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Sensitive Insulin Detection based on Electrogenerated Chemiluminescence Resonance Energy Transfer between Ru(bpy)32+ and Au Nanoparticle-Doped β‑Cyclodextrin-Pb (II) Metal−Organic Framework Hongmin Ma,† Xiaojian Li,† Tao Yan,‡ Yan Li,† Haiyang Liu,† Yong Zhang,† Dan Wu,† Bin Du,‡ and Qin Wei* †
Key Laboratory of Chemical Sensing & Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, People’s Republic of China ‡ School of Resources and Environment, University of Jinan, Jinan 250022, People’s Republic of China S Supporting Information *
ABSTRACT: A novel sandwich-type electrochemiluminescent (ECL) biosensor based on ECL resonance energy transfer (RET) was developed for the determination of insulin. Au nanoparticle-doped Pb(II)-β-cyclodextrin (Pb-β-CD) metal− organic framework was exploited as an ECL donor and chitosan/Ru(bpy)2+ 3 /silica nanoparticles (CRuSi NPs) were employed as ECL acceptor. Pb-β-CD shows excellent ECL behavior and unexpected reducing ability toward AuCl4−. Au nanoparticles could massively form on the surface of Pb-β-CD (Au@Pb-β-CD) without use of any additional reducing agent. In the presence of co-reactant K2S2O8, the ECL emission of Pb-β-CD was enhanced by the formation of Au nanoparticles, which is desirable for the construction of a RET immunosensor. The absorption spectra of the synthesized CRuSi NPs show great overlaps with the ECL spectra of Pb-β-CD. This enabled the ECL-RET by incorporating Au@Pb-β-CD and CRuSi NPs into electrode surfaces. The immunosensor is fabricated using Au@Pb-β-CD as sensing platform and CRuSi NPs as labels of antibodies. After the optimization of determination conditions, a linear response range for insulin from 0.1 pg mL−1 to 10.0 ng mL−1 was obtained, and the limit of detection was calculated to be 0.042 pg mL−1 (S/N = 3). The prepared insulin biosensor displayed excellent stability and good specificity. KEYWORDS: ECL resonance energy transfer, Pb-β-cyclodextrin, insulin, Au nanoparticles, spectral overlap
1. INTRODUCTION Electrochemiluminescence resonance energy transfer (ECLRET) has been widely used in fabricating biosensors, such as high sensitivity, unselective photoexcitation without background, scattered light without interference, and cheap instruments.1−4 According to the mechanism of luminescence resonance energy transfer (LRET), ECL-RET is due to the energy transfer from donor to acceptor.5 The successful establishment of a LRET system requires not only the close proximity (
