High-Density N-Vacancy-Induced Multipath Electrochemiluminescence Improvement of 3D g-C₃N₄ for Ultrasensitive MiRNA-222 Analysis

Abstract

Using dissolved O2 as the cathodic co-reactant of three-dimensional (3D) g-C3N4 is a convenient method to improve the electrochemiluminescence (ECL) signal, but it still suffers the disadvantages of limited luminous efficiency of 3D g-C3N4 and low content, low reactivity, and instability of dissolved O2. Here, N vacancy with high density was first introduced into the structure of 3D g-C3N4 (3D g-C3N4-NV), which could conveniently realize multipath ECL improvement by simultaneously solving the above shortcomings effectively. Specifically, N vacancy could change the electronic structure of 3D g-C3N4 to broaden its band gap, increase fluorescence (FL) lifetime, and accelerate electron transfer rate, obviously improving the luminous efficiency of 3D g-C3N4. Meanwhile, N vacancy made the excitation potential of 3D g-C3N4-NV to shift from −1.3 to −0.6 V, effectively weakening the electrode passivation. Moreover, the adsorption capacity of 3D g-C3N4-NV was obviously enhanced, which could make the dissolved O2 enrich around 3D g-C3N4-NV. And massive active NV sites of 3D g-C3N4-NV could promote O2 to more efficiently convert to reactive oxygen species (ROS) that were key intermediates in ECL generation. Using the newly proposed 3D g-C3N4-NV-dissolved O2 system as an ECL emitter, an ultrasensitive target conversion biosensor was constructed for miRNA-222 detection. The fabricated ECL biosensor exhibited satisfactory analytical performance for miRNA-222 with a detection limit of 16.6 aM. The strategy achieved multipath ECL improvement by introducing high-density N vacancy simply in the 3D structure of g-C3N4 and could open a new horizon for developing a high-performance ECL system.

Renewable Electrochemiluminescence Biosensor Based on Eu-MOGs as a Highly Efficient Emitter and a DNAzyme-Mediated Dual-drive DNA Walker as a Signal Amplifier for Ultrasensitive Detection of miRNA-222

“…Besides, the real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was applied to further verify the accuracy of the biosensor we proposed, as depicted in Figure S10. The above results indicated the expression level of miRNA-222 in MHCC-97L (high level) and HeLa (low level), which is consistent with the previous report …”

One-Dimensional Covalent Organic Framework with Improved Charge Transfer for Enhanced Electrochemiluminescence

“…In general, more radiative processes lead to longer PL lifetime, while nonradiative processes lead to shorter PL lifetime, and thus the changes in PL lifetime may indicate the change in nonradiative and radiative recombination . The PL lifetime curves of 2D-COF and 1D-COF are well-fitted by using the exponential model, and the average PL lifetime is 2.34 ns for 1D-COF (Figure B) and 2.26 ns for 2D-COF (Figure D).…”

Unmasking the Electrochemiluminescence Properties of Ternary Mn/Fe/Co Metals Doped Porous g-C3N4 Fiber-like Nanostructure

“…Among the potential candidates, g-C 3 N 4 stands out as a promising option due to its earth-abundant nature, safety, cost-effectiveness, and exceptional biocompatibility. − This is in addition to the facile synthesis in a high yield (i.e., several kilograms in one run) from earth-abundant resources using various methods (i.e., annealing, autoclaving, and hydrothermal). Despite the prevalent use of g-C 3 N 4 nanosheets in the realm of g-C 3 N 4 ECL, these systems often encounter challenges arising from limited stability and efficiency, primarily attributable to factors such as poor electrical conductivity, low-surface area, inferior redox properties, charge accumulation, and electrode passivation effects, which severely curtail the widespread applicability of g-C 3 N 4 in ECL. − To surmount these hurdles, extensive research endeavors have been directed toward modifying the chemical structure of g-C 3 N 4 nanosheets through various techniques, including noble metal loading (Au-g-C 3 N 4 ), − heteroatom doping (P-g-C 3 N 4 ), , nitrogen vacancy engineering, and transitional metal doping . Despite the notable progress achieved through these approaches, the scarcity of g-C 3 N 4 nanomaterials suitable for ECL purposes remains a pressing issue .…”