The theory would lead us to believe that maximizing the surface area of metallic silver in contact with pathogens would increase the colloid's ability to kill such pathogens. Silver colloids are available with widely varying amounts of particle surface area. Because this is considered an important metric for comparison, the particle surface area is reported in the Commercial Product Reports section of this site. Generally, products that contain a high percentage of silver in the form of silver ions will have a very low particle surface area, while products that have a high percentage of silver in the form of particles will have a higher particle surface area. The highest particle surface area will be found in products having the highest particle concentration and the smallest sized particles. For more details on particle surface area see: About Particle Size