Single-particle detection of cholesterol based on the host-guest recognition induced plasmon resonance energy transfer

Plasmon resonance energy transfer (PRET) occurs between the plasmonic nanoparticles (NPs) and organic dyes forming donor-acceptor pairs, which has great potential in quantitative analytical chemistry because of its excellent sensitivity under dark-field microscopy (DFM). Herein, we introduce supramolecular β-cyclodextrin (β-CD) to design a host-guest recognition plasmonic nano-structure modified gold nanoparticles (GNPs), while GNPs and rhodamine molecule (RB) act as the donor and acceptor, respectively. In the presence of the target cholesterol, due to the stronger binding of cholesterol with β-CD, RB molecules are released, inducing the inhibition of PRET, as well as the increase of the scattering intensity of GNPs. The proposed strategy achieves a linear range from 0.02 µmol/L to 2.0 µmol/L for cholesterol detection, and reaches a limit of detection (LOD) of 6.7 nmol/L. This host-guest recognition strategy can easily integrate receptor-donor pair into one nanoparticle, which simplifies the construction of the PRET platform, and further provides an effective approach for PRET-based analytical applications. Afterwards, the proposed PRET strategy was successfully applied for the detection of cholesterol in serum samples with high sensitivity and specificity. The proposed method provides an effective clinically potential means for the detection of cholesterol and other disease-related biomarkers.