Immuno-Electrochemiluminescent Imaging of a Single Cell Based on Functional Nanoprobes of Heterogeneous Ru(bpy)₃²⁺@SiO₂/Au Nanoparticles

Abstract

It is valuable to develop a sensing platform for not only detecting a tumor marker in body fluids but also measuring its expression at single cells. In the present study, a simple closed bipolar electrodes-based electrochemiluminescence (BPEs-ECL) imaging strategy was developed for visual immunoassay of prostate specific antigen (PSA) at single cells using functional nanoprobes of heterogeneous Ru(bpy)@SiO/Au nanoparticles. Multiple-assisted ECL signal amplification strategy was introduced into the detection system on the basis of the synergetic amplifying effect of the anodic and cathodic amplification. On the basis of the synergetic amplifying effect, the detection limits of PSA by using photomultiplier tube and charge-coupled device (CCD) imaging are 3.0 and 31 pg/mL, respectively. The obtained immunosensor was employed to evaluate PSA levels in serum samples with a satisfying result. Moreover, the obtained functional nanoprobes were used to visually profile the PSA expression on the surface of single LNCaP cells (a kind of prostate cancer cells) based on a bare BPE. The results show that the functional nanoprobes-based ECL imaging immunoassay provides a promising visual platform for detecting tumor markers (proteins and cancer cells) and thus shows a high potential in cancer diagnosis.

Wireless Electrochemical Visualization of Intracellular Antigens in Single Cells

“…) is linked to the antibody that binds with the corresponding antigen specifically to form the immune-complex. 11 Under a certain voltage, the luminophore near the electrode surface is excited to generate the intermediates, which further reacts with the co-reactant to emit the light. 13 By recording the ECL illumination, the established ECL microscopy achieves the visualization of the antigens in plasma membrane at single cells.…”

“…Alternatively, as a near-zero background optical technique, electrochemiluminescence (ECL) is widely used for the sensitive and quantitative detection of various antigens in serum and cells. [8][9][10][11][12] In this process, the luminophore (e.g.…”

Electrochemiluminescence Imaging for Bioanalysis

“…To improve the ECL imaging sensitivity of tumor markers expressed at the cell level, BPE and functional nanoprobes of heterogeneous [Ru(bpy) 3 ] 2+ @SiO 2 /Au nanoparticles were combined for visual immunoassay of prostate specific antigen (PSA) at single cells. 82 Such silica NPs enabled the immobilization of a large amount of labels, and the Au NPs decorated on the surface of [Ru(bpy) 3 ] 2+ @SiO 2 NPs increased the amount of loaded antibody so that more luminescence was obtained.…”

Electrochemiluminescence Single‐Cell Analysis: Intensity‐ and Imaging‐Based Methods

“…Cao et al integrated bipolar electrode with ECL single cell imaging. [66] The cells were incubated on the floating electrode in the anodic pole. By labeling cell surface with ultrasensitive heterogeneous Ru(bpy) 3 2 + @SiO 2 /Au nanoparticles, the prostate specific antigen (PSA) on the cancer cell surface was imaged.…”