Fluorescence enhancement of acridine orange in a water solution by Au nanoparticles

Abstract

The surface enhanced fluorescence effect of acridine orange fluorophore in the proximity of Au nanoparticles has been investigated experimentally in the system of aqueous solution. Significant enhancement of the fluorescence intensity was observed when the system was excited with 532 nm or 442 nm CW lasers. The influence of the distances between neighboring Au particles as well as that between the fluorophore molecules and the Au surface were explored experimentally. The results demonstrated that a compact distribution of metallic particles was able to produce stronger fluorescence enhancement. Proper separation between the fluorophore molecules and the metal surface was favorable for a better enhancement. surface enhanced fluorescence, local field enhancement, acridine orange, hydrophilic Au nanoparticle PACS: 42.62.Fi, 68.49.Uv, 33.50.Dq, 87.64.NiAs a powerful and broadly used method, fluorescence emission and detection enable the revolution in medical diagnostics, DNA sequencing, and genomics [1]. But it is often limited by low quantum yields and poor photostability in many practical applications [2]. To overcome these difficulties, new approaches for increasing the sensitivity of the detection on the target have been developed [3]. It has been found that the metallic surface has the ability to drastically alter emission of vicinal fluorophores and to enhance the fluorescence intensity [2]. The phenomenon is termed surface enhanced fluorescence (SEF) or metal enhanced fluorescence (MEF) [4]. Investigation of the influence of a metallic surface on the fluorescence emission has a long scientific history, perhaps starting with Drexhage's work [5,6]. Possible mechanisms proposed for understanding experimental observations of SEF include the lighting rod effect, local field effect induced by surface plasmon resonance [7],

Acridine orange tethered chitosan reduced gold nanoparticles: a dual functional probe for combined photodynamic and photothermal therapy

“…14,20 According to the nature of the dye, AO has shown strong absorption at 490 nm. This second band can be assigned to a specic red-shied plasmonic response given by interconnected AuNPs.…”

“…AuNPs have been widely explored as drug delivery vehicles for photosensitizers due to its EPR effect and metallic surface has the ability to enhance the uorescence intensity of the material through surface enhanced uorescence (SEF) or metal enhanced uorescence (MEF). 14 Numerous studies have shown that AuNPs conjugated with photosensitizers are efficient carriers for photodynamic killing of cancer cells by liberating ROS while illuminated with appropriate light source. 15 Photosensitizers like pthalocyanine, indocyanine green, 5-aminolevulinic acid and AlPcS 4 have been successfully tethered on AuNPs and efficiently utilized for the application of imaging and photodynamic therapy.…”

Controlling on the luminescence property of RE ionic and molecular optical centers with nanostructure system

“…(a) Gold nanopillars on a continuous gold surface [38] ; (b) the fabricated nanohole arrays [40] ; (c) gold pyramid array(the inset shows higher resolution image of the gold pyramid at a steep angle) [42] http://engine.scichina.com/doi/10. [46,47] . 为控制金属纳 米颗粒之间及其与探针分子间的距离, 人们采用自 组装方法将所制备的金属胶体沉积于经过硅烷化处 理后的玻璃或者塑料衬底表面 [48,49] , 并通过控制自 组装条件和溶胶浓度等, 探索颗粒间距、荧光分子与 颗粒表面、 荧光分子取向和环境介电常数等对表面增 强荧光效应的影响 [50] .…”

Surface enhanced fluorescence and Raman scattering by gold nanoparticle dimers and trimers

“…19 It is established that the EM field enhancement in both SERS and SEF is due to the localized surface plasmon resonance (LSPR), a class of surface modes that involves the collective excitation of conduction electrons in response to the incident EM field. [20][21][22][23] For gold or silver nanoparticles (NPs), a drastically amplified EM field enhancement is presented in the nanogap between two NPs, which is called "hot spot" phenomenon. 24 In general, the dimeric structures are produced by using the biological or organic linkers, which prevent the analyte molecules enter into the nanogap, and the SES signals were interfered by the linker molecules.…”