School of Chemical Engineering, Sungkyunkwan University, Suwon 440-746, Korea.
Small. 2013 Oct 25;9(20):3485-92. doi: 10.1002/smll.201202638. Epub 2013 Apr 19.
A strategy for attomolar-level detection of small molecule-size proteins is reported based on Rayleigh light scattering spectroscopy of individual nanoplasmonic aptasensors by exploiting the outstanding characteristics of gold colloids to amplify the nontransparent resonant signal at ultralow analyte concentrations. The fabrication method utilizes thiol-mediated adsorption of a DNA aptamer on the immobilized Au nanoparticle surface, the interfacial binding characteristics of the aptamer with its target molecules, and the antibody-antigen interaction through plasmonic resonance coupling of the Au nanoparticles. Using lysozyme as a model analyte for disease detection, the detection limit of the aptasensor is ∼7 × 10(3) aM, corresponding to the LSPR λmax shift of ∼2.25 nm. Up to a 380% increase in the localized resonant λmax shift is demonstrated upon antibody binding to the analyte compared to the primary response during signal amplification using immunogold colloids. This enhancement leads to a limit of detection of ∼7 aM, which is an improvement of three orders of magnitude. The results demonstrate substantial promise for developing coupled plasmonic nanostructures for ultrasensitive detection of various biological and chemical analytes.
本文报道了一种基于单个纳米等离子体适体传感器的瑞利光散射光谱，在超低分析物浓度下利用胶体金放大非透明共振信号，实现对小分子蛋白质的 attomolar 级检测的策略。该制备方法利用巯基介导的 DNA 适体在固定化 Au 纳米颗粒表面的吸附、适体与靶分子的界面结合特性以及通过 Au 纳米颗粒的等离子体共振耦合的抗体-抗原相互作用。以溶菌酶作为疾病检测的模型分析物，该适体传感器的检测限约为 7×10(3) aM，对应于 LSPR λmax 位移约为 2.25nm。与信号放大过程中免疫金胶体的初级响应相比，抗体与分析物结合后，局部共振 λmax 位移增加了 380%。这种增强导致检测限约为 7 aM，提高了三个数量级。结果表明，开发用于各种生物和化学分析物的超灵敏检测的耦合等离子体纳米结构具有很大的应用前景。
