Research

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19 pages, 7460 KiB

Open AccessArticle

A Comparative Study of the Antiviral Properties of Thermally Sprayed Coatings against Human Coronavirus HCoV-229E

by Elnaz Alebrahim, Hediyeh Khatibnezhad, Morvarid Mohammadian Bajgiran, Magan Solomon, Chen Liang, Selena M. Sagan, Rogerio S. Lima, Jörg Oberste Berghaus, Maniya Aghasibeig and Christian Moreau

Catalysts 2023, 13(7), 1141; https://0-doi-org.brum.beds.ac.uk/10.3390/catal13071141 - 22 Jul 2023

Cited by 2 | Viewed by 1147

Abstract

For decades, novel viral strains of respiratory tract infections have caused human pandemics and initiated widespread illnesses. The recent coronavirus disease 2019 (COVID-19) outbreak caused by the SARS-CoV-2 virus has raised an urgent need to develop novel antiviral coatings as one of the [...] Read more.

For decades, novel viral strains of respiratory tract infections have caused human pandemics and initiated widespread illnesses. The recent coronavirus disease 2019 (COVID-19) outbreak caused by the SARS-CoV-2 virus has raised an urgent need to develop novel antiviral coatings as one of the potential solutions to mitigate the transmission of viral pathogens. Titanium dioxide is considered an excellent candidate for viral disinfection under light irradiation, with the potential to be activated under visible light for indoor applications. This research assessed the antiviral performance of thermally sprayed TiO₂ coatings under UVA and ambient light. We also report the antiviral performance of TiO₂ composites with other oxides, such as Cu₂O and Al₂O₃, produced by suspension plasma spray, atmospheric plasma spray, and suspension high-velocity oxygen fuel techniques. To evaluate the antiviral performance of the above coatings in a containment level-2 laboratory, a human common cold coronavirus, HCoV-229E, was initially used as a relevant surrogate for SARS-CoV-2. Coatings were also analyzed using SEM and XRD and were classified based on their surface roughness, porosity, and phase composition. Collectively, the thermally sprayed coatings showed comparable or slightly better antiviral activity compared to copper. The most significant level of activity observed was approximately 20% to 50% higher than that of a pure copper plate. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials for Abatement of Microorganisms)

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15 pages, 2665 KiB

Open AccessArticle

Comparison of Photocatalytic Biocidal Activity of TiO₂, ZnO and Au/ZnO on Escherichia coli and on Aspergillus niger under Light Intensity Close to Real-Life Conditions

by Mohamad Al Hallak, Thomas Verdier, Alexandra Bertron, Kevin Castelló Lux, Ons El Atti, Katia Fajerwerg, Pierre Fau, Julie Hot, Christine Roques and Jean-Denis Bailly

Catalysts 2023, 13(7), 1139; https://0-doi-org.brum.beds.ac.uk/10.3390/catal13071139 - 22 Jul 2023

Cited by 1 | Viewed by 1946

Abstract

Microbial contamination of the surface of building materials and subsequent release of microbial particles into the air can significantly affect indoor air quality. Avoiding the development or, at least, reducing the quantity of microorganisms growing on building materials is a key point to [...] Read more.

Microbial contamination of the surface of building materials and subsequent release of microbial particles into the air can significantly affect indoor air quality. Avoiding the development or, at least, reducing the quantity of microorganisms growing on building materials is a key point to reduce health risks for building occupiers. In that context, the antimicrobial activity of TiO₂, ZnO and Au/ZnO was assessed by measuring log reductions of Escherichia coli and Aspergillus niger populations both in the dark and under a light intensity close to real-life conditions. The bactericidal activities (≥2.3 log reduction) of tested products were stronger than their fungicidal activities (≤1.4 log reduction) after 2 h of contact. Different parameters including concentration of photocatalyst, intensity of light (dark vs. 5 W/m² UV-A), and duration of contact between photocatalyst and microbial cells and spores were investigated. Results of this study confirmed bactericidal activities of TiO₂, ZnO and AuZnO on E. coli and brought new insight on their fungicidal activity on the spores of A. niger. They also confirmed the greatest antimicrobial efficiency of ZnO compared to TiO₂ and its increased photocatalytic activity when decorated with Au, leading to the highest log reductions detected after 2 h of contact for both tested microorganisms (4 and 1.4 for E. coli and A. niger, respectively). The antimicrobial activity was enhanced by the duration of contact between microorganisms and nanoparticles of the different tested photocatalytic products. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials for Abatement of Microorganisms)

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13 pages, 3438 KiB

Open AccessArticle

Light-Activated Modified Arginine Carbon Dots as Antibacterial Particles

by Selin S. Suner, Mehtap Sahiner, Aynur S. Yilmaz, Ramesh S. Ayyala and Nurettin Sahiner

Catalysts 2022, 12(11), 1376; https://0-doi-org.brum.beds.ac.uk/10.3390/catal12111376 - 07 Nov 2022

Cited by 4 | Viewed by 1911

Abstract

Nitrogen-doped arginine carbon dots (Arg CDs) as light-sensitive antibacterial agents were prepared by using citric acid as the carbon source and arginine amino acid as the nitrogen source via a microwave-assisted synthesis method. Dynamic light scattering (DLS) measurements and TEM images revealed that [...] Read more.

Nitrogen-doped arginine carbon dots (Arg CDs) as light-sensitive antibacterial agents were prepared by using citric acid as the carbon source and arginine amino acid as the nitrogen source via a microwave-assisted synthesis method. Dynamic light scattering (DLS) measurements and TEM images revealed that the Arg CDs were in the 1–10 nm size range with a graphitic structure. To improve their antibacterial capability, the Arg CDs were modified with ethyleneimine (EDA), pentaethylenehexamine (PEHA), and polyethyleneimine (PEI) as different amine sources, and the zeta potential value of +2.8 ± 0.6 mV for Arg CDs was increased to +34.4 ± 4.1 mV for PEI-modified Arg CDs. The fluorescence intensity of the Arg CDs was significantly enhanced after the modification with EDA, and the highest antibacterial effect was observed for the PEI-modified Arg CDs. Furthermore, the photodynamic antibacterial capacity of bare and EDA-modified Arg CDs was determined upon light exposure to show their light-induced antibacterial effects. Photoexcited (315–400 nm, UVA, 300 W), EDA-modified Arg CDs at 5 mg/mL concentration were found to inhibit about 49 ± 7% of pathogenic bacteria, e.g., Escherichia coli, with 5 min of light exposure. Furthermore, the biocompatibilities of the bare and modified Arg CDs were also investigated with blood compatibility tests via hemolysis and blood clotting assays and cytotoxicity analysis on L929 fibroblast cells. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials for Abatement of Microorganisms)

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15 pages, 1805 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Inactivation and Degradation of Influenza A Virus on the Surface of Photoactive Self-Cleaning Cotton Fabric Functionalized with Nanocrystalline TiO₂

by Dmitry Selishchev, Grigory Stepanov, Mariia Sergeeva, Maria Solovyeva, Evgenii Zhuravlev, Andrey Komissarov, Vladimir Richter and Denis Kozlov

Catalysts 2022, 12(11), 1298; https://0-doi-org.brum.beds.ac.uk/10.3390/catal12111298 - 23 Oct 2022

Cited by 3 | Viewed by 1835

Abstract

Chemical modification of cotton-rich fabrics with TiO₂ nanoparticles results in photoactive self-cleaning textiles, which can provide, under UV or solar radiation, complete oxidation of low-molecular compounds, degradation of supramolecular structures, and inactivation of microorganisms due to the photocatalytic effect. In this paper, [...] Read more.

Chemical modification of cotton-rich fabrics with TiO₂ nanoparticles results in photoactive self-cleaning textiles, which can provide, under UV or solar radiation, complete oxidation of low-molecular compounds, degradation of supramolecular structures, and inactivation of microorganisms due to the photocatalytic effect. In this paper, we describe, based on the example of influenza A (H1N1) virus, a photoinduced antiviral effect of cotton fabric functionalized with nanocrystalline TiO₂. Fast inactivation of influenza virus occurs on the irradiated surface of photoactive fabric due to adsorption and photocatalytic degradation. The TiO₂ component in the prepared fabric increases the adsorption effect compared to initial cotton due to a high specific area of TiO₂ nanocrystallites. Long-term irradiation leads to destruction of all virion structures to the point of RNA molecules. In contrast to pristine cotton, no virus RNA is detected using the polymerase chain reaction (PCR) technique after long-term irradiation of photoactive fabric. The results of this study underline the potential of photoactive self-cleaning fabrics for application in air purification systems and personal protective clothes to provide permanent protection of people against harmful chemical and biological pollutants. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials for Abatement of Microorganisms)

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10 pages, 2306 KiB

Open AccessArticle

Surface Inactivation of Human Coronavirus by MACOMA™ UVA-TiO₂ Coupled Photocatalytic Disinfection System

by Timsy Uppal, Sivani Reganti, Ezekiel Martin and Subhash C. Verma

Catalysts 2022, 12(7), 690; https://0-doi-org.brum.beds.ac.uk/10.3390/catal12070690 - 24 Jun 2022

Cited by 3 | Viewed by 2859

Abstract

There is an immense healthcare challenge and financial pressure due to the COVID-19 pandemic caused by a newly identified human coronavirus, SARS-CoV-2. Effective COVID-19 prevention efforts in healthcare, home, and community settings highlight the need for rapid, efficient, and no-contact SARS-CoV-2 inactivation strategies. [...] Read more.

There is an immense healthcare challenge and financial pressure due to the COVID-19 pandemic caused by a newly identified human coronavirus, SARS-CoV-2. Effective COVID-19 prevention efforts in healthcare, home, and community settings highlight the need for rapid, efficient, and no-contact SARS-CoV-2 inactivation strategies. Here, we examined the photocatalytic and virucidal activity of the MACOMA™ TiO₂ photocatalytic film activated by an UVA-LED-12V-367 nm (MA-717836-1) lamp against the HCoV-OC43, a member of the beta coronaviruses family, like SARS-CoV-2, using quantitative RT-qPCR and virus infectivity assays. The UVA radiation-responsive TiO₂ film accelerated virus inactivation (decreased viral titer) compared to the uncoated glass surface when placed at a vertical distance of 1.2 feet (~14 inches) from virus samples for 10, 30, and 60 min. UVA-LED exposure for both 10 and 30 min effectively reduced the viral RNA copies and the infectious virus in samples on TiO₂-coated surfaces compared to the control surfaces. Importantly, a 60 min exposure of samples on the TiO₂ completely eliminated HCoV-OC43. These results confirmed that the MACOMA™ UVA/TiO₂-based disinfection system provides a rapid and complete surface inactivation of tested human coronavirus in a human-safe manner and has great potential for limiting the virus spread in poorly ventilated as well as high-traffic public places. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials for Abatement of Microorganisms)

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13 pages, 2664 KiB

Open AccessArticle

Antimicrobial Activity of Commercial Photocatalytic SaniTise™ Window Glass

by Vambola Kisand, Meeri Visnapuu, Merilin Rosenberg, Dmytro Danilian, Sergei Vlassov, Mati Kook, Sven Lange, Rainer Pärna and Angela Ivask

Catalysts 2022, 12(2), 197; https://0-doi-org.brum.beds.ac.uk/10.3390/catal12020197 - 05 Feb 2022

Cited by 4 | Viewed by 1835

Abstract

Photocatalytic and antibacterial properties of TiO₂-based SaniTise™ glass by Pilkington were studied with an aim to benchmark this first commercial UVA-activated antimicrobial glass and to evaluate its efficacy in indoor-like conditions. For comparison, the antibacterial and photocatalytic activity of self-cleaning BIOCLEAN [...] Read more.

Photocatalytic and antibacterial properties of TiO₂-based SaniTise™ glass by Pilkington were studied with an aim to benchmark this first commercial UVA-activated antimicrobial glass and to evaluate its efficacy in indoor-like conditions. For comparison, the antibacterial and photocatalytic activity of self-cleaning BIOCLEAN^® glass and photocatalytically inactive clear float PLANICLEAR^® control glass were analysed. The presence of an anatase TiO₂ layer was demonstrated on the surface of SaniTise™ and BIOCLEAN^®. Photocatalytic degradation of organic model dye and antibacterial activity against Escherichia coli and Staphylococcus aureus were higher on SaniTise™ than on BIOCLEAN^®. In a liquid antibacterial assay corresponding to ISO 27447 format, 4 h exposure of bacteria to the SaniTise™ surface under UVA resulted in >2.8 log decrease in E. coli and >2.5 log decrease in S. aureus viable cell counts. In experiments with the more application-relevant “dry droplet method”, significantly higher antibacterial activity was observed up to the level where during 4 h at ≤50% RH complete inactivation of bacteria was observed also on PLANICLEAR^® control glass. The latter raises concerns about the real-life relevancy of the standard test conditions and suggests that at low air humidity conditions, shorter exposure periods than suggested by current antimicrobial testing protocols should be targeted by photocatalytically active antibacterial surfaces. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials for Abatement of Microorganisms)

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16 pages, 4466 KiB

Open AccessArticle

A Study on the Characteristic and Antibacterial Activity of Ti₃O_x Thin Films

by Endrika Widyastuti, Fu-Yang Xu, Chen-Tien Chiu, Jhen-Hau Jan, Jue-Liang Hsu and Ying-Chieh Lee

Catalysts 2021, 11(11), 1416; https://0-doi-org.brum.beds.ac.uk/10.3390/catal11111416 - 22 Nov 2021

Cited by 4 | Viewed by 1897

Abstract

A pure Ti target in Ar/O₂ gas mixture was used to synthesize Ti₃O_x thin film on a glass substrate by Reactive High-Power Impulse Magnetron Sputtering (HiPIMS) under different sputtering power (2 and 2.5 kW). The influence of HiPIMS parameters [...] Read more.

A pure Ti target in Ar/O₂ gas mixture was used to synthesize Ti₃O_x thin film on a glass substrate by Reactive High-Power Impulse Magnetron Sputtering (HiPIMS) under different sputtering power (2 and 2.5 kW). The influence of HiPIMS parameters on thin films’ structural, morphological, chemical composition, optical and photocatalytic, and antibacterial properties was investigated. In this study, Ti₃O_x thin films can be synthesized using the HiPIMS method without the post-annealing process. Two co-existence phases (hexagonal Ti₃O and base-centered monoclinic Ti₃O₅ phases) existed on the Ti₃O_x films. It is found that the peak intensity of (006) Ti₃O hexagonal slightly increased as the sputtering power increased from 2 to 2.5 kW. The Ti₃O_x thin-film bandgap values were 3.36 and 3.50 eV for 2 and 2.5 kW, respectively. The Ti₃O_x films deposited at 2.5 kW showed good photocatalytic activity under UV light irradiation, with a higher methylene blue dye degradation rate than TiO₂ thin films. The antibacterial study on Ti₃O_x thin films exhibited a high inhibition percentage against E. coli and S. aureus. This study demonstrates that Ti₃O_x thin films can promote high photocatalytic and antibacterial activity. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials for Abatement of Microorganisms)

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Review

Jump to: Research

25 pages, 3719 KiB

Open AccessReview

Nanoparticle Engineered Photocatalytic Paints: A Roadmap to Self-Sterilizing against the Spread of Communicable Diseases

by Vijay S. Mohite, Milind M. Darade, Rakesh K. Sharma and Shivaji H. Pawar

Catalysts 2022, 12(3), 326; https://0-doi-org.brum.beds.ac.uk/10.3390/catal12030326 - 11 Mar 2022

Cited by 11 | Viewed by 3080

Abstract

Applications of visible-light photocatalytic engineered nanomaterials in the preparation of smart paints are of recent origin. The authors have revealed a great potential of these new paints for self-sterilizing of the surfaces in hospitals and public places simply with visible light exposure and [...] Read more.

Applications of visible-light photocatalytic engineered nanomaterials in the preparation of smart paints are of recent origin. The authors have revealed a great potential of these new paints for self-sterilizing of the surfaces in hospitals and public places simply with visible light exposure and this is reported for the first time in this review. A recent example of a communicable disease such as COVID-19 is considered. With all precautions and preventions taken as suggested by the World Health Organization (WHO), COVID-19 has remained present for a longer time compared to other diseases. It has affected millions of people worldwide and the significant challenge remains of preventing infections due to SARS-CoV-2. The present review is focused on revealing the cause of this widespread disease and suggests a roadmap to control the spread of disease. It is understood that the transmission of SARS-CoV-2 virus takes place through contact surfaces such as doorknobs, packaging and handrails, which may be responsible for many preventable and nosocomial infections. In addition, due to the potent transmissibility of SARS-CoV-2, its ability to survive for longer periods on common touch surfaces is also an important reason for the spread of COVID-19. The existing antimicrobial cleaning technologies used in hospitals are not suitable, viable or economical to keep public places free from such infections. Hence, in this review, an innovative approach of coating surfaces in public places with visible-light photocatalytic nanocomposite paints has been suggested as a roadmap to self-sterilizing against the spread of communicable diseases. The formulations of different nanoparticle engineered photocatalytic paints with their ability to destroy pathogens using visible light, alongwith the field trials are also summarized and reported in this review. The potential suggestions for controlling the spread of communicable diseases are also listed at the end of the review. Full article

(This article belongs to the Special Issue Photocatalytic Nanomaterials for Abatement of Microorganisms)

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