title: Plasmon-mediated fluorescence with distance independence: from model to a biosensing application.
abstract: In this article, plasmon-mediated fluorescence biosensing is reported to be distance independent through a full-coupling strategy that effectively activates the entire plasmon coupling region. This concept is demonstrated through collecting the directional surface plasmon-coupled emission (SPCE) signal from fluorescent silica nanoparticles with a size that matches the entire coupling region. Based on this design, the spatial distribution of the fluorophores is confined by the dimension of the nanoparticle. Therefore, these encapsulated fluorophores occupy the maximum coupling dominant region and optimally utilize the coupling effect. Being different from the conventional plasmon-mediated fluorescence, the enhanced fluorescence response becomes nearly independent of distance changes on a wide dynamic range from 0nm to 30nm between the fluorescent nanoparticles and metal structure. Full-coupling SPCE appropriately enlarges the distribution of fluorophores, ensuring that the coupling dominant region is filled with enough fluorophores at varying distances to create a stable and detectable signal. This scale of distances is well suited for many biorecognition events. Full-coupling SPCE solves signal deviation challenges originating from the susceptible and unpredictable orientation and conformation of biomolecules on the nanoscale. Immunoassays and DNA detection are shown with high and reliable signals, demonstrating the advantages of distance-independent full coupling. Without the need of a complicated and rigorous architecture for precise distance control, full-coupling SPCE offers great promise for a general platform of chip-based biosensing and bioanalysis.
authors.affiliation: Department of Chemistry and the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
authors.forename: Shuo-Hui
authors.initials: SH
authors.lastname: Cao
authors.affiliation: Department of Chemistry and the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
authors.forename: Zhe-Xiang
authors.initials: ZX
authors.lastname: Zou
authors.affiliation: Department of Chemistry and the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
authors.forename: Yu-Hua
authors.initials: YH
authors.lastname: Weng
authors.affiliation: Department of Chemistry and the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
authors.forename: Wei-Peng
authors.initials: WP
authors.lastname: Cai
authors.affiliation: Department of Chemistry and the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Chemistry and the MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China. Electronic address: yaoqunli@xmu.edu.cn.
authors.forename: Yao-Qun
authors.initials: YQ
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005456:Fluorescent Dyes / Q000032:analysis* / Q000737:chemistry*; D008962:Models, Theoretical; D013050:Spectrometry, Fluorescence / Q000295:instrumentation*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D005456:Fluorescent Dyes
keywords: DNA; Distance independence; Full coupling; Metal-enhanced fluorescence; Protein; Surface plasmon coupled emission