摘要
本文报道了粒径小于20nm的球形纳米金颗粒(AuNSs)的强多光子激发荧光,这主要归因于多光子激发过程中的高光子密度引起的局域场增强效应。AuNSs的多光子荧光与影响局域场增强效应的颗粒尺寸及团聚程度有关。基于吸附在纳米金表面的BSA与Anti-BSA的作用引起纳米金团聚导致其多光子荧光增强,结合近红外区的多光子激发可以避免生物分子自发荧光及散射光的干扰这一优势,建立了一种高灵敏、高选择性检测血清中Anti-BSA的均相免疫分析方法。检测的线性范围从1.16nmol/L到35nmol/L,检出限为0.08nmol/L。而且通过在纳米金颗粒表面包覆硅壳实现了纳米金的荧光增强及表面功能化,由此可以建立一系列基于纳米金多光子荧光的分析检测方法。
Gold nanospheres（AuNSs）with diameters larger than the exciton Bohr radius are normally weakly fluorescent due to the lack of discrete band gap,which is the main reason for the very limited analytical application of its fluorescence.In this study,strong fluorescence of AuNSs with a diameter of less than 20 nm driven by a multi-photon excitation process was reported,which was attributed to the increased effect of local field enhancement benefiting from the high photon density of multi-photon excitation.The intrinsic multi-photon fluorescence of AuNSs was found to be dependent on particle size that decides the local field enhancement effect.Based on the fluorescence enhancement resulting from the aggregation of AuNSs,which was induced by the interaction between bovine serum albumin（BSA）adsorbed on the surface of AuNSs and Anti-BSA,a homogeneous immunoassay method for Anti-BSA was constructed with satisfying sensitivity and specificity.Good linearity was obtained with the AntiBSA concentration ranging from 1.16nmol/L to 35.0nmol/L with a detection limit of 0.08nmol/L.The assay was directly conducted in serum with no background interference observed,indicating the ability of multi-photon excitation in near infrared（NIR）region to overcome the autofluorescence of biomolecules and scattering light.Through coating the particles with a silica shell,enlarged fluorescence intensity and functionalized surface of AuNSs were achieved,which laid a foundation for expanding the analytical applications.This work opened the opportunity for developing a catalog of new analytical methods based on multi-photon fluorescence of AuNSs.
出处
《分析科学学报》
CAS
CSCD
北大核心
2014年第5期637-643,共7页
Journal of Analytical Science
基金
国家自然科学基金(No.21375098)
