Search

Prostate specific antigen (PSA) has been considered as the most potential serological biomarker for the early stage detection of prostate cancer. Here, a label-free fluorescence aptasensing strategy for detecting PSA based on hybridization chain reaction (HCR) and G-quadruplex DNAzymes has been developed. This designed strategy consists of three DNA probes, aptamer probe (AP), hairpin probe 1 (H1) and hairpin probe 2 (H2). In the presence of target PSA, the aptamer sequences in AP specifically recognized PSA to form a PSA–aptamer complex, causing an AP conformation change and thus releasing the initiator, which triggered the chain-like assembly of H1 and H2 that yielded extended nicked double-stranded DNA through HCR. Upon the addition of hemin, the G-rich segments at the end of H1 and H2 self-assembled into the peroxidase-mimicking hemin/G-quadruplex DNAzymes, which catalyzed the hydrogen peroxide-mediated oxidation of thiamine to give a fluorescence signal dependent on the concentration of PSA. Under optimal conditions, a limit of detection of 0.05 nM and a linear range from 0.1 nM to 1 nM (R2 = 0.9942) were achieved by this assay. In addition, other interfering proteins, such as IgG, AFP and CEA, did not produce any significant change in the fluorescence intensity response, indicating good selectivity of this sensor for PSA detection. Finally, this proposed aptasensor was successfully used for diluted serum samples. [ABSTRACT FROM AUTHOR]

The key for the application of LiCoO2 as a lithium-ion battery electrode at high voltage is to suppress the irreversible phase transformation from the layered to the spinel/rocksalt structure during cycling. The experimental study (R. Zhao, J. Zhang, G.-H. Lee, K. Zhang, V. W.-H. Lau, J.-J. Lee, I. Moudrakovski, Y.-L. Yang, F. Zou, M. Park, I. M. Hung and Y.-M. Kang, J. Mater. Chem. A, 2020, 8, 12424) demonstrated that Sn doping into LiCoO2 effectively inhibits the undesired phase transition and ascribed the structural stability to the ability of the Sn dopant to pin the lattice thermal vibration. However, the detailed information on Sn-doped LiCoO2, such as atomic structures, still remains uncovered. Here, we carried out a comprehensive theoretical study on un-doped and Sn-doped LiCoO2 with the aid of first-principles calculations. Our study shows that the un-doped and Sn-doped systems investigated in the experiment should contain Co–O vacancies and Sn prefers to be doped at the site that is near to the Co–O vacancies. The study also demonstrates that Sn-doping can significantly decrease the variation in volume and inhibit Co migration during delithiation. Additionally, Sn-doping can reduce the average activation barrier of Li diffusion. The theoretical study gives an insight into the microscopic mechanism of Sn-doping to enhance the performance of LiCoO2 as a cathode material and is a necessary complement to the experimental study. [ABSTRACT FROM AUTHOR]

Herein, nanosized fumed silica (FS) with poor electrical conductivity is used as an "electron inhibitor" between Li metal and garnet solid electrolyte (SE) to prevent lithium dendrite growth. The FS demonstrated its effectiveness in preventing the fast lithium dendrite propagation during the long-term lithium stripping and plating processes, leading to an enhanced battery performance. We believe this study could help shed light on such electron inhibitors in constructing all-solid-state batteries (ASSBs) with superior cycling performance. [ABSTRACT FROM AUTHOR]

Herein, the coordination-induced increase in the electron density of fused C6 rings in MOFs as high performance anode materials for Li+ ion batteries is described. Zn-PTCA is able to deliver a high specific capacity of 700 mA h g−1 at 50 mA g−1 and exhibits excellent cycle performance over 1100 cycles and good rate capability. [ABSTRACT FROM AUTHOR]

Fe2O3/Fe3O4–S core–shell nanorods were fabricated on a carbon cloth by sulfurization of FeOOH and post annealing. The prepared electrode exhibited remarkable cyclic stability and attractive rate capability for lithium storage. [ABSTRACT FROM AUTHOR]

A novel catalytic enantioselective synthesis of functionalized 1,3-enynes has been developed featuring the design and synthesis of conjugated nitro dienynes as a useful new class of Michael acceptors. Moreover, a simple, yet flexible catalytic cascade approach to functionalized enantioenriched acyclic α,β-enones and cyclic dienones has also been developed. [ABSTRACT FROM AUTHOR]