Based on the multivalent binding capability of streptavidin (SA) to biotin, a multifunctional quantum dot probe (QD‐(AS‐ODN+p160)) coupled with antisense oligonucleotide (AS‐ODN) and peptide p160 is ...designed for real‐time tracking of targeted delivery of AS‐ODN and regulation of folate receptor‐α (hFR‐α) in MCF‐7 breast cancer cells. Fluorescence spectra, capillary electrophoresis (CE) and dynamic light scattering (DLS) are used to characterize the conjugation of AS‐ODN and p160 with quantum dots (QDs), DLS results confirm the well stability of the probe in aqueous media. Confocal imaging and quantitative flow cytometry show that QD‐(AS‐ODN+p160) is able to specifically target human breast cancer MCF‐7 cells. Low temperature and ATP depletion treatments reveal the cellular uptake of QD‐(AS‐ODN+p160) is energy‐dependent, and the effects of inhibition agents and co‐localization imaging further confirm the endocytic pathway is mainly receptor‐mediated. Transmission electron microscopy (TEM) shows the intracellular delivery and endosomal escape of QD probe along with incubation time extended. Two transfection concentrations of QD probe (10 nM and 50 nM) below half inhibitory concentration (IC50) value are chosen according to MTT assay. Real‐time PCR shows at these two concentration cases the relative mRNA expression levels of hFR‐α reduce to 72.5 ± 3.9% and 17.6 ± 1.0%, respectively. However, western blot and quantitative ELISA analysis show the expression level of hFR‐α protein has a significant decrease only at 50 nM, indicating that gene silence is concentration‐dependent. These results demonstrate that the QD‐(AS‐ODN+p160) probe not only achieves gene silence in a cell‐specific manner but also achieves real‐time tracking during AS‐ODN intracellular delivery.
A new multifunctional quantum dot (QD) probe is prepared by coupled with anti‐hFR‐α antisense oligonucleotide and targeted peptide p160 with QDs through biotin‐streptavidin interaction. Down‐regulation of hFR‐α in a cell‐specific manner is achieved. The probe is effectively transported into the cytoplasm through receptor‐mediated endocytosis, and finally antisense oligonucleotides combine with hFR‐α mRNA and block the protein translation.
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•A ratiometric ECL sensor was constructed using luminol as single luminophor.•The ECLanodic/ECLcathodic was independent with the coreactant H2O2 concentrations.•The ratiometric sensor ...showed superior sensitivity and accuracy than the single-signal sensors.•4. The proposed ECL sensor exhibited high sensitivity for CEA detection with a wide linear range and a low detection limit.
Ratiometric electrochemiluminescence (ECL) assays have attracted widespread attentions in biosensing owing to their precise measurements by eliminating the environmental interferences. However, they mostly needed two eligible luminophors, increasing the complexity of the systems and limiting their practical applications. Herein, using luminol as single luminophor, a dual-potential ratiometric ECL strategy was proposed to detect carcinoembryonic antigen (CEA). The luminol exhibited cathodic and anodic emissions on graphene-ionic liquid-platinum (GR-IL-Pt) composites and Ti3C2 MXenes-Au NPs hybrids, respectively. Then, a sandwich ECL sensor was fabricated using GR-IL-Pt composites as matrix to immobilize the primary antibodies of CEA and Ti3C2 MXenes-Au NPs hybrids as platform to load the secondary antibodies. With the presence of CEA, the ratio of anodic ECL to cathodic ECL (ECLanodic/ECLcathodic) increased obviously, realizing sensitive ratiometric detection of CEA. In addition, the ECLanodic/ECLcathodic was independent with the concentrations of H2O2, greatly improving the test reliability. The developed ECL sensor exhibited a sensitive detection toward CEA, performing a wide linearity in the range of 0.1 pg mL−1 - 10 ng mL−1 with a low detection limit of 34.58 fg mL-1 (S/N = 3). Furthermore, this strategy exhibited a good practicality to detect CEA in human serums, providing a promising strategy in ECL bioanalysis.
A novel ratiometric electrochemical biosensing strategy based on T7 exonuclease (T7 Exo)-assisted homogenous target recycling coupling hairpin assembly triggered dual-signal output was proposed for ...the accurate and sensitive detection of microRNA-141 (miRNA-141). Concretely, in the presence of target miRNA, abundant signal transduction probes were released via the T7 Exo-assisted homogenous target recycling amplification, which could be captured by the specially designed ferrocene-labeled hairpin probe (Fc-H1) on -electrode interface and triggered the nonenzymatic catalytic hairpin assembly (Fc-H1 + MB-H2) to realize the cascade signal amplification and dual-signal output. Through such a conformational change process, the electrochemical signal of Fc (IFc) and MB (IMB) is proportionally and substantially decreased and increased. Therefore, the signal ratio of IMB/IFc can be employed to accurately reflect the true level of original miRNA. Benefiting from the efficient integration of the T7 Exo-assisted target recycle, nonenzymatic hairpin assembly and dual-signal output mode, the proposed sensor could realize the amplified detection of miRNA-141 effectively with a wide detection range from 1 fM to 100 pM, and a detection limit of 200 aM. Furthermore, it exhibits outstanding sequence specificity to discriminate mismatched RNA, acceptable reproducibility and feasibility for real sample. This strategy effectively integrated the advantages of multiple amplification and ratiometric output modes, which could provide an accurate and efficient method in biosensing and clinical diagnosis.
Brominated flame-retardants (BFRs) are environmental endocrine disruptors, comprising several pollutants, which potentially affect the endocrine system and cause dysfunction and disease. Widespread ...BFR exposure may cause multisystem toxicity, including cardiovascular toxicity in some individuals. Studies have shown that BFRs not only increase heart rate, induce arrhythmia and cardiac hypertrophy, but also cause glycolipid metabolism disorders, vascular endothelial dysfunction, and inflammatory responses, all of which potentially induce pre-pathological changes in atherosclerosis. Experimental data indicated that BFRs disrupt gene expression or signaling pathways, which cause vascular endothelial dysfunction, lipid metabolism-related disease, inflammation, and possibly atherosclerosis. Considerable evidence now suggests that BFR exposure may be a pro-atherosclerotic risk factor. In this study, we reviewed putative BFR effects underpinning pro-atherosclerosis mechanisms, and focused on vascular endothelial cell dysfunction, abnormal lipid metabolism, pro-inflammatory cytokine production and foam cell formation. Consequently, we proposed a scientific basis for preventing atherosclerosis by BFRs and provided concepts for further research.
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•BFRs could induce pre-pathological changes in atherosclerosis.•BFRs cause vascular endothelial dysfunction, lipid metabolism-related disease and inflammation.•BFRs effects underpinning pro-atherosclerosis mechanisms.
Neutrophils are the first line of defense against pathogens. They are divided into multiple subpopulations during development and kill pathogens through various mechanisms. Neutrophils are considered ...one of the markers of severe COVID-19.
In-depth research has revealed that neutrophil subpopulations have multiple complex functions. Different subsets of neutrophils play an important role in the progression of COVID-19.
In this review, we provide a detailed overview of the developmental processes of neutrophils at different stages and their recruitment and activation after SARS-CoV-2 infection, aiming to elucidate the changes in neutrophil subpopulations, characteristics, and functions after infection and provide a reference for mechanistic research on neutrophil subpopulations in the context of SARS-CoV-2 infection. In addition, we have also summarized research progress on potential targeted drugs for neutrophil immunotherapy, hoping to provide information that aids the development of therapeutic drugs for the clinical treatment of critically ill COVID-19 patients.
It is important to design a nice electrochemiluminescence (ECL) biological nanomaterial for fabricating sensitive ECL immunosensor to detect tumor markers. Most reported ECL nanomaterial was ...decorated by a number of mono-luminophore. Here, we report a novel ECL nanomaterial assembled by dual luminophores perylenetetracarboxylic acid (PTCA) and carbon quantum dots (CQDs). In the ECL nanomaterial, graphene was chosen as nanocarrier. Significant ECL intensity increases are seen in the ECL nanomaterial, which was interpreted with the proposed synergistic promotion ECL meachanism of PTCA and CQDs. Furthermore, this ECL nanomaterial was used to label secondary antibody and fabricate a sandwiched carcinoembryonic antigen (CEA) immunosensor. The CEA immunosensor exhibits high sensitivity and the linear semilogarithmical range was from 0.001fgmL−1 to 1ngmL−1 with low detection limit 0.00026fgmL−1. And the CEA immunosensor is also suitable for various cancers’ sample detection providing potential specific applications in diagnostics.
•For designing ECL nanomaterial assembled by dual luminophores, perylenetetracarboxylic acid (PTCA) and carbon quantum dots (CQDs) were choosed as dual luminophores and graphene as nanocarrier.•Significant ECL intensity increases are seen in this novel ECL nanomaterial.•The synergistic promotion ECL meachanism of PTCA and CQDs is proposed.•The fabricated immunosensor based on this ECL nanomaterial shows sensitive ECL response for CEA detection and is suitable for cancers’ samples detection.
The adaptive immune response induced by SARS-CoV-2 plays a key role in the antiviral process and can protect the body from the threat of infection for a certain period of time. However, owing to the ...limitations of clinical studies, the antiviral mechanisms, protective thresholds, and persistence of the immune memory of adaptive immune responses remain unclear. This review summarizes existing research models for SARS-CoV-2 and elaborates on the advantages of animal models in simulating the clinical symptoms of COVID-19 in humans. In addition, we systematically summarize the research progress on the SARS-CoV-2 adaptive immune response and the remaining key issues, as well as the application and prospects of animal models in this field. This paper provides direction for in-depth analysis of the anti-SARS-CoV-2 mechanism of the adaptive immune response and lays the foundation for the development and application of vaccines and drugs.
The low-potential electrochemiluminescence (ECL) sensors based on cathodic light emission of luminol have caused more and more concerns due to their good stability and reproducibility. In this work, ...highly porous platinum (Pt) nanostructures on ionic liquid functionalized graphene film (GR-IL/pPt) were prepared as platform to construct a label-free ECL sensor for the detection of carcinoembryonic antigen (CEA). Due to their good biocompatibility, excellent electrocatalytic activity and highly porous structure, the as-prepared GR-IL/pPt composites benefited amplified cathodic ECL signal of luminol and high loading density of the CEA antibody. After CEA was incubated with the CEA antibody, the cathodic ECL signal of luminol decreased thanks to the less conductive immunocomplex. The proposed ECL immunosensor realized high sensitivity for CEA detection with a wide linear range from 0.001 fg mL−1 to 1 ng mL−1 and an extremely low detection limit of 0.0003 fg mL−1 (S/N = 3). Moreover, the sensor showed good specificity, stability and reproducibility, indicating that the provided strategy had a promising potential in clinical detection.
•An ECL immunosensor was constructed based on a strong cathodic ECL of luminol.•Highly porous Pt amplified the cathodic ECL of luminol and enhanced the loading amount of anti-CEA.•The developed ECL immunosensor exhibited an extremely low detection limitation and a wide linear range.
