Nano-particles/ nano-composite polymers:
From ancient time, silver (Ag) and copper (Cu) are renowned for their anti-microbial efficiency. Ag and Cu nano-particles have attracted attentions for their applications in numerous fields. In past few years, copper being heavy metal, having known its side effects on human being and other living organisms, copper's direct use as preservative has been controlled in many industries.
However, silver nano-particles have unparalleled advantages due to its broad antimicrobial spectrum, high stability, low human toxicity.
Mechanism of anti-microbial effect of silver is not completely understood. Three mechanisms are proposed for silver nano-particles are, (i) gradual release of silver ions, followed by disruption of ATP production and DNA replication, (ii) direct damage to cell membrane by silver nano-particles and (iii) silver nano-particles and silver ion generation of reactive oxygen species.
Figure 1 explains possible mechanisms of silver to kill microbes.