Plasmonic biosensors with biocompatible nanosilver

The plasmonic properties of noble metal nanoparticles facilitate their use in novel in-vivo bio-applications such as targeted drug delivery and cancer cell therapy. Nanosilver is best suited for such applications as it has the lowest plasmonic losses among all such materials in the UVvisible spectrum. Its toxicity, however, can destroy the surrounding healthy tissue and thus, hinders its safe employment. Here, that toxicity against a model biological system (Escherichia coli) is “cured” by coating nanosilver hermetically with a thin SiO2 layer by a scalable flame aerosol method without reducing its plasmonic performance. This creates the opportunity to safely use powerful nanosilver for intracellular bio-applications. The label-free biosensing and surface bio-functionalization of these ready-to-use, non-toxic (benign) nanosilver particles is presented here by measuring the adsorption of bovine serum albumin (BSA) in a model sensing experiment. Furthermore, the silica coating around nanosilver prevents its agglomeration or flocculation and thus, enhances its biosensitivity.