What are the main findings?

• Colloidal form of silver is biologically more reactive than the ionic form.
• Silver nanoparticles (AgNPs) can strongly bind to the spikes of the SARS-CoV-2 virus and prevent host cell attachment.
• Anti-viral activity of the AgNPs mainly depends on their size and structural features.

What is the implication of the main finding?

• AgNPs could be used to tackle the variants of SARS-CoV-2 virus effectively.
• Increased toxicity of AgNPs at the higher concentrations is a point of concern to be addressed.

COVID-19 is an epizootic and life-threatening outbreak affecting millions of people globally. Coronavirus variants have emerged in different locations since their origin. Silver and its compounds, including silver nanoparticles (AgNPs), have been used in the medical field for a long period, especially in surgical treatments. The anti-microbial and anti-viral properties of silver are well documented. These properties depend on the size of the particles, concentration, precursor, method of preparation, and the presence of other benefiting compounds. Several experiments were conducted by researchers worldwide to prove the anti-bacterial and anti-viral properties of silver (Ag) and AgNPs, emphasizing that silver can be introduced to multiple organs in the human body and exhibit the expected antiviral characteristics. In this review article, use of silver nanoparticles to fight the COVID-19 pandemic according with the current information is discussed. The mechanisms involving antiviral activity and toxicity are discussed in detail. This article concludes that strong binding of AgNPs with SARS-CoV-2 virus prevents binding with the host cell, leading to the death of the virus. However, increased cytotoxic effect of the silver compounds at higher concentrations is a matter of concern.