Enhanced Electrochemiluminescence of Graphitic Carbon Nitride by Adjustment of Carbon Vacancy for Supersensitive Detection of MicroRNA

Abstract

Herein, a supersensitive biosensor was constructed by using graphitic carbon nitride with a carbon vacancy (V C -g-C 3 N 4 ) as an efficient electrochemiluminescence (ECL) emitter for detection of microRNA-21 (miRNA-21). Impressively, V C -g-C 3 N 4 could be prepared by formaldehyde (HCHO)-assisted urea ploycondensation, and the concentration of the carbon vacancy could be controlled by adjusting the dosage of HCHO to improve the ECL performance, in which the carbon vacancy could improve the charge carrier transfer to enhance the conductivity and it also could be used as an electron trap to prevent electrode passivation and facilitate the adsorption of coreactant S 2 O 8 2− to accelerate its reduction. Compared with original g-C 3 N 4 , the introduction of carbon vacancies resulted in a significant enhancement of the ECL efficiency of V C -g-C 3 N 4 . With the aid of improved cascade strand displacement amplification (IC-SDA), the ECL biosensor realized sensitive detection of miRNA-21 with a low detection limit of 3.34 aM. This successful strategy promoted the development of g-C 3 N 4 in the ECL field to construct the sensitive biosensor for molecular and disease diagnoses.

Zwitterionic Electrochemiluminescence Biointerface Contributes to Label‐Free Monitoring of Exosomes Dynamics in a Fluidic Microreaction Device

“…[ 30 ] Unfortunately, its better ECL usage is still severely limited by a series of drawbacks such as low conductivity, electrode passivation, and poor water solubility. [ 31 ] To solve these problems, here, Ti 3 C 2 T x MXene serves as a unique conductive platform to accommodate protonated g‐C 3 N 4 NSs (pCN). As bulk g‐C 3 N 4 synthesized through classical thermal polycondensation of melamine, urea, and malonamide is in a solid state and hardly touched, the concentrated acid treatment (HCl, 37%) and ultrasonic exfoliation were successively performed to obtain well‐dispersed pCN.…”

Electrochemiluminescence from Single Molecule to Imaging

“…In addition, the efficiency of ECL is also affected by many factors, such as electrode material, co-reactant, imaging buffer, electrolyte, and so on. To enhance the detection and imaging contrast of ECL, the following improvements are under development: the common strategy for positive labeling detection is to synthesize brighter dyes and the enrichment and cascade amplification of luminescent probes or co-reactants such as ECL systems based on quantum dots ,− (see Figure C), porous materials, − single-atom catalyst, − carbon-based materials, − and the rational design of co-reactants. − In addition to the designing of novel ECL probes and co-reactant, the electrode applied in the ECL reaction is an important part of the ECL imaging system, which can also be improved . As a new type of semiconductor electrode, the boron-doped diamond electrode (BDDE) has a good redox window in aqueous solution, which can avoid the side reaction of water electrolysis on ECL .…”

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

“…Polymeric carbon nitride (CN) has emerged as one of the most promising ECL luminophores, which is characterized by tunable luminescent features, good biocompatibility, and stable ECL. ,− Moreover, the rigid 2D backbone of CN can effectively reduce nonradiative transitions, leading to high Φ ECL and brightness. , Herein, using CN as a basic luminophore, we developed a simple and versatile method to grow CN films with tunable ECL emission from blue to green (410, 450, 470, and 525 nm). Naked eye-observable emissions were observed, and the cathodic Φ ECL values of CN-410, CN-450, CN-470, and CN-525 were, respectively, 112, 394, 353, and 251 times that of the aqueous Ru­(bpy) 3 Cl 2 /K 2 S 2 O 8 reference.…”