In this article, discover how colloidal silver has been used for centuries for its various health benefits

The potential adverse effects of nanoparticles on humans and the environment currently receive a lot of attention both in academia and with regulators. 

A lot of the discussion is centered on the asserted assumption that nanoparticles are something fundamentally “new”andthus cannot be compared to conventional chemicals or bulk materials. Nanosilver is one of the nanomaterials that is under the most scrutiny today and its release and effects are studied widely. Although changes in nomenclature over the decades have created confusion among scientists and policy makers, it is undeniable that products containing nanoscale silver particles have been commercially available for over 100 years and were used in applications as diverse as pigments, photographics, wound treatment, conductive/antistatic composites, catalysts, and as a biocide. With this long and diverse history of use it is clear that an extraordinary amount of research into the chemistry of nanoscale silver has been conducted over the past 120 years; it should be noted that most research, until very recently, did not use “nano” nomenclature. In this analysis we critically examine with respect to nanosilver three important assertions often made when discussing risk assessment of silver nanoparticles:  

  1. Nanosilver is new and exhibits unique physical and chemical properties compared to “conventional” silver (e.g., macroscale “bulk” silver). 
  1. Nanosilver has been used for only a few years and the environment and humans have never been exposed to nanosilver before.  
  1. Existing risk assessments of silver have been based on a data set derived from conventional silver materials, so they do not apply to nanosilver. 


Antimicrobial biocides are commonly used to prevent the growth of bacteria on surfaces and within materials and are typically added in small quantities to many applications to make it more difficult for bacteria to grow on the treated object. Biocidal functionality can be achieved by employing either organic or inorganic active agents. Compounds such as quaternary ammonium and chlorinated phenols are examples of two widely used organic chemical biocidal agents. Inorganic active agents are generally based on metals such as silver and copper. Silver has found a growing presence in many applications due to a desire to shift away from organic chemical agents toward additives, which can be used in much lower concentrations in a wider variety of products including applications such as plastics where high temperature processing is not feasible for organic compounds. Examples of applications are bacteriostatic water filters for household use or swimming pool algicides. 

To meet the diversity of application types, many different forms of silver compounds have been developed to service this market. Whereas biocidal action derives from interaction of silver ions with bacteria, silver additives are differentiated primarily by the way the silver ions are stored in the product. Common silver products range from additives that store and release discrete silver ions held within a ceramic (e.g., zeolite) or glass matrix, through to products that store silver ions as silver salts (e.g., silver chloride) or elemental silver (e.g., nanoscale silver metal).