Engineering nanosilver as an antibacterial, biosensor and bioimaging material

The capacity of nanosilver (Ag nanoparticles) to destroy infectious micro-organisms makes it one of the most powerful antimicrobial agents, an attractive feature against ‘super-bugs’ resistant to antibiotics. Furthermore, its plasmonic properties facilitate its employment as a biosensor or bioimaging agent. Here, the interaction of nanosilver with biological systems including bacteria and mammalian cells is reviewed. The toxicity of nanosilver is discussed focusing on Ag+ ion release in liquid solutions. Biomedical applications of nanosilver are also presented capitalizing on its antimicrobial and plasmonic properties and summarizing its advantages, limitations and challenges. Though a lot needs to be learned about the toxicity of nanosilver, enough is known to safely use it in a spectrum of applications with minimal impact to the environment and human health.

► The toxicity of small nanosilver (<10 nm) is traced to its ion leaching.
► The toxicity of larger nanosilver is traced increasingly to contact with its surface.
► Nanosilver exhibits antimicrobial activity useful against antibiotic-resistant superbugs.
► Hermetic coatings on nanosilver facilitate its use in bioimaging and biosensors.
► Nanosilver with closely controlled size can be made by scalable technology.