In a new study, scientists from the University of Jyväskylä and the University of Eastern Finland evaluated the antiviral efficacy of various wood types, including coniferous and deciduous trees, against coronaviruses and enteroviruses.
Shroff et al. revealed excellent antiviral activity manifesting already within 10 to 15 min in Scots pine and Norway spruce, particularly against enveloped viruses; in contrast, other hardwoods displayed varied efficacy, with oak showing effectiveness against the enterovirus. Image credit: Shroff et al., doi: 10.1021/acsami.4c02156.
Since prehistoric times, wood has played an essential role in tools, utilities, and built environment.
The 20th century witnessed excessive exploitation of wood that together with rapid industrial advancements provided several alternatives like plastics and metals in interior surfacing and utilities in our built environment.
Recent trends, underlined by sustainability concerns and appreciation for wood’s unique aesthetic and haptic properties are reclaiming the use of wood in many daily uses.
Parallel to these material trends, the 21st century is marked by emerging health challenges, notably viral outbreaks, such as SARS and COVID-19.
Transmission mechanisms for these viruses include not only direct human-to-human contact but also interactions with contaminated surfaces.
Viruses do not replicate outside their host cells; however, they are able to persist for a long period of time on different surfaces as fomites.
While enveloped viruses, such as coronaviruses, exhibit quite short surface persistence up to 5 days, nonenveloped viruses on the other hand, shielded by robust protein capsids, can endure for weeks, often resisting standard disinfection techniques. This is due to the presence of a strong protein capsid which is difficult to break down with disinfectants.
While disinfectants remain the primary strategy for neutralizing surface pathogens, their efficacy is limited and their continuous use poses environmental, health, and material degradation concerns.
Previous studies have shown that wood has antibacterial and antifungal properties, making it an ideal material for cutting boards.
However, wood’s ability to inactivate viruses has yet to be explored, which is what University of Jyväskylä researcher Varpu Marjomäki and colleagues set out to study.
They looked at how long enveloped and nonenveloped viruses remained infectious on the surface of six types of wood: Scots pine, silver birch, gray alder, eucalyptus, pedunculate oak and Norway spruce.
To determine viral activity, they flushed a wood sample’s surface with a liquid solution at different time points and then placed that solution in a Petri dish that contained cultured cells.
After incubating the cells with the solution, they measured the number (if any) infected with the virus.
Their results from demonstrations with an enveloped coronavirus showed that pine, spruce, birch and alder need one hour to completely reduce the virus’ ability to infect cells, with eucalyptus and oak needing two hours.
Pine had the fastest onset of antiviral activity, beginning after five minutes. Spruce came in second, showing a sharp drop in infectivity after 10 minutes.
For a nonenveloped enterovirus, the researchers found that incubation on oak and spruce surfaces resulted in a loss of infectivity within about an hour, with oak having an onset time of 7.5 minutes and spruce after 60 minutes.
Pine, birch and eucalyptus reduced the virus’ infectivity after four hours, and alder showed no antiviral effect.
Based on their data, the scientists concluded that the chemical composition of a wood’s surface is primarily responsible for its antiviral functionality.
“While determining the exact chemical mechanisms responsible for viral inactivation will require further study, our findings point to wood as a promising potential candidate for sustainable, natural antiviral materials,” they concluded.
Their paper appears in the journal ACS Applied Materials & Interfaces.
_____
Sailee Shroff et al. 2024. Tree Species-Dependent Inactivation of Coronaviruses and Enteroviruses on Solid Wood Surfaces. ACS Appl. Mater. Interfaces 16 (23): 29621-29633; doi: 10.1021/acsami.4c02156
Source : Breaking Science News