The design and exploration
of highly efficient organic luminophores
for an electrochemiluminescence (ECL) sensor is a fascinating and
promising subject. Herein, we present a surfactant-assisted self-assembly
of 5,10,15,20-tetrakis (4-carboxyphenyl) porphyrin (TCPP) J-aggregate
as a robust organic luminophore to construct the solid-state ECL sensing
platform with significantly enhanced and constantly stable signals,
by using peroxydisulfate (S2O8
2–) as the coreactant, and l-cysteine capped zinc oxide nanoflowers
(ZnO@Cys NFs) as the multifunctional energy donor and coreactant accelerator.
Compared with TCPP monomer, this TCPP J-aggregate possesses a unique
aggregation-induced electrochemiluminescence (AIECL) performance,
which results in 5-fold enhancement in red-light ECL emission at 675
nm. The resonance energy transfer from the ZnO@Cys NFs (energy donor)
to the TCPP J-aggregate (energy acceptor) substantially improves the
ECL intensity and stability. ZnO@Cys NFs have also been used as a
coreactant accelerator to promote the conversion of more S2O8
2– into SO4
•–. The corresponding ECL mechanism has been investigated by UV–vis
absorption spectrum, photoluminescence, ECL, and density functional
theory. Since l-cysteine on ZnO@Cys NFs can efficiently realize
bidentate chelation with Cu2+, the proposed ECL sensor
shows a highly selective and sensitive quenching effect for the detection
of Cu2+ with a wide linear range from 1.0 pmol·L–1 to 500 nmol·L–1 and a detection
limit of 0.33 pmol·L–1, paving a bright research
direction for the development of TCPP aggregates in ECL field.
A series of novel
luminescent nanostructured coordination polymers
(Ce–Ru–NCPs) with tunable morphologies have been successfully
synthesized on a large scale at room temperature by a facile and rapid
solution-phase method using Ce3+ and tris(4,4′-dicarboxylicacid-2,2′-bipyridyl)
ruthenium(II) dichloride (Ru(dcbpy)3
2+). Among
them, the flowerlike Ce–Ru–NCP shows good cathodic electrochemiluminescence
(ECL) characteristics. The ECL efficiency of the Ce–Ru–NCP/S2O8
2– system is about 2.34 times
that of the classic tris(2,2′-bipyridyl) ruthenium(II) dichloride/S2O8
2– (Ru(bpy)3
2+/S2O8
2–) system.
Hence, we report a sensitive ECL biosensor for microRNA-141 (miRNA-141)
detection based on the flowerlike Ce–Ru–NCP as a cathodic
ECL luminophore and a bipedal three-dimensional (3D) DNA walking machine
as a signal amplifier. Through the bipedal 3D DNA walking machine,
trace targets can be converted to substantial secondary targets (marked
with the quencher dopamine), and a significant quenching effect on
the ECL signal is achieved. As a result, the proposed biosensor exhibits
a relatively good sensitivity for miRNA-141 detection and shows a
dynamic range from 1.0 × 10–16 to 1.0 ×
10–6 mol·L–1 with a limit
of detection (LOD) of 33 amol·L–1 (S/N = 3). The Ce–Ru–NCP with tunable morphologies
and high ECL efficiency, intensity, and stability possesses potential
applications in ECL analysis.
A photoelectrochemical (PEC) biosensor is a very efficient and sensitive detection technology for the quick and effective conversion of light to electrical signals. However, the sensitivity and stability of the sensors are still unsatisfactory based on single-phase semiconductors or in the absence of sacrificial agents in the test solution. Herein, we present an efficient curing sacrificial agent-induced dual-heterojunction PEC system, which can detect the prostate-specific antigen (PSA) with high sensitivity. This PEC immune system was initially fabricated using singlewalled carbon nanohorns (SWCNHs), p-type MoS 2 , and n-type Ag 2 S successively through a Schottky junction and p−n heterojunction on a glassy carbon electrode with electrodeposited gold nanoparticles. Then, the capture antibody (Ab1) was modified and the nonspecific binding sites were sealed off. Meanwhile, the ferrocene (Fc) solidified with hollow nanospheres of zinc ferrite (ZnFe 2 O 4 ) served as a curing electronic sacrificial agent (Fc-ZnFe 2 O 4 ). Next, the detection antibody labeled with Fc-ZnFe 2 O 4 (Ab2-Fc-ZnFe 2 O 4 ) was used as a bio-nanoprobe and captured by PSA and Ab1 via sandwich immunorecognition. Under white light, PEC signal amplification could be driven by the curing electronic sacrificial agent-induced dual-heterojunction to achieve the highly sensitive detection of the target. This proposed system exhibited excellent photocurrent performance within the working range from 1 fg•mL −1 to 100 ng•mL −1 at a low detection limit of 0.44 fg•mL −1 (S/N = 3). The proposed strategy features high sensitivity, selectivity, and stability that provides a new opportunity for the development of biosensors in the PEC field.
A self-enhanced photoelectrochemical copper ions sensor was constructed using an organic electron donor matrix with Schottky heterostructure prepared by dopamine and single walled carbon nanohorns. The determination in a non-additional...
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