Telomerase activity detection has attracted much attention concerning its importance for early cancer diagnosis. Here, we established a ratiometric electrochemical biosensor for telomerase detection based on CuS quantum dots (CuS QDs) dependent DNAzyme-regulated dual signals. The telomerase substrate probe was used as the linker to combine the DNA fabricated magnetic beads and CuS QDs. In this way, telomerase extended the substrate probe with repeated sequence to from hairpin structure, releasing CuS QDs as an input to DNAzyme modified electrode . DNAzyme was cleaved with high current of ferrocene (Fc) and low current of methylene blue (MB). On the basis of the obtained ratiometric signals, telomerase activity detection was achieved in the range of 1.0 × 10 −12 -1.0 × 10 −6 IU/L, with the limit of detection down to 2.75 × 10 −14 IU/L. Moreover, telomerase activity from HeLa extracts was also tested to verify the clinical application.
Interfacial layer is deemed as an efficient approach to align the energy level and reduce the carrier recombination at the interfaces. Therefore, for the first time, a facile yet effective method to enhance carrier transport by copper oxide quantum dots (CuO x QDs) interfacial layer in inverted perovskite solar cells (PSCs) is developed. The high mobility of CuO x QDs interfacial layer could boost the performance of PSCs by providing a better electrical carrier transport. Furthermore, the higher crystallinity of perovskite layer on CuO x QDs layer reduced the charge trap state densities, which leads to an increase in carrier recombination resistance. As a result, our inverted PSCs exhibit a power conversion efficiency (PCE) of 19.91%, a 14.6% increment compared with the PCE of a control device. Our finding demonstrates the promise of enhancing carrier transport by interfacial layer for high-performance PSCs and expands choice of interfacial layer materials in PSCs.
Kai Niu,Zicheng Zuo,Xianbo Lu,Lili Zou,Jiping Chen
There is an urgent need for developing electrochemical biosensor based on the acetylcholinesterase (AChE) inhibition to real-time analysis of organophosphorus pesticides (OPs), but it is suffered from the sluggish electrode kinetics and high oxidation potential toward signal species. Herein, a nanocomposite of ultrafine Cu quantum dots (QD) uniformly loaded on three-dimensional ultrathin graphdiyne (GDY) nanosheets (denoted as Cu@GDY) was synthesized via a one-step strategy, which showing high-density of active sites with persistent stability. Then an AChE biosensor based on Cu@GDY was fabricated to detect OPs, and the results revealed that the Cu@GDY nanocomposite can significantly amplifies electrochemical signal and reduces the oxidation potential for OPs. The strong interaction between active site of Cu@GDY and thiocholine signal species caused rapid analyte aggregation and decreased the reaction activation energy of thiocholine electro-oxidation. Benefiting from the excellent catalytic activity of Cu@GDY nanocomposite and reasonable regulation of enzyme inhibition kinetics , the biosensor achieved rapid and sensitive detection of OPs with a detection limit of 1 μg L −1 for paraoxon . Furthermore, the biosensor demonstrated great reproducibility, good stability and high recovery rate for OPs detection in real samples. Cu@GDY based sensor also displayed high catalytic activities and good selectivity to the non-enzymatic detection of glucose in alkaline medium . Cu@GDY offers a versatile and promising platform for sensors and biosensors featuring remarkably enhanced activity and stability, and can be applied to many other fields as desirable electrocatalyst .
Copper quantum dots embedded in sodium borosilicate glass matrix were fabricated and analyzed in terms of their structural, chemical, and optical properties. X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses revealed that copper quantum dots were in face-centered-cubic crystalline phase and in the metallic state. Size and distribution of the quantum dots were measured by transmission electron microscopy (TEM) as well as high-resolution transmission electron microscopy (HRTEM). The results showed spherical shape have formed uniformly in the glass, and the size of these quantum dots were range from 1.5 to 5 nm with the average particle size about 2.7 nm. The third-order nonlinear optical properties of copper quantum dots doped glass were investigated by using Z-scan technique at the wavelength of 800 nm with femtosecond Ti: sapphire laser radiation. The value of third-order optical nonlinear susceptibility χ (3) of the glass was estimated to be 2.41 × 10 −11 esu.
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