Metal-Enhanced Fluorescence (MEF): Physical characterization of Silver-island films and exploring sample geometries

Abstract

In this study we have analyzed metal-enhanced fluorescence (MEF) effects from different density silver island films (SiFs) and the effects of sample geometry on the observed enhancement of fluorescence (EF). It is shown that silver islands grow exponentially with SiF deposition time (DT<7min), optical density of SiFs almost linearly depends on DT; electrical conductivity is zero. At DT>7 min, silver islands merge, exhibiting a sharp increase in electrical conductivity. It has been shown that the newly proposed SiF-Glass sample geometry exhibits higher EF values than the commonly used in MEF studies SiF-SiF sample geometry. The SiF-Glass geometry demonstrates high sensitivity for surface immunoassays, a growing application of metal-enhanced fluorescence.

Surface‐Enhanced Fluorescence from Fluorophore‐Assembled Monolayers by Using Ag@SiO2 Nanoparticles

“…The closely stacked pattern of nanoparticles may make it difficult for the excitation light to fall onto the fluorophore layer and for the fluorescence signal to emit out through the nanoparticle layer, as was previously reported. [51] The combined effect of the above factors leads to the observed saturated fluorescence. Figure 7 shows the dependence of the enhancement factor on the number of nanoparticle deposition cycles for both kinds of shell thickness.…”

Blind Evaluation of the Microwave-Accelerated Metal-Enhanced Fluorescence Ultrarapid and Sensitive Chlamydia trachomatis Test by Use of Clinical Samples

“…The MAMEF technology was developed by Geddes and colleagues (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27). It combines the significant benefits of low-power microwave acceleration to accelerate biological reactions to completeness within seconds with those of metal-enhanced fluorescence (MEF), whereby the close proximity of silver nanoparticles (plasmon-supporting particles) amplifies the fluorescence or luminescence of labels in the near field, i.e., less than 1 wavelength of light away (28)(29)(30)(31)(32)(33)(34)(35). The resulting technology, MAMEF, allows for combined ultrafast and ultrasensitive detection of DNAs (12)(13)(14)(15)(16)(17)(18)(19)(20), RNAs (36), and proteins (24)(25)(26)(27).…”

5-Color Multiplexed Microwave-Accelerated Metal-Enhanced Fluorescence: Detection and Analysis of Multiple DNA Sequences from within one Sample Well within a Few Seconds

“…In a microwave field, the process of DNA hybridization is significantly accelerated, the time of annealing decreasing from hours to only a few seconds [16].…”

“…The length of DNA fragments employed in the assay was specifically designed to keep the signaling chromophores on a short leash,~6 nm, Fig. 6, from a silver film surface, ensuring the largest enhancement (MEF) of their fluorescence response [7,16], and, consequently, a high sensitivity of DNA detection, which is extremely important for the development of a highly sensitive multiplexed DNA detection assay. Figure 7 (a) shows an example of the fluorescence spectra of labeled probe-DNA hybridized with the anchor-DNA/SiF surface.…”