectrum antiviral mechanisms that could also inhibit SARS-CoV-2 pathogenesis. This review analyzes the published literature to highlight the current state of knowledge regarding the efficacy of metal-based nanoparticles and other antiviral materials for biomedical, sterile polymer, and surface coating applications.

Green synthesized plant-based silver nanoparticles: therapeutic prospective for anticancer and antiviral activity

Nanotechnology holds an emerging domain of medical science as it can be utilized virtually in all areas. Phyto-constituents are valuable and encouraging candidates for synthesizing green silver nanoparticles (AgNPs) which possess great potentials toward chronic diseases. This review gives an overview of the Green approach of AgNPs synthesis and its characterization. The present review further explores the potentials of Phyto-based AgNPs toward anticancer and antiviral activity including its probable mechanism of action. Green synthesized AgNPs prepared by numerous medicinal plants extract are critically reviewed for cancer and viral infection. Thus, this article mainly highlights green synthesized Phyto-based AgNPs with their potential applications for cancer and viral infection including mechanism of action and therapeutic future prospective in a single window.

A review on recent trends of antiviral nanoparticles and airborne filters: special insight on COVID-19 virus

Novel corona virus (COVID-19) pandemic in the last 4 months stimulates the international scientific community to search for vaccine of antiviral agents suitable for in activating the virus inside and outside the human body. More than 4 million people globally are infected by the virus and about 300,000 dead cases until this moment. The ventilation and airborne filters are also investigated aiming to develop an efficient antiviral filtration technology. Human secretion of the infected person as nasal or saliva droplets goes as airborne and distributes the virus everywhere around the person. N95 and N98 filters are the must use filters for capturing particles of sizes around 300 nm. The average size of the novel corona virus (COVID-19) is 100 nm and there is no standard or special filter suitable for this virus. The nanoparticle-coated airborne filter is a suitable technique in this regard. While the efficiency of this type of filters still needs to be enhanced, new developed nanofiber filters are proposed. Most recently, the charged nanofiber filters of sizes below 100 nm are developed and provide an efficient viral filtration and inactivation. The efficiency of filter must be kept at accepted level without increasing the pressure drop. The present review outlines the most efficient antiviral nanoparticles including the recent functional nanoparticles. The filtration theory, filtration modeling, filter testing, and different types of filter with special concentration on the charged nanofiber filter were discussed. The charged nanofiber filter able to capture novel corona virus (COVID-19) with 94% efficiency and a pressure drop less than 20 MPa.

GSH-ZnS Nanoparticles Exhibit High-Efficiency and Broad-Spectrum Antiviral Activities via Multistep Inhibition Mechanisms

Despite the good biocompatibility and antibacterial activity of zinc sulfide nanoparticles (ZnS NPs), whether they possess antiviral activity is still unclear. Here, GSH-modified ZnS NPs (GSH-ZnS NPs) were synthesized and their significant antiviral activity was demonstrated using the Arteriviridae family RNA virus, porcine reproductive and respiratory syndrome virus (PRRSV), as a model. Mechanistically, GSH-ZnS NPs were shown to reduce PRRSV-induced ROS production to prevent PRRSV multiplication, with no activating effect on the interferon (IFN) signal pathway, the first defense line against virus infection. Furthermore, isobaric tags for relative and absolute quantification (iTRAQ)-based quantitative proteomic analysis of GSH-ZnS NP-treated cells revealed the involvement of numerous crucial proteins in virus proliferation, with vitronectin (VTN) being confirmed as an efficient PRRSV antagonist here. Furthermore, GSH-ZnS NPs were found to have potent antiviral effects on the Herpesviridae family DNA virus, pseudorabies virus (PRV), the Coronaviridae family positive-sense RNA virus, porcine epidemic diarrhea virus (PEDV), and the Rhabdoviridae family negative-stranded RNA virus, vesicular stomatitis virus (VSV), indicating their broad-spectrum antiviral activity against viruses from different families with various genome types. Overall, GSH-ZnS NP is a prospective candidate for the development of antiviral nanomaterials and may serve as a model for investigation of potential host restriction factors in combination with proteomics.

Antimicrobial Bilayer Nanocomposites Based on the Incorporation of As-Synthetized Hollow Zinc Oxide Nanotubes

An antimicrobial polymeric bilayer structure based on the application of an acrylic coating containing hollow zinc oxide nanotubes over a polymeric substrate was developed in this work. Firstly, zinc oxide nanotubes (ZnO_NT) were obtained by an atomic layer deposition (ALD) process over electrospun polyvinyl alcohol nanofibers followed by polymer removal through calcination with the purpose of obtaining antimicrobial nanostructures with a high specific area. Parameters of electrospinning, ALD, and calcination processes were set in order to obtain successfully hollow zinc oxide nanotubes. Morphological studies through scanning electron microscopy (SEM) and transmission electron microscopy (TEM) microscopies confirmed the morphological structure of ZnO_NT with an average diameter of 180 nm and thickness of approximately 60 nm. Thermal and X-ray diffraction (XRD) analyses provided evidence that calcination completely removed the polymer, resulting in a crystalline hexagonal wurtzite structure. Subsequently, ZnO_NT were incorporated into a polymeric coating over a polyethylene extruded film at two concentrations: 0.5 and 1 wt. % with respect to the polymer weight. An antimicrobial analysis of developed antimicrobial materials was performed following JIS Z2801 against Staphylococcus aureus and Escherichia coli. When compared to active materials containing commercial ZnO nanoparticles, materials containing ZnO_NT presented higher microbial inhibition principally against Gram-negative bacteria, whose reduction was total for films containing 1 wt. % ZnO_NT. Antiviral studies were also performed, but these materials did not present significant viral reduction.

Inactivation of influenza A virus via exposure to silver nanoparticle-decorated silica hybrid composites

Influenza A virus (IFV-A) is one of the main cause of seasonal flu and can infect various of host species via the reassortment of segmented RNA genomes. Silver nanoparticles (AgNPs) have been known as excellent antiviral agent against IFV. However, the use of free AgNPs has several major drawbacks, including the inherent aggregation among AgNPs and unwanted cytotoxic or genotoxic damages for human body via inhalation or ingestion. In this study, we assessed the efficacy of our novel ~ 30-nm-diameter AgNP-decorated silica hybrid composite (Ag30-SiO₂; ~ 400 nm in diameter) for IFV-A inactivation. Ag30-SiO₂ particles can inhibit IFV-A effectively in a clear dose-dependent manner. However, when real-time RT-PCR assay was used, merely 0.5-log₁₀ reduction of IFV-A was observed at both 5 and 20 °C. Moreover, even after 1 h of exposure to Ag30-SiO₂ particles, more than 80% of hemagglutinin (HA) damage and 20% of neuraminidase (NA) activities had occurred, and the infection of Madin-Darby Canine Kidney (MDCK) cells by IFV-A was reduced. The results suggested that the major antiviral mechanism of Ag30-SiO₂ particles is the interaction with viral components located at the membrane. Therefore, Ag30-SiO₂ particles can cause nonspecific damage to various IFV-A components and be used as an effective method for inactivating IFV-A.

Disinfection of waterborne viruses using silver nanoparticle-decorated silica hybrid composites in water environments

Silver nanoparticles (AgNPs) have been reported as an effective alternative for controlling a broad-spectrum of pathogenic viruses. We developed a micrometer-sized silica hybrid composite decorated with AgNPs (AgNP-SiO₂) to prevent the inherent aggregation of AgNPs, and facilitated their recovery from environmental media after use. The production process had a high-yield, and fabrication was cost-effective. We evaluated the antiviral capabilities of Ag30-SiO₂ particles against two model viruses, bacteriophage MS2 and murine norovirus (MNV), in four different types of water (deionized, tap, surface, and ground). MNV was more susceptible to Ag30-SiO₂ particles in all four types of water compared to MS2. Furthermore, several water-related factors, including temperature and organic matter content, were shown to affect the antimicrobial capabilities of Ag30-SiO₂ particles. The modified Hom model was the best-fit disinfection model for MNV disinfection in the different types of water. Additionally, this study demonstrated that the effects of a certain level of physical obstacles in water were negligible in regards to the use of Ag30-SiO₂ particles. Thus, effective use of AgNPs in water disinfection processes can be achieved using our novel hybrid composites to inactivate various waterborne viruses.

Disinfection of various bacterial pathogens using novel silver nanoparticle-decorated magnetic hybrid colloids

Silver nanoparticles (AgNPs) have long been considered a powerful disinfectant for controlling pathogenic microorganisms. However, AgNPs might have adverse effects on both human health and our ecosystems due to their potential cytotoxicity and the difficulty in recovering them after their release into the environment. In this study, we characterized the antimicrobial efficacy caused by a novel micrometer-sized magnetic hybrid colloid (MHC) containing 7, 15, or 30nm sized monodispersed AgNPs (AgNP-MHCs), which can be re-collected from the environment using simple procedures, such as a magnet or centrifugation. We evaluated the antibacterial capabilities of AgNP-MHCs against target bacteria (Legionella pneumophila, Bacillus subtilis, Escherichia coli, and Clostridium perfringens) and compared them with the inactivation efficacy of AgNPs ~30nm in diameter (nAg30s). Among the different AgNP-MHCs composites evaluated, Ag30-MHCs had the greatest antibacterial effect. After 1h of exposure, more than a 4-log₁₀ reduction of L. pneumophila and 6-log₁₀ reduction of B. subtilis was achieved by 4.6×10⁹particles/mL of Ag30-MHCs and Ag30-MHC-Ls. In addition, Ag30-MHC-Ls maintained their strong antibacterial capabilities under anaerobic conditions. Our results indicate that AgNP-MHCs can be considered excellent tools for controlling waterborne bacterial pathogens, with a minimal risk of release into the environment.

Luminescent Silver-Purine Double Helicate: Synthesis, Self-Assembly and Antibacterial Action

The synthesis, self-assembly and antibacterial activity of a luminescent silver-purine double helicate is reported. The structure of the newly synthesized silver-supported helicate [C₃₆ H₂₄ N₁₆ O₄ Cl₅ Ag₁ ] was unambiguously characterized by single-crystal X-ray crystallography. It exhibited a bright bluish-green emission (λ_max =460 nm), when excited with 380 nm light. Microscopic investigations showed that the complex has a propensity to self-assemble into nanospheres. The antibacterial activity of this silver-containing helicate was studied against both Gram-positive and Gram-negative bacteria. MIC (minimal inhibitory concentration) values showed that the complex is very active against Gram-negative bacteria. Further internalization of the silver complex into E. coli bacteria was mapped with the help of microscopic techniques. These results are significant as silver was recently found to enhance antibiotic action against Gram-negative bacteria, raising hope in countering severe bacterial infections.

Silver Nanoparticle Based Codelivery of Oseltamivir to Inhibit the Activity of the H1N1 Influenza Virus through ROS-Mediated Signaling Pathways

As the therapeutic agent for antiviral applications, the clinical use of oseltamivir is limited with the appearance of drug-resistant viruses. It is important to explore novel anti-influenza drugs. The antiviral activity of silver nanoparticles (AgNPs) has attracted increasing attention in recent years and was a possibility to be employed as a biomedical intervention. Herein, we describe the synthesis of surface decoration of AgNPs by using oseltamivir (OTV) with antiviral properties and inhibition of drug resistance. Compared to silver and oseltamivir, oseltamivir-modified AgNPs (Ag@OTV) have remarkable inhibition against H1N1 infection, and less toxicity was found for MDCK cells by controlled-potential electrolysis (CPE), MTT, and transmission electron microscopy (TEM). Furthermore, Ag@OTV inhibited the activity of neuraminidase (NA) and hemagglutinin (HA) and then prevented the attachment of the H1N1 influenza virus to host cells. The investigations of the mechanism revealed that Ag@OTV could block H1N1 from infecting MDCK cells and prevent DNA fragmentation, chromatin condensation, and the activity of caspase-3. Ag@OTV remarkably inhibited the accumulation of reactive oxygen species (ROS) by the H1N1 virus and activation of AKT and p53 phosphorylation. Silver nanoparticle based codelivery of oseltamivir inhibits the activity of the H1N1 influenza virus through ROS-mediated signaling pathways. These findings demonstrate that Ag@OTV is a novel promising efficient virucide for H1N1.

Silk Fiber as the Support and Reductant for the Facile Synthesis of Ag-Fe₃O₄ Nanocomposites and Its Antibacterial Properties

We report a facile and environmentally friendly approach to prepare Ag-Fe₃O₄-silk fiber nanocomposites. The Ag-Fe₃O₄-silk fiber acts as: (i) a biocompatible support for the silver nanoparticles; and (ii) a reducing agent for the silver ions. Neither additional reducing agents nor toxic organic solvents were used during the preparation process. The Ag-Fe₃O₄-silk fiber nanocomposites can be actuated by a small household magnet and have high antibacterial activities against both Escherichia coli and Staphylococcus aureus. These nanocomposites could be easily recycled without a decrease in their antibacterial activities due to the synergistic effects between the Ag NPs and Fe₃O₄ NPs with large amounts of active sites.

Reversal of H1N1 influenza virus-induced apoptosis by silver nanoparticles functionalized with amantadine

Reversal of H1N1 influenza virus-induced apoptosis by silver nanoparticles functionalized with amantadine.

Bactericidal mechanisms revealed for rapid water disinfection by superabsorbent cryogels decorated with silver nanoparticles

The authors have recently reported the fabrication of superabsorbent cryogels decorated with silver nanoparticles (PSA/AgNP cryogels) that demonstrate rapid water disinfection. This paper provides a systematic elucidation of the bactericidal mechanisms of AgNPs (silver nanoparticles), both generally and in the specific context of cryogels. Direct contact between the PSA/AgNP cryogel interface and the bacterial cells is required to accomplish disinfection. Specifically, the disinfection efficacy is closely correlated to the cell-bound Ag concentration, which constitutes >90% of the Ag released. Cells exposed to PSA/AgNP cryogels show a significant depletion of intracellular adenosine triphosphate (ATP) content and cell-membrane lesions. A positive ROS (reactive oxygen species) scavenging test confirms the involvement of ROS (·O2(-), H2O2, and ·OH) in the bactericidal mechanism. Furthermore, exposed bacterial cells show an enhanced level of thiobarbituric acid reactive substances, indicating the occurrence of cell-membrane peroxidation mediated by ROS. In addition, this study reveals that both Ag(+) and Ag(0) are involved in the bactericidal mechanism of AgNPs via tests conducted using PSA cryogels with bound Ag(+) ions (or PSA/Ag(+) cryogels without reducing Ag(+) to Ag(0)). Significantly, bacterial cells exposed to PSA/Ag(+) cryogels did not show any cell-membrane damage even though the former had a higher cell-bound Ag concentration than that of the PSA/AgNP cryogels, thus indicating the differential action of Ag(+) and Ag(0).

A facile ultrasonication assisted method for Fe3O4@SiO2-Ag nanospheres with excellent antibacterial activity

A novel ultrasonication assisted method was developed to synthesize monodisperse Fe₃O₄@SiO₂-Ag nanospheres which exhibited excellent antibacterial activities against bothStaphylococcus aureusandEscherichia coli.

Facile synthesis of water soluble silver ferrite (AgFeO2) nanoparticles and their biological application as antibacterial agents

The syntheses and antibacterial activity of AgFeO₂ and AgFO₂ modified polyethylene glycols are reported.

Fabrication of an anti-viral air filter with SiO₂-Ag nanoparticles and performance evaluation in a continuous airflow condition

In this study, SiO2 nanoparticles surface coated with Ag nanoparticles (SA particles) were fabricated to coat a medium air filter. The pressure drop, filtration efficiency, and anti-viral ability of the filter were evaluated against aerosolized bacteriophage MS2 in a continuous air flow condition. A mathematical approach was developed to measure the anti-viral ability of the filter with various virus deposition times. Moreover, two quality factors based on the anti-viral ability of the filter, and a traditional quality factor based on filtration efficiency, were calculated. The filtration efficiency and pressure drop increased with decreasing media velocity and with increasing SA particle coating level. The anti-viral efficiency also increased with increasing SA particle coating level, and decreased by with increasing virus deposition time. Consequently, SA particle coating on a filter does not have significant effects on filtration quality, and there is an optimal coating level to produce the highest anti-viral quality.

A hybrid antioxidizing and antibacterial material based on Ag-La2O3 nanocomposites

The Ag-La2O3 hybrid nanoparticles were prepared by loading Ag nanoparticles on the surface of the La2O3 nanorods. The synthesis was a one-step process where sodium borohydride was used as a reducing agent to convert silver ions into silver nanoparticles, which were further deposited on the La2O3 nanorods. Moreover, they were found evenly dispersed upon the surface of La2O3 supports. The as-prepared Ag-La2O3 nanocomposites showed anti-oxidizing and significant antibacterial effect in vitro. Using the results from transmission electron microscope (TEM), the plausible mechanism was also proposed to explain the inhibition of bacterial growth. The present strategy can be potentially extended to develop drug-labels and other antibacterial agents.

Antiviral properties of silver nanoparticles on a magnetic hybrid colloid

Silver nanoparticles (AgNPs) are considered to be a potentially useful tool for controlling various pathogens. However, there are concerns about the release of AgNPs into environmental media, as they may generate adverse human health and ecological effects. In this study, we developed and evaluated a novel micrometer-sized magnetic hybrid colloid (MHC) decorated with variously sized AgNPs (AgNP-MHCs). After being applied for disinfection, these particles can be easily recovered from environmental media using their magnetic properties and remain effective for inactivating viral pathogens. We evaluated the efficacy of AgNP-MHCs for inactivating bacteriophage ΦX174, murine norovirus (MNV), and adenovirus serotype 2 (AdV2). These target viruses were exposed to AgNP-MHCs for 1, 3, and 6 h at 25°C and then analyzed by plaque assay and real-time TaqMan PCR. The AgNP-MHCs were exposed to a wide range of pH levels and to tap and surface water to assess their antiviral effects under different environmental conditions. Among the three types of AgNP-MHCs tested, Ag30-MHCs displayed the highest efficacy for inactivating the viruses. The ΦX174 and MNV were reduced by more than 2 log10 after exposure to 4.6 × 10(9) Ag30-MHCs/ml for 1 h. These results indicated that the AgNP-MHCs could be used to inactivate viral pathogens with minimum chance of potential release into environment.

Silver nanoparticle–ionic silsesquioxane: a new system proposed as an antibacterial agent

Ionic silsesquioxane applied as a stabilizer of small size silver nanoparticle aqueous dispersions showing antibacterial activity at very low concentration.

Prompt and synergistic antibacterial activity of silver nanoparticle-decorated silica hybrid particles on air filtration

Silver nanoparticle-decorated silica hybrid particles (AgNP@SiO₂) bite away bacteria promptly and synergistically upon contact by air filtration.

Ag@Fe2O3-GO nanocomposites prepared by a phase transfer method with long-term antibacterial property

Silver has been utilized as a highly effective and broad-spectrum antibacterial agent in our daily life. However, low stability, poor long-term antibacterial efficiency, and potential environmental hazard of released Ag(+) ions may limit its practical applications. Ag-graphene oxide (GO) nanocomposites have been reported to display highly enhanced antibacterial property, yet their stability and long-term antibacterial properties have not been carefully investigated. Herein, we report the synthesis of Ag@Fe2O3-GO nanocomposites with tunable loading density up to full monolayer coverage by adopting a simple phase transfer method. Compared to Ag@Fe2O3, its GO composite shows enhanced stability with Ag(+) releasing rate decreased by more than two times under dialysis condition. We discover that the presence of GO not only slows down Ag nanoparticle oxidation process but also enables Ag(+) ions recrystallization on GO surface. The Ag@Fe2O3-GO nanocomposites have shown better and long-term antibacterial property against both Gram-negative and Gram-positive bacteria than those of plain Ag and Ag@Fe2O3, displaying great potential as a promising long-term bactericide with suppressed environmental hazard.