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1.
Soft Matter ; 20(8): 1869-1883, 2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38318759

RESUMEN

Active nematics are dense systems of rodlike particles that consume energy to drive motion at the level of the individual particles. They exist in natural systems like biological tissues and artificial materials such as suspensions of self-propelled colloidal particles or synthetic microswimmers. Active nematics have attracted significant attention in recent years due to their spectacular nonequilibrium collective spatiotemporal dynamics, which may enable applications in fields such as robotics, drug delivery, and materials science. The director field, which measures the direction and degree of alignment of the local nematic orientation, is a crucial characteristic of active nematics and is essential for studying topological defects. However, determining the director field is a significant challenge in many experimental systems. Although director fields can be derived from images of active nematics using traditional imaging processing methods, the accuracy of such methods is highly sensitive to the settings of the algorithms. These settings must be tuned from image to image due to experimental noise, intrinsic noise of the imaging technology, and perturbations caused by changes in experimental conditions. This sensitivity currently limits automatic analysis of active nematics. To address this, we developed a machine learning model for extracting reliable director fields from raw experimental images, which enables accurate analysis of topological defects. Application of the algorithm to experimental data demonstrates that the approach is robust and highly generalizable to experimental settings that are different from those in the training data. It could be a promising tool for investigating active nematics and may be generalized to other active matter systems.

2.
Soft Matter ; 20(36): 7246-7257, 2024 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-39225732

RESUMEN

Deep learning-based optical flow (DLOF) extracts features in adjacent video frames with deep convolutional neural networks. It uses those features to estimate the inter-frame motions of objects. We evaluate the ability of optical flow to quantify the spontaneous flows of microtubule (MT)-based active nematics under different labeling conditions, and compare its performance to particle image velocimetry (PIV). We obtain flow velocity ground truths either by performing semi-automated particle tracking on samples with sparsely labeled filaments, or from passive tracer beads. DLOF produces more accurate velocity fields than PIV for densely labeled samples. PIV cannot reliably distinguish contrast variations at high densities, particularly along the nematic director. DLOF overcomes this limitation. For sparsely labeled samples, DLOF and PIV produce comparable results, but DLOF gives higher-resolution fields. Our work establishes DLOF as a versatile tool for measuring fluid flows in a broad class of active, soft, and biophysical systems.

3.
Nano Lett ; 23(17): 8194-8202, 2023 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-37624651

RESUMEN

Optimizing the interatomic distance of dual sites to realize C-C bond breaking of ethanol is critical for the commercialization of direct ethanol fuel cells. Herein, the concept of holding long-range dual sites is proposed to weaken the reaction barrier of C-C cleavage during the ethanol oxidation reaction (EOR). The obtained long-range Rh-O-Pt dual sites achieve a high current density of 7.43 mA/cm2 toward EOR, which is 13.3 times that of Pt/C, as well as remarkable stability. Electrochemical in situ Fourier transform infrared spectroscopy indicates that long-range Rh-O-Pt dual sites can increase the selectivity of C1 products and suppress the generation of a CO intermediate. Theoretical calculations further disclose that redistribution of the surface-localized electron around Rh-O-Pt can promote direct oxidation of -OH, accelerating C-C bond cleavage. This work provides a promising strategy for designing oxygen-bridged long-range dual sites to tune the activity and selectivity of complicated catalytic reactions.

4.
Angew Chem Int Ed Engl ; 63(46): e202412785, 2024 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-39105415

RESUMEN

Electrocatalytic reduction of CO2 into C2 products of high economic value provides a promising strategy to realize resourceful CO2 utilization. Rational design and construct dual sites to realize the CO protonation and C-C coupling to unravel their structure-performance correlation is of great significance in catalysing electrochemical CO2 reduction reactions. Herein, Cu-Cu dual sites with different site distance coordinated by halogen at the first-shell are constructed and shows a higher intramolecular electron redispersion and coordination symmetry configurations. The long-range Cu-Cu (Cu-I-Cu) dual sites show an enhanced Faraday efficiency of C2 products, up to 74.1 %, and excellent stability. In addition, the linear relationships that the long-range Cu-Cu dual sites are accelerated to C2H4 generation and short-range Cu-Cu (Cu-Cl-Cu) dual sites are beneficial for C2H5OH formation are disclosed. In situ electrochemical attenuated total reflection surface enhanced infrared absorption spectroscopy, in situ Raman and theoretical calculations manifest that long-range Cu-Cu dual sites can weaken reaction energy barriers of CO hydrogenation and C-C coupling, as well as accelerating deoxygenation of *CH2CHO. This study uncovers the exploitation of site-distance-dependent electrochemical properties to steer the CO2 reduction pathway, as well as a potential generic tactic to target C2 synthesis by constructing the desired Cu-Cu dual sites.

5.
Angew Chem Int Ed Engl ; 61(12): e202115735, 2022 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-35001467

RESUMEN

Constructing monodispersed metal sites in heterocatalysis is an efficient strategy to boost their catalytic performance. Herein, a new strategy using monodispersed metal sites to tailor Pt-based nanocatalysts is addressed by engineering unconventional p-d orbital hybridization. Thus, monodispersed Ga on Pt3 Mn nanocrystals (Ga-O-Pt3 Mn) with high-indexed facets was constructed for the first time to drive ethanol electrooxidation reaction (EOR). Strikingly, the Ga-O-Pt3 Mn nanocatalyst shows an enhanced EOR performance with achieving 8.41 times of specific activity than that of Pt/C. The electrochemical in situ Fourier transform infrared spectroscopy results and theoretical calculations disclose that the Ga-O-Pt3 Mn nanocatalyst featuring an unconventional p-d orbital hybridization not only promote the C-C bond-breaking and rapid oxidation of -OH of ethanol, but also inhibit the generation of poisonous CO intermediate species. This work discloses a promising strategy to construct a novel nanocatalysts tailored by monodispersed metal site as efficient fuel cell catalysts.

6.
Anal Chem ; 93(38): 12981-12986, 2021 09 28.
Artículo en Inglés | MEDLINE | ID: mdl-34515473

RESUMEN

In this work, a DNA three-way junction (TWJ) with multiple recognition regions was intelligently engineered, which could be applied as an unconfined DNA walker with a rapid walking speed and high sensitivity for electrochemical detection of microRNA (miRNA-182-5p). Once the target miRNA was presented, the hairpins on TWJ could be successively opened to form an annular DNA walker, which could walk on the entire scope of the electrode surface without the confine for the length of DNA walker legs compared with the traditional DNA walker, greatly improving the walking efficiency. In addition, this DNA walker with multirecognition segments could obviously increase the local concentration of recognition sites, which significantly enhanced the detection speed and sensitivity. As a result, this proposed biosensor with annular DNA as a walker could dexterously achieve the ultrasensitive and fast detection of miRNA-182-5p from 0.1 fM to 1 nM with a detection limit of 31.13 aM. Meaningfully, this strategy explored an innovative path in the design of a new DNA walker nanostructure for accomplishing speedy and sensitive detection of biomarkers.


Asunto(s)
Técnicas Biosensibles , MicroARNs , ADN/genética , Técnicas Electroquímicas , Límite de Detección , MicroARNs/genética
7.
Anal Chem ; 91(9): 6127-6133, 2019 05 07.
Artículo en Inglés | MEDLINE | ID: mdl-30933497

RESUMEN

Here, a bifunctional DNAzyme nanodevice (BFDN) with two detection paths toward the same target was intelligently designed and applied to construct a ratiometric electrochemical biosensor for highly reliable and sensitive mercury ion (Hg2+) detection. In the presence of the target Hg2+, the T-Hg2+-T pair could actuate the preassembled DNA four-branched nanostructure (DNA-4B) without cleavage capability transform to the BFDN with strong cleavage capability for triggering two synchronous Hg2+ detection paths, including a "signal-off" path (1) that consisted of a cascade DNAzyme cleavage reaction to dramatically decrease the ferrocene (Fc) response and a "signal-on" path (2) that accomplished the capture of significant amounts of methylene blue (MB) on the electrode surface under the assistant of DNAzyme2 (D2) in BFDN. This strategy not only effectively avoided the false positive signal compared with traditional single paths, but also proposed a new ratiometric method to successfully circumvent the deficiency that existed in previous ratiometric electrochemical biosensors. As a result, the reliable and sensitive Hg2+ detection was achieved in the range from 0.1 pM to 200 nM with a detection limit of 23 fM. Above all, here, the assembly of the BFDN is ingeniously coupled with amplification strategy, paving a promising avenue to promote the performances of simple multifunctional DNA nanomachines and facilitate the corresponding development of DNA nanomachines in biosensor platform.


Asunto(s)
Técnicas Biosensibles , ADN Catalítico/química , Técnicas Electroquímicas , Mercurio/análisis , Nanoestructuras/química , Nanotecnología , ADN Catalítico/metabolismo , Iones/análisis
8.
Mol Cancer ; 17(1): 70, 2018 03 06.
Artículo en Inglés | MEDLINE | ID: mdl-29510731

RESUMEN

BACKGROUND: Breast cancer is the most common cancer among women worldwide and metastasis is the leading cause of death among patients with breast cancer. The transforming growth factor-ß (TGF-ß) pathway plays critical roles during breast cancer epithelial-mesenchymal transition (EMT) and metastasis. SMAD2, a positive regulator of TGF-ß signaling, promotes breast cancer metastasis through induction of EMT. METHODS: The expression of miR-190 and SMAD2 in breast cancer tissues, adjacent normal breast tissues and cell lines were determined by RT-qPCR. The protein expression levels and localization were analyzed by western blotting and immunofluorescence. ChIP and dual-luciferase report assays were used to validate the regulation of ZEB1-miR-190-SMAD2 axis. The effect of miR-190 on breast cancer progression was investigated both in vitro and in vivo. RESULTS: miR-190 down-regulation is required for TGF-ß-induced EMT. miR-190 suppresses breast cancer metastasis both in vitro and in vivo by targeting SMAD2. miR-190 expression is down-regulated and inversely correlates with SMAD2 in breast cancer samples, and its expression level was associated with outcome in patients with breast cancer. Furthermore, miR-190 is transcriptionally regulated by ZEB1. CONCLUSIONS: Our data uncover the ZEB1-miR-190-SMAD2 axis and provide a mechanism to explain the TGF-ß network in breast cancer metastasis.


Asunto(s)
Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Transición Epitelial-Mesenquimal/genética , Regulación Neoplásica de la Expresión Génica , MicroARNs/genética , Interferencia de ARN , Factor de Crecimiento Transformador beta/metabolismo , Regiones no Traducidas 3' , Animales , Neoplasias de la Mama/patología , Línea Celular Tumoral , Modelos Animales de Enfermedad , Regulación hacia Abajo , Transición Epitelial-Mesenquimal/efectos de los fármacos , Femenino , Humanos , Ratones , Modelos Biológicos , Metástasis de la Neoplasia , Estadificación de Neoplasias , Motivos de Nucleótidos , Regiones Promotoras Genéticas , Transducción de Señal , Proteína Smad2/genética , Factor de Crecimiento Transformador beta/farmacología , Ensayos Antitumor por Modelo de Xenoinjerto
9.
Biochem Biophys Res Commun ; 501(1): 48-54, 2018 06 18.
Artículo en Inglés | MEDLINE | ID: mdl-29678577

RESUMEN

Breast cancer is the most common cancer among women worldwide. Chemoresistance remains to be a considerable obstacle in breast cancer therapy and it is often involves dysregulation of a variety of microRNAs (miRNAs). miR-485-5p functions as a tumor suppressor in several types of human cancers. However, its role in breast cancer chemosensitivity have not been determined. In the present study, we demonstrated that overexpression of miR-485-5p suppresses breast cancer progression and enhances chemosensitivity both in vitro and in vivo. Further study demonstrated that miR-485-5p directly targeted the 3'-untranslated region of survivin and overexpression of survivin overcomes the miR-485-5p induced effects on breast cancer. In conclusion, our study identified that miR-485-5p suppresses cancer progression and enhances the chemosensitivity by targeting survivin. Targeting survivin by miR-485-5p may provide a potential approach to reverse chemosensitivity in breast cancer cells.


Asunto(s)
Neoplasias de la Mama/genética , Neoplasias de la Mama/terapia , Proteínas Inhibidoras de la Apoptosis/antagonistas & inhibidores , MicroARNs/genética , MicroARNs/uso terapéutico , Regiones no Traducidas 3' , Animales , Neoplasias de la Mama/metabolismo , Línea Celular Tumoral , Proliferación Celular/genética , Progresión de la Enfermedad , Resistencia a Antineoplásicos/genética , Femenino , Regulación Neoplásica de la Expresión Génica , Marcación de Gen , Genes Supresores de Tumor , Humanos , Proteínas Inhibidoras de la Apoptosis/genética , Proteínas Inhibidoras de la Apoptosis/metabolismo , Células MCF-7 , Ratones , Ratones SCID , Invasividad Neoplásica/genética , Survivin , Regulación hacia Arriba , Ensayos Antitumor por Modelo de Xenoinjerto
10.
Polymers (Basel) ; 16(13)2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-39000617

RESUMEN

Due to the specificity, high efficiency, and gentleness of enzyme catalysis, the industrial utilization of enzymes has attracted more and more attention. Immobilized enzymes can be recovered/recycled easily compared to their free forms. The primary benefit of immobilization is protection of the enzymes from harsh environmental conditions (e.g., elevated temperatures, extreme pH values, etc.). In this paper, catalase was successfully immobilized in a poly(aryl ether sulfone) carrier (PAES-C) with tunable pore structure as well as carboxylic acid side chains. Moreover, immobilization factors like temperature, time, and free-enzyme dosage were optimized to maximize the value of the carrier and enzyme. Compared with free enzyme, the immobilized-enzyme exhibited higher enzymatic activity (188.75 U g-1, at 30 °C and pH 7) and better thermal stability (at 60 °C). The adsorption capacity of enzyme protein per unit mass carrier was 4.685 mg. Hydrogen peroxide decomposition carried out in a continuous-flow reactor was selected as a model reaction to investigate the performance of immobilized catalase. Immobilized-enzymes showed a higher conversion rate (90% at 8 mL/min, 1 h and 0.2 g) compared to intermittent operation. In addition, PAES-C has been synthesized using dichlorodiphenyl sulfone and the renewable resource bisphenolic acid, which meets the requirements of green chemistry. These results suggest that PAES-C as a carrier for immobilized catalase could improve the catalytic activity and stability of catalase, simplify the separation of enzymes, and exhibit good stability and reusability.

11.
Adv Mater ; 36(32): e2402257, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38831681

RESUMEN

Ultralong carbon nanotubes (CNTs) are considered as promising candidates for many cutting-edge applications. However, restricted by the extremely low yields of ultralong CNTs, their practical applications can hardly be realized. Therefore, new methodologies shall be developed to boost the growth efficiency of ultralong CNTs and alleviate their areal density decay at the macroscale level. Herein, a facile, universal, and controllable method for the in situ synthesis of floating bimetallic catalysts (FBCs) is proposed to grow ultralong CNT arrays with high yields and uniformity. Ferrocene and metal acetylacetonates serve as catalyst precursors, affording the successful synthesis of a series of FBCs with controllable compositions. Among these FBCs, the optimized FeCu catalyst increases the areal density of ultralong CNT arrays to a record-breaking value of ≈8100 CNTs mm-1 and exhibits a lifetime 3.40 times longer than that of Fe, thus achieving both high yields and uniformity. A 30-centimeters-long and high-density ultralong CNT array is also successfully grown with the assistance of FeCu catalysts. As evidenced by this kinetic model and molecular dynamics simulations, the introduction of Cu into Fe can simultaneously improve the catalyst fluidity and decrease carbon solubility, and an optimal catalytic performance will be achieved by balancing this tradeoff.

12.
Nat Commun ; 15(1): 815, 2024 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-38280849

RESUMEN

Radiative cooling is a zero-energy technology that enables subambient cooling by emitting heat into outer space (~3 K) through the atmospheric transparent windows. However, existing designs typically focus only on the main atmospheric transparent window (8-13 µm) and ignore another window (16-25 µm), under-exploiting their cooling potential. Here, we show a dual-selective radiative cooling design based on a scalable thermal emitter, which exhibits selective emission in both atmospheric transparent windows and reflection in the remaining mid-infrared and solar wavebands. As a result, the dual-selective thermal emitter exhibits an ultrahigh subambient cooling capacity (~9 °C) under strong sunlight, surpassing existing typical thermal emitters (≥3 °C cooler) and commercial counterparts (as building materials). Furthermore, the dual-selective sample also exhibits high weather resistance and color compatibility, indicating a high practicality. This work provides a scalable and practical radiative cooling design for sustainable thermal management.

13.
Plants (Basel) ; 12(3)2023 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-36771681

RESUMEN

The conventional double cropping system of winter wheat and summer maize (WW-SUM) in the North China Plain (NCP) consumes a large amount of water and chemical fertilizer, threatening the sustainable development of agriculture in this region. This study was based on a three-year field experiment of different cropping systems (2H1Y-two harvests in one year; 3H2Y-three harvests in two years; and 1H1Y-one harvest in one year). The 2H1Y system had three irrigation-fertilization practices (FP-farmer's practice; RI-reduced input; and WQ-Wuqiao pattern in Wuqiao County, Hebei Province). A soil-crop system model (WHCNS-soil water heat carbon nitrogen simulator) was used to quantify the effects of different cropping systems on water and nitrogen use efficiencies (WUE and NUE, respectively), and to explore the trade-offs between crop yields and environmental impacts. The results showed that annual yield, water consumption, and the WUE of 2H1Y were higher than those of the 3H2Y and 1H1Y systems. However, local precipitation during the period of crop growth could only meet 65%, 76%, and 91% of total water consumption for the 2H1Y, 3H2Y and 1H1Y systems, respectively. Nearly 65% of irrigation water (groundwater) was used in the period of wheat growth that contributed to almost 40% of the annual yield. Among the three patterns of the 2H1Y system, the order of the WUE was 2H1Y_RI > 2H1Y_WQ > 2H1Y_FP. Compared to 2H1Y_FP, the total fertilizer N application rates in 2H1Y_WQ, 2H1Y_RI, and 3H2Y were reduced by 25%, 65%, and 74%, respectively. The 3H2Y system had the highest NUE of 34.3 kg kg-1, 54% greater than the 2H1Y_FP system (22.2 kg kg-1). Moreover, the 3H2Y system obviously reduced nitrate leaching and gaseous N loss when compared with the other two systems. The order of total N loss of different cropping systems was 2H1Y (261 kg N ha-1) > 1H1Y (78 kg N ha-1) > 3H2Y (70 kg N ha-1). Considering the agronomic and environmental effects as well as economic benefits, the 3H2Y cropping system with optimal irrigation and fertilization would be a promising cropping system in the NCP that could achieve the balance between crop yield and the sustainable use of groundwater and N fertilizer.

14.
Talanta ; 250: 123683, 2022 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-35777344

RESUMEN

Herein, driven by the need of highly-efficient DNAzyme-amplified detection strategy, a novel 3D DNAzyme motor was designed as a biosensor platform for realizing sensitive detection of target DNA. The 3D DNAzyme motor was composed of target-activated DNAzyme nanowires and substrates H1-Fc that co-immobilized on Au@Fe3O4 nanoparticles (Au@Fe3O4NPS) surface, possessing high local concentration of DNA reactants and shortened distance between DNAzyme and substrates for enhancing electrochemical signal. Compared with traditional DNAzyme-powered machines, the target-activated DNAzyme nanowires of 3D DNAzyme motor had greater flexibility and more powerful cleavage capability without troublesome sequence optimization, which overcame the space limitation and simultaneously interacted with adjacent and distant substrates H1-Fc to output a large amount of cleavage products with high signal response. Therefore, on account of the above-mentioned merits of nanoparticles localization DNA design and DNAzyme nanowires, the reported 3D DNAzyme motor ingeniously overcame many defects existing in traditional DNAzyme-amplified detection strategies such as low reactants concentration, limited flexibility of DNAzyme and small DNAzyme swing range, realizing the sensitive detection of target DNA with a detection limit of 1.7 fM ranging from 5 fM to 50 nM. Impressively, the 3D DNAzyme motor here presented a new strategy to achieve effective DNAzyme signal amplification and provided a reference for the assembly of various and functional 3D DNA machines in the future.


Asunto(s)
Técnicas Biosensibles , ADN Catalítico , Nanocables , ADN/análisis , Técnicas Electroquímicas , Límite de Detección
15.
16.
Biosens Bioelectron ; 149: 111848, 2020 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-31726271

RESUMEN

In this work, a novel DNA circle capture probe with multiple target recognition domains was designed to develop an electrochemical biosensor for ultrasensitive detection of microRNA-21 (miRNA-21) and miRNA-155 simultaneously. The DNA circle capture probe was anchored at the top of the tetrahedron DNA nanostructure (TDN) to simultaneously recognize miRNA-21 and miRNA-155 through multiple target recognition domains under the assistance of Helper strands, which could trigger mimetic proximity ligation assay (mPLA) for capturing the beacons ferrocene (Fc)-A1 and methylene blue (MB)-A2 to achieve multiple miRNAs detection. In this way, the local reaction concentration could be enhanced and avoid the interference of various capture probes compared with the traditional multiplexed electrochemical biosensor with the use of different capture probes, resulting in the significantly improvement of detection sensitivity. As a result, this proposed biosensor showed wide linearity ranging from 0.1 fM to 10 nM with detection limits of miRNA-21 and miRNA-155 as 18.9 aM and 39.6 aM respectively, which also could be applied in the simultaneously detection of miRNA-21 and miRNA-155 from cancer cell lysates. The present strategy paved a new path in the design of capture probes for achieving more efficient and sensitive multiple biomarkers detections and possessed the potential applications in clinical diagnostic of diseases.


Asunto(s)
Técnicas Biosensibles , MicroARNs/aislamiento & purificación , Neoplasias/diagnóstico , Sondas de ADN/química , Técnicas Electroquímicas , Humanos , Límite de Detección , MicroARNs/química , Neoplasias/genética
17.
Dalton Trans ; 49(40): 13999-14008, 2020 Oct 20.
Artículo en Inglés | MEDLINE | ID: mdl-33078804

RESUMEN

Modifying the surface active sites of Pt-based catalysts at the atomic level is of great significance to enhance the electrooxidation of methanol molecules. Herein, efficient active site assembly strategies are proposed, precisely, aimed at building high-performance electrocatalysts. Serving as proof-of-concept examples, both instances of Pt nanowires surface doping isolated Ru atoms (Ru/Pt NWs) and Ru nanoparticles supported on Pt nanowires (Ru@Pt NWs) are specially designed to optimize the catalytic performance of methanol oxidation reaction (MOR). The specific activity and mass activity of optimal Ru/Pt NWs can reach up to 3.93 mA cm-2 and 568.40 mA mg-1Pt, respectively, which is 1.53/1.94 times that of the Ru@Pt NWs and 2.03/2.59 times that of pure Pt NWs. Detailed studies on mechanism reveal that the Pt-Ru alloy can significantly improve the electron transfer kinetics of MOR, and activate more Pt atoms involved in the Langmuir-Hinshelwood (L-H) pathway compared with Ru@Pt NWs, all of which collectively accelerate the methanol oxidation. This surface engineering strategy via assembling active sites can reveal a promising method in the design of advanced Pt-based catalysts for direct methanol fuel cells.

18.
Chem Sci ; 11(1): 148-153, 2020 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-32110366

RESUMEN

Herein, by directly introducing mismatched reactant DNA, high-reactivity and high-threshold enzyme-free target recycling amplification (EFTRA) is explored. The developed high-efficiency EFTRA (HEEFTRA) was applied as a programmable DNA signal converter, possessing higher conversion efficiency than the traditional one with perfect complement owing to the more negative reaction standard free energy (ΔG). Once traces of input target miRNA interact with the mismatched reactant DNA, amounts of ferrocene (Fc)-labeled output DNA could be converted via the EFTRA. Impressively, the Fc-labeled output DNA could be easily captured by the DNA tetrahedron nanoprobes (DTNPs) on the electrode surface to form triplex-forming oligonucleotide (TFO) at pH = 7.0 for sensitive electrochemical signal generation and the DTNPs could be regenerated at pH = 10.0, from which the conversion efficiency (N) will be accurately obtained, benefiting the selection of suitable mismatched bases to obtain high-efficiency EFTRA (HEEFTRA). As a proof of concept, the HEEFTRA as an evolved DNA signal converter is successfully applied for the ultrasensitive detection of miRNA-21, which gives impetus to the design of other signal converters with excellent efficiency for ultimate applications in sensing analysis, clinical diagnosis, and other areas.

19.
Nanoscale ; 12(17): 9669-9679, 2020 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-32319487

RESUMEN

Construction of an efficient bifunctional electrocatalyst through a rational interface-engineering strategy to optimize the adsorption energy of H* and OH* species at the atomic/molecular level is of great importance for water splitting. Although conventional NiFe layered double hydroxide (LDH) shows excellent performance for alkaline oxygen evolution reactions (OERs), it shows extremely poor activity toward hydrogen evolution reactions (HERs) due to weak hydrogen adsorption and sluggish kinetics. In this work, integration of sub-nanoscale Ru species with NiFe LDH can dramatically enhance the adsorption energy of H* and improve their HER kinetics. Besides, benefitting from the desired potential-induced strategy, the Ru-NiFe LDH interfaces will convert to RuO2-NiFe(OOH)x interfaces to optimize the adsorption energy of OH* to meet the requirement of strengthening the OER performance. Strikingly, the Ru-NiFe LDH-F/NF sample (NF: Ni foam) shows an excellent OER and HER performance with an overpotential of 230.0 mV and 115.6 mV at a current density of 10 mA cm-2, respectively, as well as outstanding durability. The overall water splitting device was fabricated by using Ru/NiFe LDH-F/NF as both the HER and OER electrode with a potential of 1.53 V to achieve a current density of 10 mA cm-2. In addition, the theoretical calculations demonstrated that the Ru-NiFe LDH interfaces could optimize the adsorption energy of H* and OH*. This study provides a new insight into the development of highly efficient bifunctional electrocatalysts for water electrolysis.

20.
ACS Appl Mater Interfaces ; 10(30): 25213-25218, 2018 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-29979026

RESUMEN

In this work, the highly efficient target recycling-based netlike Y-shaped DNA (Y-DNA), which regulated the electrocatalysis of Fe3O4@CeO2-Pt nanoparticles (Fe3O4@CeO2-PtNPs) toward methylene blue (MB) for signal amplification, was developed to prepare a sensitive DNA biosensor for detecting the DNA associated with oral cancer. Specifically, with the help of highly efficient enzyme-assisted target recycling (EATR) amplification strategy, one target DNA input was converted to corresponding plenty of DNA strands S1-Fe3O4@CeO2-Pt and S2-MB output, which could be employed to interact with HP2 immobilized on the electrode surface to form stable netlike Y-DNA without any waste of recycling products. Meanwhile, the formation of netlike Y-DNA could regulate electrocatalytic efficiency of Fe3O4@CeO2-PtNPs, inducing the proximity of Fe3O4@CeO2-PtNPs to MB and significantly enhancing electrochemical signal. Further, the signal could also be amplified by Fe3O4@CeO2-PtNPs modified on the electrode surface. By virtue of this ingenious design, a novel netlike Y-DNA structure based on highly efficient EATR was simply constructed and successfully applied to an electrochemical DNA biosensor along with electrocatalysis of Fe3O4@CeO2-PtNPs, achieving the sensitive detection of target DNA ranging from 10 fM to 50 nM with a detection limit of 3.5 fM. Impressively, the biosensor here demonstrates an admirable method for regulating the electrocatalysis of NPs toward substrates to enhance signal, and we believe that this biosensor is a potential candidate for the sensitive detection of target DNA or other disease-related nucleic acids.


Asunto(s)
ADN/química , Técnicas Biosensibles , Catálisis , Técnicas Electroquímicas , Electrodos , Límite de Detección , Azul de Metileno
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