Nanoparticles demonstrate new and unexpected mechanism of coronavirus disinfection

Amazing stuff! I bet it applies not only to coronavirus!

"... One promising approach relies on the use of nanoparticles, with several metal and metal oxide nanoparticles showing anti-viral activity against SARS-CoV-2, the virus that causes COVID-19. With this in mind, researchers ... investigated the effect of such nanoparticles on two different virus types.

Aiming to elucidate the nanoparticles’ mode of action, they discovered a previously unknown antiviral mechanism ..."

"... It should also be easy to design cost-effective filters to purify contaminated air and water,” ...

Now, researchers ... have studied the outcome when certain types of mineral nanoparticles come into contact with a coronavirus, and they discovered a mode of action that has not been proposed before. ...

Coronaviruses belong to a type of virus that has an outer envelope, a lipid membrane. It turned out that nanoparticles of sand minerals such as titanium oxide bind very strongly to phospholipids in this membrane. This damages the membrane and leads to the release of viral genetic material, thereby making the virus less able to infect cells. ..."

From the abstract:

"The recent COVID-19 pandemic has set a strong quest for advanced understanding of possible tracks in abating and eliminating viral infections. In the view that several families of “pristine” small oxide nanoparticles (NPs) have demonstrated viricidal activity against SARS-CoV-2, we studied the effect of two NPs, with presumably different reactivity, on two viruses aiming to evaluate two “primary suspect” routes of their antiviral activity, either specific blocking of surface proteins or causing membrane disruption.

The chosen NPs were non-photoactive 3.5 nm triethanolamine terminated (surface capped) titania TiO2 NPs (TATT) and ultrasmall (1.1 nm) silicotungstate polyoxometalate (POM) NPs. The former were expected to both, interact with viral surface proteins as well as strongly complex with phosphate groups whereas the latter was not expected to form surface complexes.

We demonstrated that expectedly, POM NPs up to 1.25 mM (4.5 mg l−1) had no significant antiviral activity towards neither of the used viruses, an enveloped transmissible gastroenteritis virus (TGEV) belonging to coronaviruses and non-enveloped encelomyocarditis virus (EMCV).

At the same time, TATT NPs exhibited statistically significant (p < 0.05) antiviral activity against TGEV starting from 0.125 mM (12 μg ml−1). However, no antiviral activity of TATT against non-enveloped EMCV was detected. The observation that TATT NPs showed activity only against enveloped viruses and at relatively high concentrations suggests that the effect could be related with complexation with phospholipids. Possible chemical mechanism of viral membrane disruption was investigated by a variable temperature NMR study of NP complexation with model organic phosphate molecules, proving TATT to strongly interact with them and POM remain unreacted. Viral membrane disruption by TATT NPs was additionally confirmed by demonstrating RNA leakage from TGEV upon contact with those NPs. Therefore, our study proved a new mechanism of antiviral action of titania NPs in the dark which involved membrane disruption proceeding via direct surface complexation."

Nanoparticles demonstrate new and unexpected mechanism of coronavirus disinfection – Physics World

Nanoparticles damage coronavirus in an unexpected way, paving the way for new disinfection technology (original news release) "A new way to neutralise the coronavirus and other membrane-surrounded viruses has been discovered by researchers from the Swedish University of Agricultural Sciences and the University of Tartu. Certain mineral nanoparticles were found to damage the membrane of the virus, making it less able to enter human cells. The mode of action that is demonstrated has not been discussed in previous research. The technology works at room temperature and also in the dark, offering a range of benefits for disinfecting surfaces, air and water."

Molecular mechanisms behind the anti corona virus activity of small metal oxide nanoparticles (open access)

Fig. 8 Proposed schematics of the interaction between enveloped virus and TATT TiO2/TATT/TATT titanate nanoparticles (grey color indicates phospholipids, yellow and brown indicate different kinds of membrane proteins).

Far-UVC light can virtually eliminate airborne virus in an occupied room, study shows

Good news!

"Far-UVC light is a promising new technology for reducing airborne virus levels in occupied indoor spaces, but its effectiveness has not been evaluated in real-life scenarios. ..."

"... A study ... shows that far-UVC light inactivated nearly all (>99%) of an airborne virus in an occupied work environment, showing that the technology can work as well in a real-life scenario as in the laboratory. ...

Over the past few years, ... team has been developing far-UVC light, which has a shorter wavelength (222-nm) than conventional germicidal UVC light and cannot penetrate or damage living skin or eyes. Laboratory tests at Columbia and other centers have demonstrated that far-UVC quickly and efficiently inactivates airborne pathogens in both small and room-sized test chambers. ..."

From the abstract:

"An emerging intervention for control of airborne-mediated pandemics and epidemics is whole-room far-UVC (200–235 nm). Laboratory studies have shown that 222-nm light inactivates airborne pathogens, potentially without harm to exposed occupants. While encouraging results have been reported in benchtop studies and in room-sized bioaerosol chambers, there is a need for quantitative studies of airborne pathogen reduction in occupied rooms. We quantified far-UVC mediated reduction of aerosolized murine norovirus (MNV) in an occupied mouse-cage cleaning room within an animal-care facility. Benchtop studies suggest that MNV is a conservative surrogate for airborne viruses such as influenza and coronavirus. Using four 222-nm fixtures installed in the ceiling, and staying well within current recommended regulatory limits, far-UVC reduced airborne infectious MNV by 99.8% (95% CI: 98.2–99.9%). Similar to previous room-sized bioaerosol chamber studies on far-UVC efficacy, these results suggest that aerosolized virus susceptibility is significantly higher in room-scale tests than in bench-scale laboratory studies. That said, as opposed to controlled laboratory studies, uncertainties in this study related to airflow patterns, virus residence time, and dose to the collected virus introduce uncertainty into the inactivation estimates. This study is the first to directly demonstrate far-UVC anti-microbial efficacy against airborne pathogens in an occupied indoor location."

Far-UVC light can virtually eliminate airborne virus in an occupied room, study shows

Far-UVC Light Can Virtually Eliminate Airborne Virus in an Occupied Room (original news release)

222 nm far-UVC light markedly reduces the level of infectious airborne virus in an occupied room (open access)

Irradiation with low temperature plasma can protect hydroponic crops from pathogens

Good news! This seems to be a very clever approach!

"... For instance, the nutrient solution that is used to feed the plants can easily become contaminated with pathogens like E. coli. To prevent this from happening, growers can use chemicals or simply replace the contaminated solution — but this is wasteful and impractical. In the new study, researchers turned to a surprising ally to help disinfect the crops: plasma. ...

For their research, the team created low-temperature plasma, using a conventional plasma generator.

... Essentially, the methods target an amino acid called tryptophan commonly used in fertilizers. Tryptophan is very useful in plant development and is regularly used in fertilizers to enhance plant growth and stress resistance. It’s also used as a precursor in the production of natural compounds with antimicrobial properties, offering a sustainable approach to managing plant health and yield.

When the amino acid is irradiated, the plasma electrons generate unstable oxygen particles. These go on to produce unstable tryptophan particles. The plants can still use these particles, but the pathogens can’t. Essentially, this starves E. coli while not affecting the plants ..."

"A group led by researchers ... has developed a disinfection technology that uses low-temperature plasma generated by electricity to cultivate environmentally friendly hydroponically grown crops. This innovative technology sterilizes the crops, promoting plant growth without the use of chemical fertilizers. ..."

From the highlights and abstract:

"Highlights

• Irradiation of L-tryptophan (L-Trp) solutions with electrically neutral atomic oxygen produces immediate bactericidal activity.

• Kynurenine and N’-formylkynurenine were identified as irradiation products in the solution.

• Tryptophan radicals (Trp•) are precursors of the oxygen radical irradiation of the solution.

• The bactericidal effect is mediated by central carbon metabolism via enzyme deactivation in E. coli.

Abstract

Organic fertilizers are useful in hydroponic agriculture to bring about a sustainable society with minimal pollution. Irradiation of l-tryptophan (l-Trp) solutions with electrically neutral atomic oxygen produces immediate bactericidal activity. After oxygen radical irradiation of an l-Trp-containing Escherichia coli suspension at pH 6.3 for 5 min, a colony-forming unit assay showed a 6-log reduction in the number of surviving E. coli. Kynurenine and N’-formylkynurenine were identified as irradiation products in the solution using liquid chromatography–mass spectroscopy and nuclear magnetic resonance spectroscopy. Tryptophan radicals (Trp•) are precursors of kynurenine and N’-formylkynurenine and are detected using spin-trap electron spin resonance. The bactericidal effect is mediated by central carbon metabolism via enzyme deactivation in E. coli. Enzymatic deactivation via the oxygen radical irradiation of a solution containing the amino acid l-Trp eventually resulted in bacterial death."

Plasma can protect hydroponic crops from pathogens Cutting edge agriculture just got a bit better.

Low-Temperature Plasma used to remove E. coli from hydroponically grown crops

Oxygen radical irradiation transforms an organic fertilizer l-tryptophan into an environment and human-friendly bactericide

Graphical abstract

Millimeter wave radiation can kill COVID-19 and polio virus, Israeli study shows

Interesting study, but is this method practical to use in every day life the study won't say!

"... It does not appear that the technology can currently target the virus in the human body, “but it can be very useful for rooms, equipment and all forms of surfaces that need to be clear from any virus and coronavirus specifically,” ...

the big advantage offered by millimeter waves is that they can disinfect a surface very fast. ...

The radiation is also very gentle on the surfaces, neither heating them nor affecting them, and therefore can be used on delicate surfaces such as electronic equipment.

The scientists also tried the same technology with the poliovirus and obtained similar results. ...

For the future, the researchers are focusing on applying the technique to disinfect water. ..."

From the abstract:

"... However, their efficiency in object decontamination for viruses has not been tested yet. Here we report the high efficiency of 95 GHz waves in killing both coronavirus 229E and poliovirus. An exposure of 2 s to 95 GHz waves reduced the titer of these viruses by 99.98% and 99.375%, respectively, and formed holes in the envelope of 229E virions as detected by scanning electron microscopy (SEM) analysis. ..."

Special radiation can kill COVID-19 and polio virus, Israeli study shows - The Jerusalem Post Millimeter waves can be used as an effective tool to kill over 99% of the pathogens on different surfaces in two seconds, research by Ariel University scholars indicates.

Corona and polio viruses are sensitive to short pulses of W-band gyrotron radiation (open access)