Electrochemiluminescence Cytosensor Research Articles

Electrochemiluminescent evaluation of GLUT4 expression in rat adipocytes induced by Ganoderma lucidum polysaccharides

Glucose transporter 4 (GLUT4) directly facilitates cellular uptake of glucose and plays a crucial role in mammalian adipose tissue glucose metabolism. In this work, we constructed a cytosensor for sensitive electrochemiluminescence (ECL) detection of GLUT4 in rat adipocytes (RA cells). A carbon nanotube sponge (CNTSP) was selected to fabricate a permeable electrode to overcome the steric hindrance of cells on the electrode. The expression of GLUT4 after treatment with Ganoderma lucidum polysaccharide (GLP) was assessed by analyzing the luminescence emitted from cell-surface ECL probes. Our preliminary results suggest that GLP promote the expression of GLUT4, thereby enhancing the uptake of the fluorescent glucose 2-NBDG. Treatment with GLP affected GLUT4 expression in RA cells in a dose-dependent manner. Additionally, the ECL cytosensor contributes to the development of ECL imaging of receptors on the cell surface for clinical drug evaluation.

A novel electrochemiluminescent cytosensor using 3D multivalent aptamer recognition and covalent organic frameworks-associated DNA walker for highly efficient capture and detection of rare CTCs

Circulating tumor cells (CTCs) are regarded as promising biomarkers for early clinical diagnosis, prognosis evaluation, and treatment monitoring. However, their limited abundance in peripheral blood and phenotypic heterogeneity resulting from epithelial-mesenchymal transition (EMT) present significant challenges for accurate detection of CTCs. Herein, we developed an ultrasensitive and highly specific cytosensor to address these limitations. Firstly, to overcome the EMT property of CTCs, we designed a novel 3D multivalent aptamer recognition strategy (MARS), which not only contributed to highly efficient capture of heterogeneous CTCs, but also guaranteed detection sensitivity of the developed cytosensor. Meanwhile, we integrated an exonuclease III (Exo III)-mediated DNA walking signal amplification strategy into the electrochemiluminescence (ECL) cytosensor, enhancing its sensitivity in detecting rare CTCs. Furthermore, in combination with the excellent ECL performance of the luminescent nanomaterials (Au@COF-LZU1@Ru), the cytosensor exhibited a wide detection range from 8 to 1 × 105 cells/mL with a detection limit as low as 2 cells/mL. The analytical performance of the constructed cytosensor was validated through real sample analysis (AUC = 0.97), demonstrating its potential for clinical applications. The novel cytosensor offers an effective and reliable tool for the detection of rare CTCs, thereby paving the way for improved clinical significance.

PtNi nanocubes-catalyzed tyramine signal amplification electrochemiluminescence sensor for nonenzymatic and ultrasensitive detection of hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is a life-threatening malignant tumor with high cancer mortality, therefore it is particularly important to sensitively detect the biomarkers of hepatocellular carcinoma for early diagnosis and treatment. In this work, a nonenzymatic and ultrasensitive electrochemiluminescence (ECL) cytosensor for HepG2 cells detection is established based on the PtNi nanocubes-catalyzed tyramine signal amplification. PtNi nanocubes (PtNi NCs) are firstly reported to catalyze tyramine-luminol (Tyr-Lum) with the aid of H2O2 for covalently binding to membrane proteins of HepG2 cells, realizing the introduction of massive Tyr-Lum ECL luminophores for signal amplification. Besides, PtNi NCs could also enhance the ECL signal of luminol-H2O2 system. On the basis of bifunctional PtNi NCs, the developed ECL cytosensor for HepG2 cells detection shows a wider linear range of 1 × 10 to 1 × 105 cells mL−1 with detection limit of 3 cells mL−1. This proposed enzyme-free-mediated tyramine signal amplification inspires a new strategy for applications in the early diagnosis of cancer cells.

Electrochemiluminescence cytosensing platform based on Ru(bpy)32+@silica-Au nanocomposite as luminophore and AuPd nanoparticles as coreaction accelerator for in situ evaluation of intracellular H2O2

An electrochemiluminescence (ECL) cytosensor was fabricated onto a microfluidic paper-based analytical device (μ-PAD) in order to detect hydrogen peroxide (H2O2) which was released from tumor cells. The ECL probe Ru(bpy)32+@silica-Au nanocomposite (Ru@SiO2-Au) was fabricated and served as ECL reagent. The ECL of Ru@SiO2-Au nanocomposite was quenched by the ferrocene (Fc). AuPd nanoparticles (AuPd NPs), which were modified on the paper working electrode (PWE), were served as the catalyst of H2O2 to produce hydroxyl radicals (•OH) for cleaving Fc-labelled DNA to achieve “signal-on”, and AuPd NPs also severed as coreaction accelerator. H2O2 was released from cells under the stimulation of phorbol myristate acetate. Fc-labelled DNA strand was cleaved via •OH. Fc molecule departed from the PWE surface, The ECL could be recovered. An ECL cytosensor on a 3D origami device was constructed. The ECL response of the Ru@SiO2-Au-Fc system was related to the number of cells. The ECL intensity was quantitatively related with the logarithm of MCF-7 cells number and H2O2 concentration, the detection limit was 30 cells mL−1. As a consequence, this work provided a really low-cost and disposable μ-PAD for sensitive detection of intracellular H2O2. What's more, this work had potential application value for studying cellular biology and pathophysiology.

Signal-On Electrochemiluminescence of Self-Ordered Molybdenum Oxynitride Nanotube Arrays for Label-Free Cytosensing

In this paper, a signal-on electrochemiluminescence (ECL) cytosensing platform was developed based on nitrogen doped molybdenum oxynitride nanotube arrays (MoO xN y NTs) for the first time. The MoO xN y NTs exhibited excellent cathodic ECL behavior with 2-(dibutylamino)-ethanol (DBAE) as a coreactant. Owing to the surface plasmon resonance (SPR) of Au triggered by the ECL emission, the generation of "hot electrons" on AuNPs hampered DBAE to give off electrons and leads to the ECL quenching. This process could be hindered via adding "barriers" on the surface of AuNPs, such as antibody molecules and cells, to achieve the signal recovery. Based on the quenching-recovering mechanism, a facile label-free ECL cytosensor was constructed. The linear response of HepG2 cells was in the range of 50-13800 cells mL-1 with a low detection limit of 47 cells mL-1 (S/N = 3). Moreover, the proposed ECL cytosensor exhibits a satisfying performance in the practical application. Due to the anodic formation from a Mo metal substrate, the valuable feature is that the MoO xN y NTs-based ECL cytosensor can be used directly, thereby providing a stable and simplified ECL cytosensing platform for future clinical applications.

An electrochemiluminescence cytosensor for sensitive detection of HeLa cells based on a signal amplification strategy of Au-NaYF4:Yb,Er nanocomposites.

A novel electrochemiluminescence (ECL) cytosensor was proposed for the quantitative detection of HeLa cells (human cervical cancer cells) with the help of a signal amplification strategy. Firstly, the Au-NaYF4:Yb,Er nanocomposites were prepared by a simple in situ hydrothermal method and characterized by transmission electron microscopy (TEM) images, X-ray diffraction (XRD) patterns, UV-vis spectra and Fourier transform infrared (FTIR) spectra. Compared with the bare NaYF4:Yb,Er nanocomposites, the ECL intensity of Au-NaYF4:Yb,Er nanocomposites was greatly enhanced by about 4.2-fold which can be attributed to the good conductivity of gold nanoparticles (Au NPs). The nanocomposites showed high and stable ECL emission, fast response and superior conductivity, all of which were advantageous to the ECL detection. Furthermore, HeLa cells were immobilized on the modified electrode via the interaction between folic acid and a folate receptor present on the cell surface. The ECL cytosensor showed satisfactory sensitive response to HeLa cells in a linear range of 4.25 × 102-4.25 × 105 cells per mL with a low detection limit of 326 cells per mL. The proposed cytosensor had good sensitivity and stability, which can offer a great potential platform for bioassay analysis.

Label-free and dynamic evaluation of cell-surface epidermal growth factor receptor expression via an electrochemiluminescence cytosensor

A label-free electrochemiluminescence (ECL) cytosensor was developed for dynamically evaluating of epidermal growth factor receptor (EGFR) expression on MCF-7 cancer cells based on the specific recognition of epidermal growth factor (EGF) with its receptor (EGFR). EGF-cytosensor was fabricated by in-situ electro-polymerization of polyaniline as substrate, using CdS quantum dots (CdS QDs) as ECL probe and gold nanoparticles (AuNPs) as a carrier for loading of EGF. AuNPs and CdS QDs were jointly attached on polyaniline surface to provide a sensitive and stable sensing interface, as well as a simple and label-free mode for ECL assay. Electron microscopy, atomic force microscopy (AFM) and electrochemical methods were employed to characterize the multilayer construction process of the sensing interface. The proposed EGF-cytosensor exhibited excellent analytical performance for MCF-7 cancer cells, ranging from 12 to 1.2×106 cellsmL−1, with a low detection limit of 12 cellsmL−1. Also, it was successfully applied in evaluating EGFR expression of cells surface, which was stimulated by some inhibitors or activator, and the results were confirmed by using flow cytometry and laser scanning confocal microscopy analysis. The proposed ECL cytosensor has potential applications in monitoring the dynamic variation of receptor molecules expression on cell surfaces in response to external stimulation by drugs and screening anti-cancer therapeutic agents.

Ultrasensitive Cytosensor Based on Self-Enhanced Electrochemiluminescent Ruthenium-Silica Composite Nanoparticles for Efficient Drug Screening with Cell Apoptosis Monitoring.

The self-enhanced electrochemiluminescence (ECL) with high sensitivity could be an effective method for anticancer drug screening with cell apoptosis monitoring. Here we reported an ultrasensitive ECL cytosensor for cell apoptosis monitoring by using self-enhanced electrochemiluminescent ruthenium-silica composite nanoparticles (Ru-N-SiNPs) labeled annexin V as signal probes. The Ru-N-SiNPs were first synthesized through simple hydrolysis of a novel precursor containing luminescent and intracoreactant groups in one molecule, which presented higher emission efficiency and enhanced ECL intensity due to the shorter electron-transfer path and less energy loss. Moreover, the as-proposed ECL cytosensor was successfully used to investigate efficiency of paclitaxel toward MDA-MB-231 breast cancer cell in the range from 1 nM to 200 nM with a detection limit of 0.3 nM and a correlation coefficient of 0.9917. The improved accuracy and excellent dynamic range revealed the potential applications in biomolecules diagnostics and cells detections, especially in living and complex systems.

In situ electrochemical synthesis of Ni-capped electrochemiluminescence nanoprobe for ultrasensitive detection of cancer cells

A facile, novel and in situ electrochemical synthesis of a Ni-capped (NiS@CdS/PANINF) composite electrochemiluminescence (ECL) nanoprobe was developed to fabricate an ECL cytosensor for the ultrasensitive detection of cancer cells.

Enhanced iridium complex electrochemiluminescence cytosensing and dynamic evaluation of cell-surface carbohydrate expression.

A newly prepared [(ppy)2 Ir(dcbpy)](+) ⋅PF6 (-) (ppy: 2-phenylpyridyl; dcbpy: 4,4'-dicarboxy-2,2'-bipyridyl) and gold nanoparticle functionalized mesoporous silica nanoparticle (Au/Ir-MSN) is reported. Based on the binding between concanavalin A (Con A) and mannose, the novel nanoparticle was applied to an ultrasensitive electrochemiluminescence (ECL) in situ cytosensing strategy and the dynamic evaluation of cell-surface carbohydrate expression. The ECL activity of the presented Con A@Au/Ir-MSN nanoprobe was greatly enhanced by employing a functionalized nanoparticle and graphene nanomaterial with an increased surface area and simultaneously improved electron-transfer efficiency at the electrode interface. Under optimal conditions, the sandwich-type ECL cytosensor showed a linear response to K562 cells at concentrations ranging from 1.0×10(2) to 1.0×10(6) cells mL(-1) and realized a low detection limit of a single cell. The proposed method could also be successfully used for monitoring the dynamic variation of carbohydrate expression in cancer cells in response to external stimulation by an inhibitor.