Removal of bacteriophage f2 in water by Fe/Ni nanoparticles: Optimization of Fe/Ni ratio and influencing factors

Membrane modification in enhancement of virus removal: A critical review

Many waterborne diseases are related with viruses, and COVID-19 worldwide has raised the concern of virus security in water into the public horizon. Compared to other conventional water treatment processes, membrane technology can achieve satisfactory virus removal with fewer chemicals, and prevent the outbreaks of viruses to a maximal extent. Researchers developed new modification methods to improve membrane performance. This review focused on the membrane modifications that enhance the performance in virus removal. The characteristics of viruses and their removal by membrane filtration were briefly generalized, and membrane modifications were systematically discussed through different virus removal mechanisms, including size exclusion, hydrophilic and hydrophobic interactions, electronic interactions, and inactivation. Advanced functional materials for membrane modification were summarized based on their nature. Furthermore, it is suggested that membranes should be enhanced through different mechanisms mainly based on their ranks of pore size. The current review provided theoretical support regarding membrane modifications in the enhancement of virus removal and avenues for practical application.

Analysis of the Degradation of OCPs Contaminated Soil by the BC/nZVI Combined with Indigenous Microorganisms

Organochlorine pesticides (OCPs) were typical persistent organic pollutants that posed great hazards and high risks in soil. In this study, a peanut shell biochar-loaded nano zero-valent iron (BC/nZVI) material was prepared in combination with soil indigenous microorganisms to enhance the degradation of α-hexachlorocyclohexane(α-HCH) and γ-hexachlorocyclohexane(γ-HCH) in water and soil. The effects of BC/nZVI on indigenous microorganisms in soil were investigated based on the changes in redox potential and dehydrogenase activity in the soil. The results showed as follows: (1) The specific surface area of peanut shell biochar loaded with nano-zero-valent iron was large, and the nano-zero-valent iron particles were evenly distributed on the peanut shell biochar; (2) peanut shell BC/nZVI had a good degradation effect on α-HCH and γ-HCH in water, with degradation rates of 64.18% for α-HCH and 91.87% for γ-HCH in 24 h; (3) peanut shell BC/nZVI also had a good degradation effect on α-HCH and γ-HCH in soil, and the degradation rates of α-HCH and γ-HCH in the 1% BC/nZVI reached 55.2% and 85.4%, second only to 1% zero-valent iron. The degradation rate was the fastest from 0 to 7 days, while the soil oxidation-reduction potential (ORP) increased sharply. (4) The addition of BC/nZVI to the soil resulted in a significant increase in dehydrogenase activity, which further promoted the degradation of HCHs; the amount of HCHs degradation was significantly negatively correlated with dehydrogenase activity. This study provides a remediation strategy for HCH-contaminated sites, reducing the human health risk of HCHs in the soil while helping to improve the soil and increase the activity of soil microorganisms.

How to Tackle Bacteriophages: The Review of Approaches with Mechanistic Insight

Bacteriophage-based applications have a renaissance today, increasingly marking their use in industry, medicine, food processing, biotechnology, and more. However, phages are considered resistant to various harsh environmental conditions; besides, they are characterized by high intra-group variability. Phage-related contaminations may therefore pose new challenges in the future due to the wider use of phages in industry and health care. Therefore, in this review, we summarize the current knowledge of bacteriophage disinfection methods, as well as highlight new technologies and approaches. We discuss the need for systematic solutions to improve bacteriophage control, taking into account their structural and environmental diversity.

Peptide-Grafted Nontoxic Cyclodextrins and Nanoparticles against Bacteriophage Infections

One of the biggest threats for bacteria-based bioreactors in the biotechnology industry is infections caused by bacterial viruses called bacteriophages. More than 70% of companies admitted to encountering this problem. Despite phage infections being such a dangerous and widespread risk, to date, there are no effective methods to avoid them. Here we present a peptide-grafted compounds that irreversibly deactivate bacteriophages and remain safe for bacteria and mammalian cells. The active compounds consist of a core (cyclodextrin or gold nanoparticle) coated with a hydrophobic chain terminated with a peptide selective for bacteriophages. Such peptides were selected via a phage display technique. This approach enables irreversible deactivation of the wide range of T-like phages (including the most dangerous in phage infections, phage T1) at 37 °C in 1 h. We show that our compounds can be used directly inside the environment of the bioreactor, but they are also a safe additive to stocks of antibiotics and expression inducers (such as isopropyl β-d-1-thiogalactopyranoside, i.e., IPTG) that cannot be autoclaved and are a common source of phage infections.

Chemical Nature of Metals and Metal-Based Materials in Inactivation of Viruses

In response to the enormous threat to human survival and development caused by the large number of viruses, it is necessary to strengthen the defense against and elimination of viruses. Metallic materials have been used against viruses for thousands of years due to their broad-spectrum antiviral properties, wide sources and excellent physicochemical properties; in particular, metal nanoparticles have advanced biomedical research. However, researchers in different fields hold dissimilar views on the antiviral mechanisms, which has slowed down the antiviral application of metal nanoparticles. As such, this review begins with an exhaustive compilation of previously published work on the antiviral capacity of metal nanoparticles and other materials. Afterwards, the discussion is centered on the antiviral mechanisms of metal nanoparticles at the biological and physicochemical levels. Emphasis is placed on the fact that the strong reducibility of metal nanoparticles may be the main reason for their efficient inactivation of viruses. We hope that this review will benefit the promotion of metal nanoparticles in the antiviral field and expedite the construction of a barrier between humans and viruses.

The Effect of Zero-Valent Iron Nanoparticles (nZVI) on Bacteriophages

Bacteriophages are viruses that attack and usually kill bacteria. Their appearance in the industrial facilities using bacteria to produce active compounds (e.g., drugs, food, cosmetics, etc.) causes considerable financial losses. Instances of bacteriophage resistance towards disinfectants and decontamination procedures (such as thermal inactivation and photocatalysis) have been reported. There is a pressing need to explore new ways of phage inactivation that are environmentally neutral, inexpensive, and more efficient. Here, we study the effect of zero-valent iron nanoparticles (nZVI) on four different bacteriophages (T4, T7, MS2, M13). The reduction of plaque-forming units (PFU) per mL varies from greater than 7log to around 0.5log depending on bacteriophages (M13 and T7, respectively). A comparison of the importance of oxidation of nZVI versus the release of Fe²⁺/Fe³⁺ ions is shown. The mechanism of action is proposed in connection to redox reactions, adsorption of virions on nZVI, and the effect of released iron ions. The nZVI constitutes a critical addition to available antiphagents (i.e., anti-bacteriophage agents).

Broad-spectrum nanoparticles against bacteriophage infections

Viral infections caused by bacteriophages, i.e., viruses that kill bacteria are one of the most dangerous and common threats for bacteria-based bioreactors. More than 70% of biotechnology companies have admitted to encountering this problem. Despite phage infections being such a dangerous and widespread risk, there are no effective methods to avoid them to date. Herein, we present a novel technology based on nanoparticles that irreversibly deactivates bacteriophages and is safe for bacteria. Our method allows for the unsupervised protection of bacterial processes in the biotechnology industry. Gold nanoparticles coated with a mixture of negatively charged 11-mercapto 1-undecanesulfonic acid (MUS) and hydrophobic 1-octanethiol (OT) ligands are effective at deactivating various types of Escherichia coli-selective phages: T1, T4, and T7. The nanoparticles can lower the titer of phages up to 2 and 5 logs in 6 and 24 h at 50 °C, respectively. A comparative analysis of nanoparticles with different ligand shells illustrates the importance of the combination of negatively charged and hydrophobic ligands that is the key to achieving a good inhibitory concentration (EC50 ≤ 1 μg mL-1) for all tested phages. We show that the nanoparticles are harmless for the commonly used bacteria in industry Escherichia coli and are effective under conditions simulating the environment of bioreactors.

Gold-Polyoxoborates Nanocomposite Prohibits Adsorption of Bacteriophages on Inner Surfaces of Polypropylene Labware and Protects Samples from Bacterial and Yeast Infections

Bacteriophages (phages) are a specific type of viruses that infect bacteria. Because of growing antibiotic resistance among bacterial strains, phage-based therapies are becoming more and more attractive. The critical problem is the storage of bacteriophages. Recently, it was found that bacteriophages might adsorb on the surfaces of plastic containers, effectively decreasing the titer of phage suspensions. Here, we showed that a BOA nanocomposite (gold nanoparticles embedded in polyoxoborate matrix) deposited onto the inner walls of the containers stabilizes phage suspensions against uncontrolled adsorption and titer decrease. Additionally, BOA provides antibacterial and antifungal protection. The application of BOA assures safe and sterile means for the storage of bacteriophages.

Make it clean, make it safe: A review on virus elimination via adsorption

Recently, the potential dangers of viral infection transmission through water and air have become the focus of worldwide attention, via the spread of COVID-19 pandemic. The occurrence of large-scale outbreaks of dangerous infections caused by unknown pathogens and the isolation of new pandemic strains require the development of improved methods of viruses' inactivation. Viruses are not stable self-sustaining living organisms and are rapidly inactivated on isolated surfaces. However, water resources and air can participate in the pathogens' diffusion, stabilization, and transmission. Viruses inactivation and elimination by adsorption are relevant since they can represent an effective and low-cost method to treat fluids, and hence limit the spread of pathogen agents. This review analyzed the interaction between viruses and carbon-based, oxide-based, porous materials and biological materials (e.g., sulfated polysaccharides and cyclodextrins). It will be shown that these adsorbents can play a relevant role in the viruses removal where water and air purification mostly occurring via electrostatic interactions. However, a clear systematic vision of the correlation between the surface potential and the adsorption capacity of the different filters is still lacking and should be provided to achieve a better comprehension of the global phenomenon. The rationalization of the adsorption capacity may be achieved through a proper physico-chemical characterization of new adsorbents, including molecular modeling and simulations, also considering the adsorption of virus-like particles on their surface. As a most timely perspective, the results on this review present potential solutions to investigate coronaviruses and specifically SARS-CoV-2, responsible of the COVID-19 pandemic, whose spread can be limited by the efficient disinfection and purification of closed-spaces air and urban waters.

Metal- and metal/oxide-based engineered nanoparticles and nanostructures: a review on the applications, nanotoxicological effects, and risk control strategies

The production and demand of nanoparticles in the manufacturing sector and personal care products, release a large number of engineered nanoparticles (ENPs) into the atmosphere, aquatic ecosystems, and terrestrial environments. The intentional or involuntary incorporation of ENPs into the environment is carried out through different processes. The ENPs are combined with other compounds and release into the atmosphere, settling on the ground due to the water cycle or other atmospheric phenomena. In the case of aquatic ecosystems, the ENPs undergo hetero-aggregation and sedimentation, reaching different living organisms and flora, as well as groundwater. Accordingly, the high mobility of ENPs in diverse ecosystems is strongly related to physical, chemical, and biological processes. Recent studies have been focused on the toxicological effects of a wide variety of ENPs using different validated biological models. This literature review emphasizes the study of toxicological effects related to using the most common ENPs, specifically metal and metal/oxides-based nanoparticles, addressing different synthesis methodologies, applications, and toxicological evaluations. The results suggest negative impacts on biological models, such as oxidative stress, metabolic and locomotive toxicity, DNA replication dysfunction, and bioaccumulation. Finally, it was consulted the protocols for the control of risks, following the assessment and management process, as well as the classification system for technological alternatives and risk management measures of ENPs, which are useful for the transfer of technology and nanoparticles commercialization.

Heterogeneous Fenton catalysts: A review of recent advances

Heterogeneous Fenton catalysts are emerging as excellent materials for applications related to water purification. In this review, recent trends in the synthesis and application of heterogeneous Fenton catalysts for the abatement of organic pollutants and disinfection of microorganisms are discussed. It is noted that as the complexity of cell wall increases, the resistance level towards various disinfectants increases and it requires either harsh conditions or longer exposure time for the complete disinfection. In case of viruses, enveloped viruses (e.g. SARS-CoV-2) are found to be more susceptible to disinfectants than the non-enveloped viruses. The introduction of plasmonic materials with the Fenton catalysts broadens the visible light absorption efficiency of the hybrid material, and incorporation of semiconductor material improves the rate of regeneration of Fe(II) from Fe(III). A special emphasis is given to the use of Fenton catalysts for antibacterial applications. Composite materials of magnetite and ferrites remain a champion in this area because of their easy separation and reuse, owing to their magnetic properties. Iron minerals supported on clay materials, perovskites, carbon materials, zeolites and metal-organic frameworks (MOFs) dramatically increase the catalytic degradation rate of contaminants by providing high surface area, good mechanical stability, and improved electron transfer. Moreover, insights to the zero-valent iron and its capacity to remove a wide range of organic pollutants, heavy metals and bacterial contamination are also discussed. Real world applications and the role of natural organic matter are summarised. Parameter optimisation (e.g. light source, dosage of catalyst, concentration of H2O2 etc.), sustainable models for the reusability or recyclability of the catalyst and the theoretical understanding and mechanistic aspects of the photo-Fenton process are also explained. Additionally, this review summarises the opportunities and future directions of research in the heterogeneous Fenton catalysis.

Agglomeration of Viruses by Cationic Lignin Particles for Facilitated Water Purification

Virus contamination of water is a threat to human health in many countries. Current solutions for inactivation of viruses mainly rely on environmentally burdensome chemical oxidation or energy-intensive ultraviolet irradiation, which may create toxic secondary products. Here, we show that renewable plant biomass-sourced colloidal lignin particles (CLPs) can be used as agglomeration agents to facilitate removal of viruses from water. We used dynamic light scattering (DLS), electrophoretic mobility shift assay (EMSA), atomic force microscopy and transmission electron microscopy (AFM, TEM), and UV spectrophotometry to quantify and visualize adherence of cowpea chlorotic mottle viruses (CCMVs) on CLPs. Our results show that CCMVs form agglomerated complexes with CLPs that, unlike pristine virus particles, can be easily removed from water either by filtration or centrifugation. Additionally, cationic particles formed by adsorption of quaternary amine-modified softwood kraft lignin on the CLPs were also evaluated to improve the binding interactions with these anionic viruses. We foresee that due to their moderate production cost, and high availability of lignin as a side-stream from biorefineries, CLPs could be an alternative water pretreatment material in a large variety of systems such as filters, packed columns, or flocculants.