Efficient and Monochromatic Electrochemiluminescence of Aqueous‐Soluble Au Nanoclusters via Host–Guest Recognition

Abstract

Inspired by the enhanced photoluminescence of Au nanoclusters (AuNCs) with a rigid shell, the formation of rigid host–guest assemblies on AuNC surfaces was employed to screen novel electrochemiluminophores with 6‐aza‐2‐thiothymine(ATT)‐protected AuNCs (ATT‐AuNCs) and l‐arginine (ARG) as models for the first time. The rigid host–guest assemblies formed between ARG and ATT on the ATT‐AuNC surface enabled aqueous‐soluble ARG/ATT‐AuNCs with a dramatically enhanced electrochemiluminescence (ECL) compared to ATT‐AuNCs. This includes one cathodic ECL process (−1.30 V) and three anodic ECL processes (+0.78, 0.90, and 1.05 V) in a so‐called half‐scan experiment without a co‐reactant, as well as a 70‐fold enhanced oxidative‐reduction ECL at +0.78 V with tri‐n‐propylamine as a co‐reactant. Importantly, the ECL of the ARG/ATT‐AuNCs is highly monochromatic with an emission maximum around 532 nm and a full width at half‐maximum of 36 nm, which is of great interest for color‐selective ECL assays.

Highly Efficient Wavelength-Resolved Electrochemiluminescence of Carbon Nitride Films for Ultrasensitive Multiplex MicroRNA Detection

“…To date, several strategies have been employed to amplify ECL signals, including self-enhancement, 15,20−22 radical stabilization, 23,24 aggregation-induced ECL, 25,26 pre-oxidation, 27 and host−guest recognition. 28 Despite these unprecedented successes, the study of ECL luminophores with strong ECL emission and the associated mechanism is still at the initial stage. The high requirements for ECL luminophores compared with fluorescence, that is, the unstable radicals in aqueous solutions and the complexity of the electron-transfer processes in the ECL process, make the associated mechanisms elusive.…”

“…To date, several strategies have been employed to amplify ECL signals, including self-enhancement, ,− radical stabilization, , aggregation-induced ECL, , pre-oxidation, and host–guest recognition . Despite these unprecedented successes, the study of ECL luminophores with strong ECL emission and the associated mechanism is still at the initial stage.…”

Cucurbituril Enhanced Electrochemiluminescence of Gold Nanoclusters via Host–Guest Recognition for Sensitive D-Dimer Sensing

“…Owing to the size approaching the Fermi wavelength of electrons, AuNCs exhibit molecule-like quantum confinement effects. In recent years, AuNCs have been used in the ECL biosensing field due to their uniform and controllable size, biocompatibility, and stable optical properties. − Despite swift progress in the ECL application of AuNCs, it still turns out to be rather challenging for realizing simple synthesis, excellent stability, and high ECL efficiency, which is critical for improving their performance in the ECL biosensing application. − It has been demonstrated that passivation and reduction of the surface energy can enhance the stability and improve the ECL performance of AuNCs. − In this respect, cucurbit[7]­uril (CB[7]) assisted supramolecular self-assembly is probably a desirable and straightforward strategy − for enhancing the ECL intensity and stability of AuNCs. CB[7] is a highly rigid, pumpkin-shaped macrocyclic supermolecule comprising seven glycoluril units bridged by methylene groups. − Under the impacts of various non-covalent interactions such as hydrogen bond effect, hydrophobic effects, the polar and hydrophobic inner cavity, ion-dipole, and two portals with the negative charge, CB[7] exhibits binding solid force with the specific guest in aqueous solution, forming a stable host–guest complex. − The outstanding rigidity, water solubility, and supramolecular recognition ability − allow CB[7] to act as “intelligent molecular shackles” to recognize and limit the vibrations and interactions of ligands on the surface of Au NCs.…”

Fluorescent Noble Metal Nanoclusters Loaded Protein Hydrogel Exhibiting Anti‐Biofouling and Self‐Healing Properties for Electrochemiluminescence Biosensing Applications

“…[ 1–3 ] By far, remarkable efforts have been made to develop various types of ECL based biosensing systems, [ 4,5 ] and the recent introduction of new ECL materials or mechanisms, such as metal‐organic frameworks, aggregation‐induced emission luminogens or single atom catalysts, further improved the performance and application ranges of ECL based biosensing systems. [ 6–11 ] However, as a method extremely sensitive to the state of the electrode surface, nonspecific adsorption of biological macromolecules, in particular proteins, and physical scratches of the electrode surfaces, during the sensing of complex biological samples, severely affects the accuracy and practical applicability of the ECL biosensing systems. [ 12 ] In order to meet the requirements of anti‐interference and long‐term application in practical biosensing applications, it is highly demanded to develop ECL biosensing systems with anti‐biofouling and self‐healing properties.…”