Nowadays, electrochemiluminescence (ECL) efficiency of an organic emitter is closely related with its potential applications in food safety and environmental monitoring fields. In this work, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine (TATB) was self-assembled to form hydrogen bond organic frameworks (HOFs), which worked as ideal reactors to generate highly active oxygen-containing radicals, followed by linking with isoluminol (ILu) via amide bond (termed ILu-HOFs). After covalent assembly with aminated indium−tin oxide electrode (labeled NH 2 -ITO), the ECL efficiency of the ILu-HOFs NH 2 -ITO showed about a 23.4time increase over that of ILu itself in the presence of H 2 O 2 . Meanwhile, the enhanced ECL mechanism was mainly studied by electron paramagnetic resonance, theoretical calculation, and electrochemistry. On the above foundation, an aptamer "sandwich" ECL biosensor was constructed for detecting isocarbophos (ICP) via in situ elimination of H 2 O 2 with catalase-linked palladium nanocubes (CAT-Pd NCs). The as-built sensor showed a broad linear range (1 pM to 100 nM) and a low limit of detection (LOD) down to 0.4 pM, coupled with efficient assays of ICP in lake water and cucumber juice samples. This strategy provides an effective way for the synthesis of advanced ECL emitter, coupled by showing promising applications in environmental and food analysis.
Nowadays,
aggregation quenching of most organic photosensitizers
in aqueous media seriously restricts analytical and biomedical applications
of photoelectrochemical (PEC) sensors. In this work, an aggregation-enhanced
PEC photosensitizer was prepared by electrostatically bonding protoporphyrin
IX (PPIX) with an ionic liquid of 1-butyl-3-methylimidazole tetrafluoroborate
([BMIm][BF4]), termed as PPIX-[BMIm] for clarity. The resultant
PPIX-[BMIm] showed weak photocurrent in pure dimethyl sulfoxide (DMSO,
good solvent), while the PEC signals displayed a 44.1-fold enhancement
in a water (poor solvent)/DMSO binary solvent with a water fraction
(f
w) of 90%. Such PEC-enhanced mechanism
was critically studied by electrochemistry and density functional
theory (DFT) calculation in some detail. Afterward, a label-free PEC
cytosensor was built for ultrasensitive bioassay of acute lymphoblastic
leukemia (molt-4) cells by electrodepositing Au nanoparticles (Au
NPs) on the PPIX-[BMIm] aggregates and sequential assembly of protein
tyrosine kinase (PTK) aptamer DNA (aptDNA). The resultant cytosensor
showed a wide linear range (300 to 3 × 105 cells mL–1) with a limit of detection (LOD) as low as 63 cells
mL–1. The aggregation-enhanced PEC performance offers
a valuable and practical pathway for synthesis of advanced organic
photosensitizer to explore its PEC applications in early diagnosis
of tumors.
Heterometallic nanomaterials (HMNMs) display superior physicochemical properties and stability to monometallc counterparts, accompanied by wider applications in fields of catalysis, sensing, imaging, and therapy due to the synergistic effects between...
A total antioxidant capacity (TAC) assay plays an essential
role
in evaluating antioxidant behaviors. It mainly involves examining
the dosages of antioxidants such as ascorbic acid (AA), while TAC
can be measured by nanozyme with peroxidase-like activity. Herein,
nitrogen-doped carbon nanoflowers decorated with uniform PtNi nanoparticles
(PtNi/NCFs) were fabricated by a simple pyrolysis strategy. The obtained
PtNi/NCFs showed high peroxidase-mimicking activity to catalyze 3,3′,5,5′-tetramethylbenzidine
(TMB) oxidation by generating rich hydroxyl radicals (·OH) in
the H2O2 system. By virtue of the PtNi/NCFs
nanozyme, a visual colorimetric sensor was developed for assays of
H2O2 and AA. The limits of detection were as
low as 45.3 and 0.94 μM for determination of H2O2 and AA with linear ranges of 100–1000 and 1.0–20.0
μM, respectively. Moreover, such sensor was also successfully
employed to detect AA and H2O2 in real tablets
and juices. The PtNi/NCFs nanozyme holds great potential for practical
applications.
As a promising biomarker, human epididymis protein 4 (HE4) shows wide applications for early diagnosis and therapy of ovarian cancer. Herein, heterostructured Au nanoparticles/CdS nanosheet (Au NPs/CdS NS) were initially constructed by two-step electrodeposition and used to build photoelectrochemical (PEC) and electrochemical (EC) dual-mode immunosensors for the detection of HE4. As one of appealing properties, surface Plasmon resonance (SPR) effects of Au NPs endowed the Au NPs/ CdS NS heterostructures with highly enhanced PEC and EC signals upon light irradiation, which were gradually weakened by elevating the HE4 concentrations. Under the optimal conditions, the dual-mode sensor displayed wider linear ranges of 0.01−100 and 0.01−200 ng mL −1 for PEC and EC modes, respectively. The detection limits were 1.084 and 1.188 pg mL −1 for PEC and EC detections, respectively. This sensing platform holds great potential for the analysis of other biomarkers in the clinical field.
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