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The abnormal variation of the mucin 1 (MUC1) protein level is associated with the development of multiple cancers, and the monitoring of trace MUC1 can be useful for early disease diagnosis. Here, on the basis of the synchronization of DNA-fueled sequence recycling and dual rolling circle amplification (RCA), the establishment of a non-label and highly sensitive fluorescent aptamer-based detection strategy for the MUC1 protein biomarker is described. The target MUC1 binds the aptamer hairpin probe and causes its structure switching to release an ssDNA tail to trigger the recycling of the complex via two toehold-mediated strand displacement reactions under assistance of a fuel DNA. Such a recycling amplification leads to the formation of a partial dsDNA duplex with two primers at both ends, which cooperatively bind the circular DNA ring template to start the dual RCA to produce many G-quadruplex sequences. The protoporphyrin IX dye further associates with the G-quadruplex structures to show a dramatically elevated fluorescent signal for sensitively detecting MUC1 with a low detection limit of 0.5 pM. The established aptamer-based detecting strategy is also highly selective and can realize assay of MUC1 in diluted human serums, highlighting its potential for the detection of different protein biomarkers at low contents. [ABSTRACT FROM AUTHOR]

MnV2O6 is a promising anode material for lithium ion batteries with high theoretical specific capacity, abundant reserves and inexpensive constituent elements. However, in the process of lithization and de-lithization, the MnV2O6 anode material will form an amorphous phase, leading to collapse of its original layered structure; this greatly decreases its lithium storage capacity and specific capacity and affects its long-term cycle performance. In this study, 2D accordion-like MnV2O6 nanosheets with Co-doping are obtained via a hydrothermal route. The cobalt ions partially replace the positions of the manganese ions, and the emergence of Co3+ ions is inferred to induce the formation of a built-in electric field in the electrode to enhance the electrochemical behaviour of MnV2O6, presenting a high capacity of 1005.9 mA h g−1 after hundreds of cycles. The capacitive contribution to the total capacity is investigated to obtain insight into the kinetic analysis of its electrochemical behaviour. This study sheds light on an effective strategy to obtain excellent electrochemical behavior of MnV2O6-based materials and other transition metal oxides as electrodes for lithium storage. [ABSTRACT FROM AUTHOR]

Detection of aberrant ATP concentrations with high sensitivity and selectivity is of critical importance for monitoring many biological processes and disease stages. By coupling extension/excision amplification with target recycling, we have established an aptamer-based method for label-free fluorescence ATP detection in human serum with high sensitivity. The ATP target molecules associate with the aptamer-containing double hairpin probes and cause conformational changes of the probes to initiate the cyclic strand extension/excision processes in the presence of polymerase, endonuclease and assistance sequences for the recycling of ATP and the production of a large number of G-quadruplex sequences. The organic dye thioflavin T subsequently binds these G-quadruplex sequences to yield substantially enhanced fluorescence emission for achieving highly sensitive detection of ATP down to 2.2 nM in the range of 5 to 200 nM without using any labels. The developed aptamer sensing method also exhibits high selectivity and allows the monitoring of ATP at low concentrations in diluted real samples, which offers promising opportunities to establish effective signal magnification means for the detection of various biomolecules at trace levels. [ABSTRACT FROM AUTHOR]

The presence of target microRNA triggers cascaded and catalytic self-assembly of two DNA motifs into DNA nanostructures, which serves as a remarkable signal amplification means for the highly sensitive monitoring of the target microRNA and the detection of low numbers of tumor cells. [ABSTRACT FROM AUTHOR]

Catalytic self-assembly of DNA nanostructures triggered by microRNA 21 (miR-21) is achieved through isothermal toe-hold strand displacement reactions. The miR-21 is autonomously recycled during the self-assembly process, which makes the generation of the DNA nanostructures proceed in a catalytic fashion. The miR-21-triggered self-assembly of DNA nanostructures can also serve as a remarkable signal amplification platform to achieve ultrasensitive detection of miR-21 from as low as 10 MCF-7 human breast cancer cells. [ABSTRACT FROM AUTHOR]

Chemically reduced Cu2+ triggers the ligation of alkynyl- and azido-modified DNA via click chemistry. Subsequently, the ligated DNA initiates cyclic assembly of two fluorescently quenched hairpin DNAs and generates significantly amplified fluorescence signals for highly sensitive detection of Cu2+ in human serum samples. [ABSTRACT FROM AUTHOR]

The presence of the microRNA-141 target molecules activates the DNA molecular machine powered by the DNA fuel strands, leading to non-enzymatic target cyclic reuse of microRNA-141 and significantly amplified fluorescent signals for sensitive monitoring of microRNA-141 from low numbers of human prostate cancer cells. [ABSTRACT FROM AUTHOR]

Positively charged gold nanoparticles ((+)AuNPs) are electrostatically adsorbed on the negatively charged aptamers and the solution displays a blue color due to the aggregation of the (+)AuNPs, while the binding of the target lysozyme with the aptamers reduces the charge of the aptamers, which stabilizes the (+)AuNPs and the (+)AuNPs solution remains red in color. [ABSTRACT FROM AUTHOR]

The abnormal variation of the mucin 1 (MUC1) protein level is associated with the development of multiple cancers, and the monitoring of trace MUC1 can be useful for early disease diagnosis. Here, on the basis of the synchronization of DNA-fueled sequence recycling and dual rolling circle amplification (RCA), the establishment of a non-label and highly sensitive fluorescent aptamer-based detection strategy for the MUC1 protein biomarker is described. The target MUC1 binds the aptamer hairpin probe and causes its structure switching to release an ssDNA tail to trigger the recycling of the complex via two toehold-mediated strand displacement reactions under assistance of a fuel DNA. Such a recycling amplification leads to the formation of a partial dsDNA duplex with two primers at both ends, which cooperatively bind the circular DNA ring template to start the dual RCA to produce many G-quadruplex sequences. The protoporphyrin IX dye further associates with the G-quadruplex structures to show a dramatically elevated fluorescent signal for sensitively detecting MUC1 with a low detection limit of 0.5 pM. The established aptamer-based detecting strategy is also highly selective and can realize assay of MUC1 in diluted human serums, highlighting its potential for the detection of different protein biomarkers at low contents.

MnV2O6 is a promising anode material for lithium ion batteries with high theoretical specific capacity, abundant reserves and inexpensive constituent elements. However, in the process of lithization and de-lithization, the MnV2O6 anode material will form an amorphous phase, leading to collapse of its original layered structure; this greatly decreases its lithium storage capacity and specific capacity and affects its long-term cycle performance. In this study, 2D accordion-like MnV2O6 nanosheets with Co-doping are obtained via a hydrothermal route. The cobalt ions partially replace the positions of the manganese ions, and the emergence of Co3+ ions is inferred to induce the formation of a built-in electric field in the electrode to enhance the electrochemical behaviour of MnV2O6, presenting a high capacity of 1005.9 mA h g-1 after hundreds of cycles. The capacitive contribution to the total capacity is investigated to obtain insight into the kinetic analysis of its electrochemical behaviour. This study sheds light on an effective strategy to obtain excellent electrochemical behavior of MnV2O6-based materials and other transition metal oxides as electrodes for lithium storage.

Chemically reduced Cu(2+) triggers the ligation of alkynyl- and azido-modified DNA via click chemistry. Subsequently, the ligated DNA initiates cyclic assembly of two fluorescently quenched hairpin DNAs and generates significantly amplified fluorescence signals for highly sensitive detection of Cu(2+) in human serum samples.