title: Electron beam lithography designed silver nano-disks used as label free nano-biosensors based on localized surface plasmon resonance.
abstract: We present a label-free, optical nano-biosensor based on the Localized Surface Plasmon Resonance (LSPR) that is observed at the metal-dielectric interface of silver nano-disk arrays located periodically on a sapphire substrate by Electron-Beam Lithography (EBL). The nano-disk array was designed by finite-difference and time-domain (FDTD) algorithm-based simulations. Refractive index sensitivity was calculated experimentally as 221-354 nm/RIU for different sized arrays. The sensing mechanism was first tested with a biotin-avidin pair, and then a preliminary trial for sensing heat-killed Escherichia coli (E. coli) O157:H7 bacteria was done. Although the study is at an early stage, the results indicate that such a plasmonic structure can be applied to bio-sensing applications and then extended to the detection of specific bacteria species as a fast and low cost alternative.
authors.affiliation: Nanotechnology Research Center, Bilkent University, 06800 Bilkent, Turkey. nyilmaz@ee.bilkent.edu.tr
authors.forename: Neval A
authors.initials: NA
authors.lastname: Cinel
authors.forename: Serkan
authors.initials: S
authors.lastname: Bütün
authors.forename: Ekmel
authors.initials: E
authors.lastname: Özbay
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D017076:Computer-Aided Design; D004583:Electrons; D004867:Equipment Design; D019544:Equipment Failure Analysis; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D012031:Refractometry / Q000295:instrumentation*; D012834:Silver / Q000737:chemistry* / Q000528:radiation effects; D013194:Staining and Labeling; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D012834:Silver