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1.
Biosens Bioelectron ; 197: 113806, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34808591

RESUMO

Photocathodic biosensor has great capability in anti-interference from reductive substances, however, the low signal intensity of photoactive species with inferior detection sensitivity restricts its wide application. In this work, the P3HT-PbS nanocomposites were synthesized as signal tags, by integrating with target-trigger generated hemin/G-quadruplex nanotail as bi-enhancer to significantly apmplify the photocurrent, an ultrasensitive photocathodic biosensor was proposed for detection of ß2-microglobulin (ß2-MG). Impressively, P3HT with cathode signal is an attractive polymer consisted of substantial thiophene groups with high absorption coefficient and mobility of photo-generated holes, which could anchor with the PbS dots as sensitizer, providing a high charge mobility and strong photosensitivity. More importantly, target-trigger generated hemin/G-quadruplexes could accept the electron from illuminated photoactive species through the conversion of Fe(III)/Fe(II) in hemin, effectively reducing charge recombination rate as well as accelerating the generation of electron acceptor O2 in the assistant of H2O2. Moreover, hemin/G-quadruplexes inherited the HRP mimicking catalytic capability that further improved the produce of plentiful O2. As a result, PEC cathode signal was significantly enhanced for sensitive analysis of ß2-MG protein with a good detection range of 0.1 pg/mL to 100 ng/mL. It would provide a path for establishing PEC platform with excellent anti-interference ability and extend the application of photoelectrochemical (PEC) biosensor in bioanalysis and early disease diagnosis.

2.
Anal Chem ; 93(41): 13952-13959, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34613709

RESUMO

Herein, we designed a dual 3D DNA nanomachine (DDNM)-mediated catalytic hairpin assembly (DDNM-CHA) to construct an electrochemical biosensor for ultrasensitive detection of miRNA, which possesses quite a faster reaction rate and much higher amplification efficiency than those of traditional catalytic hairpin assembly (CHA). Impressively, since the DDNM skillfully increases the local concentration of reactants and decreases the steric hindrance of substrates simultaneously, the DDNM-CHA could be endowed with higher collision efficiency and more effective reaction compared with traditional CHA, resulting in a hyper conversion efficiency up to 2.78 × 107 only in 25 min. This way, the developed DDNM-CHA could easily conquer the main predicaments: long reaction time and low efficiency. As a proof of the concept, we adopt the gold nanoparticles (AuNPs) and the magnetic nanoparticle (Fe3O4) as the kernel of DNM-A and DNM-B, respectively, and harness the magnetic electrode to directly adsorb the products H1-H2/Fe3O4 for constructing an immobilization-free biosensor for high-speed and ultrasensitive detection of miRNA with a detection limit of 0.14 fM. As a result, the DDNM-CHA we developed carves out a new insight to design a functional DNA nanomachine and evolve the analysis method for practical amplification in the sensing area and promotes the deeper exploration of the nucleic acid signal amplification strategy and DNA nanobiotechnology.


Assuntos
Técnicas Biossensoriais , DNA Catalítico , Nanopartículas Metálicas , MicroRNAs , DNA , Técnicas Eletroquímicas , Ouro , Limite de Detecção
3.
Anal Chem ; 93(39): 13334-13341, 2021 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-34553919

RESUMO

Herein, a versatile ECL biosensor was fabricated for ultrasensitive detection of microRNA-21 (miRNA-21) from cancer cells based on a novel H2O2-free electrochemiluminescence (ECL) system (luminol/dissolved oxygen/Fe@Fe2O3 nanowires). Compared with the previously reported coreaction accelerator that needed a negative potential to produce reactive oxygen species (ROS), these newly discovered Fe@Fe2O3 nanowires could generate ROS in the detection solution immediately without the application of voltage, which narrowed down the detection potential range to avoid side reactions, favoring their practical application in biological systems. Especially, the Fe@Fe2O3 nanowires could produce H• for activating dissolved oxygen into ROS to improve the ECL intensity dramatically, which initiates a novel pathway to promote the generation of ROS for the ECL system. In addition, an original strand displacement amplification coupled with strand displacement reaction (SDA-SDR) was developed to improve the conversion efficiency of the target for sensitive detection of miRNA-21. By virtue of the SDR, a quadruple quenching effect was achieved through each output DNA strand of SDA; hence, the nucleic acid signal amplification efficiency was effectively enhanced. As expected, on account of the superb activation performance of Fe@Fe2O3 nanowires and the outstanding amplification efficiency of the SDR-SDA strategy, the fabricated ECL biosensor realized ultrasensitive detection of miRNA-21 with a detection limit down to 52.5 aM. The established ECL sensing platform ushered a new route for H2O2-free detection and a promising biomarker assay method for clinical diagnosis.


Assuntos
MicroRNAs , Nanofios , Luminol , Oxigênio
4.
Anal Chem ; 93(27): 9568-9574, 2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34210120

RESUMO

In this work, an original rolling-circle strand displacement amplification (RC-SDA) was developed by introducing a circle DNA with two recognition domains as a template instead of the limited liner DNA template in traditional strand displacement amplification (SDA), which displayed much shorter reaction time down to 30 min and quite higher conversion efficiency of more than 1.77 × 108 compared with those of traditional strand displacement amplification (SDA) and could be applied to construct a label-free biosensor for ultrasensitive detection of an HIV DNA fragment. Once the target HIV DNA fragment interacts with the template circle DNA, the RC-SDA could be activated to dramatically output amounts of mimic target DNA with the assistance of the Phi29 DNA polymerase and Nb.BbvCI enzyme. In application, while the output products were captured by the DNA tetrahedral nanoprobe (DTNP) modified electrode, the electrochemical tag silver nanoclusters (AgNCs) on DTNP would be released from the electrode surface, accompanied with an obviously decreased electrochemical signal. This way, the developed signal-off biosensor was successfully applied to realize the rapid and ultrasensitive detection of target HIV DNA fragment with a detection limit down to 0.21 fM, which exploits the new generation of a universal strategy beyond the traditional ones for applications in biosensing assay, clinic diagnosis, and DNA nanobiotechnology.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , DNA/genética , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico , Prata
5.
Anal Chem ; 93(31): 10890-10897, 2021 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-34313108

RESUMO

Organic materials with diverse structures and brilliant glowing colors have been attracting extensive attention in optical electronic devices and electrochemiluminescence (ECL) fields and are currently faced with the issue of low ECL efficiency. Herein, a series of tetraphenyl alkene nanocrystals (TPA NCs) with an ordered molecular structure were synthesized to explore regularities in the crystallization-induced enhanced (CIE) ECL emission effects by altering the number and position of vinyl on the backbone of TPA molecules. Among those TPA NCs, tetraphenyl-1,3-butadiene (TPB) NCs exhibit the brightest ECL emission via a coreactant pathway, with the relative ECL efficiency of up to 31.53% versus the standard [Ru(bpy)3]2+/TEA system, which is thousands of times higher than that of free TPB molecules. The high ECL efficiency of TPB NCs originates from the effective electron transfer of unique J-aggregates on the a axis of the nanocrystals to notably promote radiative transition and the restriction on the free rotation of TPB molecules to further suppress the nonradiative transition, which has exhibited great potential in ultrasensitive biosensing, efficient light-emitting devices, and clear ECL imaging fields. As a proof of concept, since dopamine (DA) can form benzoquinone species by electrochemical oxidation to realize intermediate radical quenching and excited-state quenching on the TPB NCs/TEA system, the TPB NCs with the CIE ECL effect are used to construct an ultrasensitive ECL-sensing platform for the determination of DA with a lower detection limit of 3.1 nM.


Assuntos
Técnicas Biossensoriais , Nanopartículas , Alcenos , Cristalização , Técnicas Eletroquímicas , Medições Luminescentes
6.
Anal Chem ; 93(31): 11019-11024, 2021 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-34324804

RESUMO

Au nanoparticles (Au NPs) can be self-assembled in a bottom-up orderly manner at the oil-water interface, which is widely used as SERS platforms, but the stability of the Au NP interface needs to be improved due to shaking or shifting and the Brownian motion. The DNA structure with unique sequence specificity, excellent programmability, and flexible end-group modification capability owns good potential to precisely control the plasmonic structure's distance. In this study, a large area of the SERS substrate is obtained from the DNA structure-stabilized self-assembled ordered Au NPs on the cyclohexane-water interface. Combining with the exonuclease III (exo III)-assisted DNA recycling amplification strategy, we construct a liquid-phase SERS biosensor for efficient detection of microRNA 155 (miRNA 155). Compared with the traditional randomly assembled Au NPs on the two-phase interface, the SERS signal is significantly enhanced and more stable. The detection limit of the SERS biosensor for miRNA 155 reached 1.45 fmol/L, which has a very wide linear range (100 fmol/L-5 nmol/L). This work gives an efficient approach to stabilize the self-assembly Au NPs on the liquid-liquid interface, which can broaden the application of SERS analysis.


Assuntos
Nanopartículas Metálicas , MicroRNAs , DNA , Ouro , Análise Espectral Raman
7.
Biosens Bioelectron ; 181: 113162, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33740541

RESUMO

Herein, a sensitive label-free photoelectrochemical (PEC) aptasensor was constructed for C-reactive protein (CRP) analysis based on a novel and efficient poly{4,8-bis[5-(2-ethylhexyl) thiophen-2-yl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl] thieno[3,4-b]-thiophene-4,6-diyl} (PTB7-Th)/H2O2 system with unexpected photoelectric performance. The proposed PTB7-Th/H2O2 system without any sensitizer could surmount defect of the poor photoelectric conversion efficiency of PTB7-Th, leading to the unexpected 10-fold photocurrent enhancement compared to the common PTB7-Th/PBS system. The strong enhancement effect might originate from the special function of hydrogen peroxide (H2O2) towards PTB7-Th. On the one hand, H2O2 as electron acceptor could continuously capture photogenerated electrons located at acceptor part of PTB7-Th, which would visibly improve the charge separation efficiency of PTB7-Th and the electron-receiving property of electrolyte solution, thus leading to the obviously enhanced photoelectric conversion efficiency (PCE). More importantly, H2O2 as oxidant could oxidize PTB7-Th to obtain oxidation product of PTB7-Th (OPP) with carbonyl group and carboxyl group, and the electron cloud density in donor part of the OPP was higher than that of PTB7-Th, therefrom producing the stronger electron-donating property and higher photoelectrochemical (PEC) reaction efficiency. As a proof of concept, the proposed PTB7-Th/H2O2 system was successfully applied in the construction of a label-free PEC aptasensor for sensitive analysis of CRP, which performed a wide detection range from 1 pM to 1000 nM with a low detection limit of 0.33 pM. This study demonstrated a novel approach to the rational design of photoelectric conversion system with high PEC performance and provided an inspired tack for the construction of high-efficiency photoelectric devices.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Proteína C-Reativa , Peróxido de Hidrogênio , Tiofenos
8.
Biosens Bioelectron ; 182: 113178, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33773379

RESUMO

DNA-based amplifiers with high programmability and accurate molecular recognition ability have become a versatile platform for target amplification. However, the random diffusion of capture probes (CPs) in most DNA amplifiers limits the target recognition efficiency, affecting the limit of detection. Herein, a high-efficient DNA amplifier was developed by localizing the CPs consisted of the unique palindromic tails and target recognition sequences on Au nanoparticle modified magnetic beads (Au@MBs). In the presence of target K-ras gene, the CPs with high local concentration and orientation could capture the target efficiently to expose their palindromic tails, which could act as primers to trigger the polymerization for target recycling. More importantly, the polymerization products could involve in the next recycle and produce abundant mimic targets (MTs) continuously, thereby achieving the detection of trace K-ras gene. Meanwhile, a novel electrochemiluminescence (ECL) indicator of a thin-layer of perylene (Pe) molecules decorated Ag microflowers (Pe@Ag MFs) was obtained based on the reaction between the perylene cation radical (Pe•+) and Ag atoms. The obtained Pe@Ag MFs exhibited desirable ECL performance because (i) a thin-layer of Pe molecules could reduce the inner filter effect and inactive emitters, (ii) the Ag MFs as coreaction accelerator could react with S2O82- to produce more SO4•- and shorten the distance between Pe•- and SO4•- to significantly enhance the ECL intensity of Pe with less energy loss. This work paves the way for the development of efficient amplification strategy and offers a paradigm for the preparation of high-efficiency ECL indicators.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Perileno , DNA , Técnicas Eletroquímicas , Ouro , Limite de Detecção , Medições Luminescentes , Prata
9.
Anal Chem ; 93(7): 3445-3451, 2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33570928

RESUMO

Ligand-protected gold nanoclusters (Au NCs) are promising electrochemiluminescence (ECL) emitters because of their striking optical properties and excellent biocompatibility, but free vibration and rotation of their ligand result in low ECL efficiency, dramatically limiting their applications. Herein, using the ligand of Au NCs as one of the building units, a Au NC-based metal-organic framework (Au NC-based MOF) was constructed by the coordination-assisted self-assembly strategy, which not only impedes the ligand rotation-induced energy dissipation but also diminishes the self-quenching effect due to the spatial distribution of Au NCs. As a proof of concept, the prepared GSH-Au NCs@ZIF-8 gives rise to a 10-fold enhanced anodic ECL efficiency compared to that of densely aggregated GSH-Au NCs with triethylamine as the coreactant. Based on high ECL efficiency of GSH-Au NCs@ZIF-8, a "signal off" sensing platform was proposed with rutin as a model analyte, achieving a low detection limit of 10 nM. Therefore, the strategy paves an effective and alternative methodology to enhance ECL efficiency of metal NCs, considerably broadening their potential applications in sensing analysis, clinical diagnosis, and light-emitting devices.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Estruturas Metalorgânicas , Técnicas Eletroquímicas , Ouro , Medições Luminescentes , Rutina
10.
Biosens Bioelectron ; 175: 112848, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33257184

RESUMO

Herein, we present a target-triggered bidirectional one-dimensional (1D) DNA walking nanomachine, built from a well-designed track, which could simultaneously move two different DNA walkers to the opposite direction along the track and release payload. This track is composed of a DNA walker station (chain S3) in the middle of track for storing two kinds of DNA walker (W1 and W2), and corresponding two kinds of payload conjugated DNA stators (chain S1, S2 and S4, S5) for the moving of walker on the two flanks of chain S3 respectively. Moreover, the chain S3 also serves as a target-assisted amplification platform based on a catalytic hairpin assembly (CHA)-like strategy. In the presence of target (nucleic acid), the dynamic assembly between hairpin (HP) and S3 is triggered for multiple recycling of target and releasing of W1 and W2. Since the W1 and W2 respectively correspond to 8-17 DNAzyme and 10-23 DNAzyme, they could cleave the RNA substrates with sequence specificity to move towards two opposite directions along the track at the same time, accompanying the release of payloads. Such a 1D DNA walking nanomachine is not only could propel the walker to move in two directions respectively but also improve the locomotion efficiency compared to the traditional single-directional 1D DNA walking nanomachine with the same amounts of stators. This concept of inducing the locomotion manner change on a 1D DNA device may provide a thought to facilitate the development of DNA dynamic nanomachines and intelligent nanosensors.


Assuntos
Técnicas Biossensoriais , DNA Catalítico , Nanopartículas Metálicas , DNA , Ouro
11.
Anal Chem ; 93(2): 1120-1125, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33295754

RESUMO

Metal nanoclusters (NCs) have attracted extensive interest in electrochemiluminescence (ECL) field, but it is still a significant challenge to prepare high ECL efficiency NCs, which tremendously precludes their application in sensing and imaging. Herein, we report poly(3,4-ethylenedioxythiophene) (PEDOT) as a functional ligand for NCs with a "kill three birds with one stone" role, acting as a stabilizer like existing templates, excitingly, excellent electrical conductivity to accelerate the injection of interfacial electrons, and outstanding electrocatalytic activity toward coreactants (S2O82-), which breaks the convention that traditional ligands act as a double-edged sword in ECL field. As an illustration, PEDOT-hosted Ag NCs were prepared with an unprecedented ECL intensity with S2O82- as a cathodic coreactant, which indicates that this novel ligand strategy will bring exciting opportunities, not only in opening up new horizons for rational development of high ECL efficiency metal NCs but also in advancing their potential applications in light-emitting devices and clinical biosensing. As a proof of concept, the PEDOT-hosted Ag NCs were applied as neoteric ECL emitters to achieve sensitive detection of dopamine (DA), which showcased a wide linear response from 1 nM to 10 mM and a low detection limit of 0.17 nM.


Assuntos
Técnicas Biossensoriais , Compostos Bicíclicos Heterocíclicos com Pontes/química , Dopamina/análise , Técnicas Eletroquímicas , Medições Luminescentes , Polímeros/química , Compostos de Sódio/química , Sulfatos/química , Eletrodos , Nanopartículas Metálicas/química , Tamanho da Partícula , Prata/química , Propriedades de Superfície
12.
Biosens Bioelectron ; 173: 112820, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33227674

RESUMO

Developing low-cost and efficient methods to enhance the electrochemiluminescence (ECL) intensity of luminophores is highly desirable and challenging. Herein, we develop a synergistic promotion strategy based on three types of co-reaction accelerators to achieve an efficient SnO2 quantum dots (SnO2 QDs)-based ternary ECL system. Specifically, the MnO2 nanoflowers (MnO2 NFs), Ag nanoparticles (Ag NPs) and hemin/G-quadruplex were rationally selected as co-reaction accelerators. Owing to the synergistic effect, the deft integration of three types of co-reaction accelerators enabled better structural stability, more exposed catalytic active sites, and faster charge transfer, thus more effectively facilitating the reduction of co-reactant (S2O82-) compared with that of the single co-reaction accelerator. To demonstrate the practical utility of this principle, an "on-off-super on" ECL biosensor was constructed in combination with a 3D DNA walker, which showed a superior linear range (10 aM-100 pM) and a low detection limit (2.9 aM) for the highly-sensitive miRNA-21 detection. In general, this work firstly reported that three types of co-reaction accelerators were deftly integrated to remarkably amplify the ECL emission of SnO2 QDs, and provided brand-new perspectives for research on the ingenious design of the structure and component of highly efficient co-reaction accelerators.

13.
Biosens Bioelectron ; 173: 112802, 2020 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-33220534

RESUMO

Traditional approaches for nucleic acids detection require prior amplification of target genes, while nanomaterials-aided DNA biosensors are very magnificent but still suffer from the nanomaterial acquirement and limited sensitivity (above picomolar level). Herein, fullerenol C60(OH)25, a representative fullerene derivative, was employed as a photoelectrochemical (PEC) nanoprobe to achieve discrimination and ultrasensitive detection of amplification-free single-stranded DNA (ssDNA) down to sub-femtomolar level. The bonded hydroxyl groups with intense density endowed fullerenol to directly recognize and capture ssDNA-AuNPs via the hydrogen bonding interactions (H-bonds), leading to a sharply decreased photocurrent with quenching efficiency up to 85%, which could be attributed to the photo-generated electrons on the conduction band of fullerenol (-4.66 eV) preferentially migrating to the Fermi level of AuNPs (-5.1 eV) rather than the electrode. In the presence of target gene (mutant human p53 gene fragment), the H-bonds between fullerenol and ssDNA were competitively depleted during the base pairing process of complete hybridization between ssDNA and target, making double-stranded DNA-AuNPs (dsDNA-AuNPs) depart so that the photocurrent powerfully recovered. On basis of the photocurrent variation before and after target introduction, this proposed simple, rapid and ultrasensitive PEC biosensor for amplification-free target gene detection illustrated a wide liner ranged from 1 fM to 100 pM and a detection limit of 0.338 fM. This work presented an ingenious strategy for the discrimination and ultrasensitive detection of nucleic acids, and the well-designed PEC biosensor was further conducive to the impetus of clinic diagnostics.

14.
Anal Chem ; 92(21): 14723-14729, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-33054154

RESUMO

Herein, the boron radical active sites of boron carbon oxynitride quantum dots (BCNO QDs) are electrically excited to produce boron radicals (B•) for catalyzing peroxydisulfate (S2O82-) as a coreactant to accelerate the generation of abundant sulfate radicals (SO4•-) for significant enhancement in the electrochemiluminescence (ECL) efficiency of BCNO QDs, which overcome the defect of traditional carbon-based QDs with low ECL efficiency. Impressively, under extremely low concentration of S2O82- solution, the BCNO QDs/S2O82- system could exhibit high ECL emission, realizing environmental friendliness and excellent biocompatibility for sensitive bioanalysis. As a proof-of-concept, BCNO QDs, a new generation of ECL emitters with high ECL efficiency, were successfully used in the ultrasensitive determination of microRNA-21, which pushes the exploration of new ECL emitters and broadens the application in the field of clinical diagnosis, ECL imaging, and molecular devices.


Assuntos
Compostos de Boro/química , Limite de Detecção , Medições Luminescentes/métodos , MicroRNAs/análise , Pontos Quânticos/química , Catálise , Eletroquímica , MicroRNAs/química
15.
Anal Chem ; 92(21): 14550-14557, 2020 11 03.
Artigo em Inglês | MEDLINE | ID: mdl-32985185

RESUMO

Herein, a novel single-enzyme-assisted dual recycle amplification strategy based on T7 exonuclease (T7 Exo) and a strand-displacement reaction (SDR) was designed to fabricate a photoelectrochemical (PEC) biosensor for sensitive microRNA-141 (miRNA-141) detection with the use of laminar bismuth tungstate (Bi2WO6) as photoactive material. Compared with a traditional enzyme-assisted dual recycle amplification strategy, the presented method could effectively refrain the enzyme interference reaction, reduce environmental sensitivity, and save cost. Here, hairpin DNA1 (H1) decorated on magnetic beads (MB) hybridized with target miRNA-141 to form an H1/miRNA-141 heteroduplex. With the introduction of hairpin DNA2 (H2)-labeled SiO2 (H2-SiO2), SDR was triggered between H2-SiO2 and H1, thus miRNA-141 was displaced from the H1/miRNA-141 heteroduplex and an H1/H2-SiO2 duplex was formed, realizing the reuse of the target. In the presence of T7 Exo, the H1/H2-SiO2 duplex was digested with the release of output DNA-SiO2. To enhance the target conversion rate, H1-MB was intactly released and cycled, which could initiate more T7 Exo digestion and free abundant output DNA-SiO2. Through such a process, a tiny miRNA-141 could induce substantial output DNA-SiO2, effectively improving the target amplification efficiency and detection sensitivity of a PEC biosensor. Furthermore, Bi2WO6 was modified on an electrode to provide a superior initial PEC signal due to its excellent electronic transformation capacity. With the introduction of output DNA-SiO2, the hairpin structure of H3 on the electrode was opened, making SiO2 close to the electrode surface, which significantly decreases the PEC signal. This work first established the PEC biosensor featuring a single-enzyme-assisted dual recycle amplification process for sensitive detection of biomarkers.


Assuntos
Técnicas Biossensoriais/métodos , Enzimas/metabolismo , Limite de Detecção , MicroRNAs/análise , Processos Fotoquímicos , DNA/química , DNA/genética , Eletroquímica , Eletrodos , Sequências Repetidas Invertidas , Imãs/química , MicroRNAs/química , Microesferas , Dióxido de Silício/química
16.
Anal Chem ; 92(19): 13581-13587, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32893627

RESUMO

Copper nanoclusters (Cu NCs) as emerging luminescent metal NCs are gaining increasing attention owing to the comparatively low cost and high abundance of the Cu element in nature. However, it remains challenging to manipulate the optical properties of Cu NCs. Unlike most dispersed Cu NCs, whose luminescence efficiency was restricted by nonexcited relaxation, the Cu NCs confined in a porous poly-l-cysteine (poly-l-Cys) film were generated controllably with enhanced electrochemiluminescence (ECL) by in situ electrochemical reduction. Specifically, poly-l-Cys provided a porous structure to regulate the generation of Cu NCs within its holes, which not only increased the restriction on the intramolecular vibration and rotation of the ligands but also expedited the electron transfer near the electrode surface, reflecting in an enhancement of the ECL signal and efficiency. As an application of the confined Cu NCs, an ECL biosensor with high performance was constructed skillfully for highly sensitive detection of alkaline phosphatase (ALP), which adopted Cu NCs as the ECL luminophore and poly-l-Cys as a coreaction accelerator in a novel ECL ternary system (Cu NCs/S2O82-/poly-l-Cys). Furthermore, an ingenious target amplification based on the combination of a DNA walker and click chemistry was developed to convert ALP to DNA strands efficiently, achieving great improvement in the recognition efficiency. As a result, the biosensor had a low detection limit (9.5 × 10-7 U·L-1) and a wide linear range (10-8-10-2 U·L-1) for ALP detection, which showed great promise for the detection of non-nucleic acid targets and the diagnosis of diseases.


Assuntos
Fosfatase Alcalina/sangue , Técnicas Biossensoriais , Técnicas Eletroquímicas , Medições Luminescentes , Nanopartículas Metálicas/química , Peptídeos/química , Fosfatase Alcalina/metabolismo , Cobre/química , Humanos , Tamanho da Partícula , Porosidade , Propriedades de Superfície
17.
Chem Commun (Camb) ; 56(70): 10215-10218, 2020 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-32748935

RESUMO

In this work, a novel DNA nanostructure with a shorter assembly time and larger loading capacity was constructed using amphiphilic DNA-alkane group (Spacer C12)10 conjugates encapsulating plentiful fat-soluble fluorescent dyes into the hydrophobic core to form the DNA micelles, which could be rapidly self-disassembled via target induced hydrophilic-hydrophobic regulation to release fluorescent dyes from micelles to the organic phase, realizing the fast and sensitive detection of microRNA.


Assuntos
Técnicas Biossensoriais/métodos , DNA/química , Interações Hidrofóbicas e Hidrofílicas , Micelas , MicroRNAs/análise , Polímeros/química , Alcanos/química , Fatores de Tempo
18.
Anal Chim Acta ; 1126: 24-30, 2020 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-32736721

RESUMO

Herein, an orbitron-like three-dimensional (3D) DNA clip-based nanomachine was proposed for ultrasensitive fluorescent bioassay of microRNA, which was constructed by mechanically interlocking double-DNA-ring with two single-stranded DNAs, performing an orbitron-like 3D structure with double freely rotated DNA rings as the open state. In the presence of target microRNA, the proposed orbitron-like 3D DNA clip can alter its structure from open to closed state in identification of the target microRNA, generating the closure between the previously modified fluorescent dyes and the quenchers to perform a "signal off" fluorescent signal correlated with the concentration of target microRNA. Compared with the normal DNA nanomachines, such as DNA tweezers constructed by self-assembly of three single-stranded DNAs which regulated the open and closed states on the basis of linear conformational changes, the proposed 3D DNA clip-based nanomachine with high mechanical rigidity realized the conformational changes in 3D space with the assistance of target microRNA, which could effectively increase the adjustable distance range and reduce the background signal. Furthermore, the 3D DNA clip-based nanomachine was applied in the fluorescent detection of microRNA-21 with favorable performances for the sensitive detection of microRNA in cells, providing a new avenue for early clinical diagnoses of disease.


Assuntos
Técnicas Biossensoriais , MicroRNAs , Bioensaio , DNA/genética , MicroRNAs/genética , Instrumentos Cirúrgicos
19.
Anal Chem ; 92(16): 11044-11052, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32677426

RESUMO

Herein, an amphiphilic perylene derivative (denoted as PTC-DEDA) was explored as DNA intercalators endowed with an enhanced affinity and intense electrochemiluminescence (ECL) to construct a target-induced DNA hydrogel biosensing platform for the sensitive detection of microRNA let-7a (miRNA let-7a). Specifically, the DNA hydrogel with numerous dendritic DNA structures was in situ generated via a target-induced nonlinear hybrid chain reaction in the presence of miRNA let-7a, which possessed a large loading capacity to entrap massive DNA intercalators. Then, the PTC-DEDA with positive charges could easily intercalate into the DNA grooves due to the inherent amphipathic structure, achieving a strong ECL signal. Using the proposed PTC-DEDA as both DNA intercalators and ECL emitters, the DNA hydrogel biosensing platform exhibited a high stability and an excellent sensitivity for miRNA let-7a, with a desirable linear range (10 fM to 10 nM) and a low detection limit (1.49 fM). Significantly, the work provides a potential alternative to develop simple and high-efficiency ECL platforms for biochemical analysis applications.


Assuntos
Técnicas Biossensoriais/métodos , DNA/química , Hidrogéis/química , Substâncias Intercalantes/química , MicroRNAs/análise , Linhagem Celular Tumoral , Ouro/química , Humanos , Limite de Detecção , Substâncias Luminescentes/química , Nanopartículas de Magnetita/química , Paládio/química , Perileno/análogos & derivados , Sulfatos/química
20.
Chem Commun (Camb) ; 56(63): 9000-9003, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32638738

RESUMO

A kind of organic microcrystal, 9,10-diphenylanthracene microcrystals (DPA MCs), was developed as a novel electrochemiluminescence (ECL) coreactant accelerator to efficiently catalyze dissolved O2 for more reactive oxygen species (ROSs) generation, achieving intense ECL for a H2O2-free luminol system. Moreover, based on this ternary ECL system, a signal "off-on" ECL biosensor for microRNA-21 (miRNA-21) detection was constructed combining a sensitive target recycling amplification strategy and an enzyme-mediated recycling strand displacement reaction (RSDR).


Assuntos
Técnicas Biossensoriais/métodos , Luminol/química , MicroRNAs/análise , Antracenos/química , Catálise , Linhagem Celular Tumoral , Humanos , Medições Luminescentes , Técnicas de Amplificação de Ácido Nucleico , Espécies Reativas de Oxigênio/química , Espécies Reativas de Oxigênio/metabolismo
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