Surface-enhanced fluorescence from metal sculptured thin films with application to biosensing in water

Abstract

Surface-enhanced fluorescence from porous, metallic sculptured thin films ͑STFs͒ was demonstrated for sensing of bacteria in water. Enhancement factors larger than 15 were observed using STFs made of silver, aluminum, gold, and copper with respect to their dense film counterparts. The STFs used are assemblies of tilted, shaped, parallel nanowires prepared with several variants of the oblique-angle-deposition technique. Comparison between the different films indicates that the enhancement factor is higher when the tilt is either small ͑Ͻ30 deg͒ or large ͑Ͼ80 deg͒; thus, the enhancement is higher when only a single resonance in the nanowires is excited.

Sensitivity‐enhancement methods for surface plasmon sensors

“…Surface-enhanced fluorescence from porous, metallic sculptured thin films (STFs) was demonstrated for sensing of bacteria in water by Abdulhalim et al [163] Enhancement factors larger than 15 were observed using STFs made of silver, aluminum, gold, and copper with respect to their dense-film counterparts. The STFs used are assemblies of tilted, shaped, parallel nanowires prepared with several variants of the oblique-angle-deposition technique (OAD).…”

“…The STFs used are assemblies of tilted, shaped, parallel nanowires prepared with several variants of the oblique-angle-deposition technique (OAD). Abdulhalim et al [163] examined the effect of the substrate material, constituent rods material, porosity, and the rods tilt angle on the enhancement factor of SEF. Enhancement of SEF from porous, metallic STFs was applied to biosensing in water.…”

Tunable Nanowrinkles on Shape Memory Polymer Sheets

“…0.5-to 5-fold increase of the fluorescence intensity can be achieved. [31,32] Here, we demonstrate that our continuous gold wrinkled substrate is useful for MEF as well. Figures 3c and d (top) show fluorescence images along with the corresponding intensity profiles of dyes, dissolved in polymer solution and then spin-coated on either a bare glass plate or uniaxial gold wrinkles.…”

“…[34] Compared with results from other continuous gold film nanostructures, a 7-fold enhancement is a significant achievement. [31,32] If the geometry of wrinkles is optimized, the critical spacing between the fluorophore and substrate controlled, and the density of intense hotspots increased, an average fluorescence intensity increase by at least one order of magnitude can be achieved. One potential MEF application is to improve the sensitivity of DNA and protein microarrays, in which high density probes with spot sizes from 10 to 500 mm are immobilized on substrates with areas of several square centimeters.…”

Arbitrarily shaped Si nanostructures by glancing angle ion beam sputter deposition

“…The simplicity of this deposition technique with its ability to ''tailor'' the morphology of nanostructured thin films of various materials makes this deposition approach an ideal candidate for the fabrication of functional thin films whose functionality is based on the morphological dependence of various physical properties. Applications of glancing angle deposited thin films include square spiral photonic crystals [10][11][12], polarization filters [13], polarized light emitters [14], broadband antireflection coatings [15,16], narrow bandpass optical filters [17], high-speed humidity sensors [18], high sensitivity surface enhanced Raman spectroscopy [19][20][21] or surface enhanced fluorescence [22] substrates, and biomimetization [23], to name only a few.…”