(746b) Plasmonic Biosensors with Biocompatible Nanosilver

Sotiriou, G. A., Particle Technology Laboratory, ETH Zurich
Sannomiya, T., Laboratory of Biosensors and Biolelectronics, ETH Zurich
Teleki, A., Particle Technology Laboratory, ETH Zurich
Vörös, J., Laboratory of Biosensors and Biolelectronics, ETH Zurich
Pratsinis, S. E., Swiss Federal Institute of Technology, Particle Technology Laboratory, ETH Zurich

Noble metal nanoparticles and their unique plasmonic properties allow them to be used as agents for novel in-vivo bio-applications, such as targeted drug delivery and cancer cell therapy [1]. Nanosilver is the optimum such material because of its lowest losses of the plasmonic properties in the visible spectrum. The toxic nanosilver surface [2], however, can destroy the surrounding healthy tissue and thus, challenges its safe employment [3]. Therefore, “curing” nanosilver’s toxicity would open up its use for such innovative biological applications. Here, nanosilver particles are hermetically coated with a thin SiO2 layer using a scalable aerosol method [4]. Uncoated or partially coated nanosilver exhibits substantial toxicity against E. coli bacteria, while encapsulating it prevents this. The performance of these ready-to-use, biocompatible nanosilver particles as biosensors is demonstrated by measuring the adsorption of bovine serum albumin (BSA) in a model sensing experiment. The silica coating prevents nanosilver agglomeration and thus, apart from the limited toxicity, enhances the biosensitivity.

[1] Sotiriou, G. A., Hirt, A. M., Lozach, P. Y., Teleki, A., Krumeich, F. & Pratsinis, S. E. Hybrid, Silica-Coated, Janus-like Plasmonic-Magnetic Nanoparticles. Chem. Mater. 23, 1985-1992 (2011).

[2] Sotiriou, G. A. & Pratsinis, S. E. Antibacterial activity of nanosilver ions and particles. Environ. Sci. Technol. 44, 5649-5654 (2010).

[3] Sotiriou, G. A., Sannomiya, T., Teleki, A., Krumeich, F., Vörös, J. & Pratsinis, S. E. Non-Toxic Dry-Coated Nanosilver for Plasmonic Biosensors. Adv. Funct. Mater. 20, 4250-4257 (2010).