Electrochemiluminescence Immunoassay Platform with Immunoglobulin G-Encapsulated Gold Nanoclusters as a “Two-In-One” Probe

Abstract

Biomolecule-functionalized Au nanoclusters (AuNCs) have drawn great interest in the electrochemiluminescence (ECL) field due to their unique optical/electrical properties, biocompatibility, and versatile bioapplication potentials. Herein, we proposed a two-in-one ECL probe of immunoglobulin Gencapsulated AuNCs (IgG-AuNCs) for the development of a highperformance ECL immunoassay (ECLIA) platform. The IgG-AuNCs were not only used as an ECL probe due to their excellent anodic ECL performance with triethylamine (TEA) as a coreactant but also used as the biorecognition element because of their wellretained bioactivity of the IgG. As a proof of concept, a new type of competitive immunosensing platform has been applied to detect IgG representing several merits of facile preparation, rapid detection, sample saving, and good analytical performance. The sensing platform exhibited a linear range of 0.5−50,000 ng/mL with a limit of detection of 0.06 ng/mL for IgG detection with high selectivity. In addition, this convenient ECLIA platform also performed well in real serum sample detection. Notably, our work not only proved the "two-in-one" immuno-AuNC probe-based ECLIA strategy but also developed a rational framework for study of ECL bioassay platforms based on multifunctional AuNCs and other related nanomaterials.

Co-Reactant-Mediated Low-Potential Anodic Electrochemiluminescence Platform and Its Immunosensing Application

“…The Au electrode (AuE) was treated according to the reported work . First, 5 μL of BSA-AuNCs was dropped on the electrode and incubated at 37 °C for 1 h. The modified AuE was then thoroughly rinsed with ultrapure water and dried under nitrogen for use.…”

“…With excellent stability, adjustable functions, and special photoelectric properties, gold nanoclusters (AuNCs) are prominent in metal nanoclusters, which have been used as newly emerged ECL probes in recent years. − Since the first report for the ECL of AuNCs, various AuNC-based ECL systems with TEA as a co-reactant have been widely studied. − However, their high triggering potential has aroused much attention. To further expand the application of AuNCs in the field of biomedical analysis, great efforts have been made to reduce the anode ECL potential of AuNCs.…”

Recent progress of metal nanoclusters in electrochemiluminescence

“…2A). 10 Bovine serum albumin (BSA) 23,27,47,57,61 and immunoglobulin G (IgG) 48 with asymmetric hydrophilic/hydrophobic structures act as both protein templates and reductants, providing a suitable microenvironment for MeNC landing.…”

“…41 Hong et al utilized IgG-AuNCs as a “two-in-one” ECL probe for competitive immunosensing of IgG, presenting the superiorities of sample saving, simple preparation, rapid determination, and excellent analytical performance. 48 Jia et al established an ECL sensing platform using polypeptide-biomineralized AuNCs as signal transducers and Fe 2 O 3 nanoarrays as well-ordered coreaction promoters, enabling the ultrasensitive label-free determination of Cyfra 21-1 , a major biomarker of nonsmall cell lung cancer. 24 Song et al designed a peptide-based ECL biosensor utilizing AgNCs as signal labels and Pd–Cu 2 O hybrid nanoconcaves as coreactant accelerators for immunoassay of neuron-specific enolase, which is important for early diagnosis and prognostic assessment of small cell lung cancer.…”

“…2A). 10 Bovine serum albumin (BSA) 23,27,47,57,61 and immunoglobulin G (IgG) 48 with asymmetric hydrophilic/hydrophobic structures act as both protein templates and reductants, providing a suitable microenvironment for MeNC landing. Polymers with plentiful charges and hydrophobic groups, such as poly(methacrylic acid) (PMAA), 13 hyperbranched polyethylenimine (hPEI), 38 polyamidoamine dendrimer (PAMAM), 39 and special DNA templates, 37,64 can engineer the MeNCs surface and regulate their physicochemical properties.…”