Enhanced Fluorescence Microscopic Imaging by Plasmonic Nanostructures: From a 1D Grating to a 2D Nanohole Array

Abstract

A two‐dimensional (2D) plasmonic coupling nanostructure for enhanced fluorescence observation using a microscope is presented. The substrate contained periodically assembled nanohole arrays with a pitch of 400 nm and a depth of 25 nm. In comparison with one‐dimensional (1D) gratings, this new substrate presented an excellent surface plasmon coupling ability to illuminate light from all directions. Under an optical microscope, an enhancement in the fluorescence intensity of up to 100 times compared with a plain glass slide was observed. The ability to markedly increase the fluorescence intensity means this technique has great potential for application in biodiagnostics, imaging, sensing, and photovoltaic cells.

Fluorescence enhancement by heterostructure colloidal photonic crystals with dual stopbands

“…Currently, many efforts in this area have been directed toward efficient amplification for the fluorescent signal. The most extensively used methods include synthesis of amplifying fluorescent conjugated polymers [2], metal-enhanced fluorescence [3], fluorescence resonance energy transfer [4,5], or surface plasmon resonance [6][7][8][9]. However, those above-mentioned approaches may either strictly rely on the optical properties of the synthesized materials, or experience a certain degree of loss due to diffusion, or be lack of uniformity over large areas for the fluorescent detection, which would restrict their practical application.…”

Hybrid ZnO Nanorod‐Polymer Brush Hierarchically Nanostructured Substrate for Sensitive Antibody Microarrays

“…Some of such substrates are featured of surface-confi ned nanostructures such as macro-/nanoporous silicon, polymers, and porous alumina with huge surface areas for loading of highly dense antibody to capture more targets over a plain surface. [16][17][18][19] Further attempts exploit fl uorescence-enhancing nanomaterials such as photonic crystals, metals, and metal oxides, [20][21][22][23][24][25][26][27] which are able to intrinsically intensify the emission signal of proximal fl uorophores, besides high surface areas for antibody immobilization, to further improve the signal to noise ratio for sensitive microarray detection. We recently reported a zinc oxide (ZnO) nanorod substrate-enhanced fl uorescence microarray with a detection limit as low as 1 pg mL −1 for cancer biomarkers without additional signal amplifi er.…”

ZnO nanorods-enhanced fluorescence for sensitive microarray detection of cancers in serum without additional reporter-amplification

“…Metal-enhanced fluorescence (MEF) has been observed on nanostructured metal materials originated from plasmon-enhanced adsorption and scattering cross-sections of fluorophores (Cui et al, 2010;Sau et al, 2010;Shankar et al, 2009;Wang et al, 2010), but its application is significantly limited by high costs and susceptibility of fluorophore quenching (Dong et al, 2010;Hong and Kang, 2006). A dielectric layer with well-defined thickness is often necessary to spatially separate the fluorophores and the metals to avoid the fluorescence quenching, which is time-consuming and costly.…”