LAUSR

Sovereign Silver and Argentyn 23 are the brand names of the Bio-Active Silver Hydrosol manufactured by Natural Immunogenics Corp (NIC). The products contain a mixture of positively charged silver ions and silver nanoparticles. In a 2020 publication by Kumar et al., 1 Sovereign Silver and Argentyn 23 were included as part of a “comparative evaluation of commercial colloidal silver products”. This publication concluded that there were no silver nanoparticles (AgNPs) present neither in the Sovereign Silver nor the Argentyn 23 products. This letter aims at providing a perspective omitted in the aforementioned publication and supporting the manufacturer’s marketing message as it relates to the presence of silver nanoparticles in its products, by providing detailed characterization using TEM and AFM. There are numerous tools that can potentially be used for characterizing nanoparticles. 2 While it is best to have multiple, orthogonal characterization techniques, there is an international consensus for transmission electron microscopy (TEM) being the “gold standard” technique for nanoparticle characterization. For example, the European Food Safety Authority (EFSA) requires two techniques to characterize the size and size distribution of nanomaterials in foods, one of which must be TEM and one of which the applicant may choose. 3 1 representative TEM images of Sovereign Silver and Argentyn 23 products, which clearly demonstrate discrete and narrowly distributed silver nanoparticles. A from nine batches of Argentyn 23 no less than five images per batch, A