Abstract
Enhancement of fluorescence through the application of plasmonic metal nanostructures has gained substantial research attention due to the widespread use of fluorescence-based measurements and devices. Using a microfabricated plasmonic silver nanoparticle–organic semiconductor platform, we show experimentally the enhancement of fluorescence intensity achieved through electro-optical synergy. Fluorophores located sufficiently near silver nanoparticles are combined with diphenylalanine nanotubes (FFNTs) and subjected to a DC electric field. It is proposed that the enhancement of the fluorescence signal arises from the application of the electric field along the length of the FFNTs, which stimulates the pairing of low-energy electrons in the FFNTs with the silver nanoparticles, enabling charge transport across the metal–semiconductor template that enhances the electromagnetic field of the plasmonic nanoparticles. Many-body perturbation theory calculations indicate that, furthermore, the charging of silver may enhance its plasmonic performance intrinsically at particular wavelengths, through band-structure effects. These studies demonstrate for the first time that field-activated plasmonic hybrid platforms can improve fluorescence-based detection beyond using plasmonic nanoparticles alone. In order to widen the use of this hybrid platform, we have applied it to enhance fluorescence from bovine serum albumin and Pseudomonas fluorescens. Significant enhancement in fluorescence intensity was observed from both. The results obtained can provide a reference to be used in the development of biochemical sensors based on surface-enhanced fluorescence.
Highlights
Plasmonic enhanced fluorescence (PEF) is produced through effective coupling of a metal nanostructure localized surface plasmon resonance (LSPR) with photoexcited fluorophores to increase their photoluminescence signal intensity
We show that this optoelectrical device significantly boosts the PEF emission from a range of systems, including molecules, nanocrystals, proteins, and bacteria, exploiting facile field-activated trans-template charge transfer processes and resulting in a strengthening of the plasmonic electromagnetic mechanism
Gold electrodes were prepared on Si substrates, with aligned AgNPdecorated FFNTs formed between the electrodes
Summary
Plasmonic enhanced fluorescence (PEF) is produced through effective coupling of a metal nanostructure localized surface plasmon resonance (LSPR) with photoexcited fluorophores to increase their photoluminescence signal intensity. Article stability,[26,27] as well as their easy chemical preparation that does not require heavy metals, strong acids, or harsh chemical substances.[26,27] Among the numerous peptide-molecule-based nanostructures, diphenylalanine (Phe-Phe, FF) is a frequently used building-block peptide that can form various structures such as nanotubes through self-assembly processes.[28,29] Diphenylalanine can self-assemble into various morphologies, including nanotubes (FFNTs), which are wide-band-gap semiconductor organic materials.[30] FFNTs show chemical and thermal stability[31] and mechanical strength,[32] additional features required for optical, electrical, and biological applications.[33] Several studies have shown the application of a plasmonic−semiconductor template formed from aligned FFNTs to enhance both chemical reactions and surfaceenhanced scattering intensity, accomplished through electrooptical synergy.[12,34,35] Here, we demonstrate for the first time the enhancement of fluorescence intensity via field-activated microfabricated plasmonic nanostructures combined with an organic FFNT template We show that this optoelectrical device significantly boosts the PEF emission from a range of systems, including molecules, nanocrystals, proteins, and bacteria, exploiting facile field-activated trans-template charge transfer processes and resulting in a strengthening of the plasmonic electromagnetic mechanism. Because of its high sensitivity, this proof-of-principle microfabricated plasmonic template opens up the possibility to use such devices in early-stage disease diagnosis and biosensing applications
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
