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1.
Talanta ; 222: 121517, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33167227

RESUMO

A direct-readout photoelectrochemical (PEC) lab-on-paper device based on coupled an electricity generating system and paper supercapacitors was established for highly sensitive detection of adenosine triphosphate (ATP). Concretely, CdSe quantum dots (QDs) decorated ZnO networks assembled sensing surface provided outstanding photoelectric properties, on which glucose oxidase (GOx) labeled aptamer was subsequently immobilized via the hybridization chain reaction. With analytes present, specific recognition was stimulated by aptamer, resulting in labeled GOx released. Such released GOx could flow to electrochemical cell to conduct electrochemical redox reactions, which could effectively produce electricity that was stored by capacitor I. Sequentially, photoactive material produced an outstanding voltage due to the decrease of steric hindrance on the sensing interface, which was utilized for charging an external capacitor II. The two instantaneous current was acquired along with the discharge of capacitor I and II by digital multimeter (DMM) readout, respectively. The summational current values performed an increment in pace with the addition of target ATP concentration with the dynamic working range from 10 nM to 3 µM and a detection limit of 6.3 nM attained. Significantly, the signal amplified strategy utilizing as-generated electricity from electrochemical redox reactions were isolated from the photoelectrodes, which was beneficial for amplifying the signal response in the PEC matrices and the development of more efficient signal performance.

2.
J Microbiol ; 58(9): 812-820, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32870487

RESUMO

Enterovirus D68 (EVD68) is an emerging pathogen that recently caused a large worldwide outbreak of severe respiratory disease in children. However, the relationship between EVD68 and host cells remains unclear. Caspases are involved in cell death, immune response, and even viral production. We found that caspase-3 was activated during EVD68 replication to induce apoptosis. Caspase-3 inhibitor (Z-DEVD-FMK) inhibited viral production, protected host cells from the cytopathic effects of EVD68 infection, and prevented EVD68 from regulating the host cell cycle at G0/G1. Meanwhile, caspase-3 activator (PAC-1) increased EVD68 production. EVD68 infection therefore activates caspase-3 for virus production. This knowledge provides a potential direction for the prevention and treatment of disease related to EVD68.

3.
J Hazard Mater ; 403: 123601, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32768863

RESUMO

As a nondegradable environmental pollutant, lead ion (Pb2+) has been proven to be deleterious for environmental and health. Conveniently, quickly and accurately on-site detection of Pb2+ is of paramount importance. Herein, an electrochemiluminescence (ECL) assay protocol using two-dimensional black phosphorus (2D BP) nanoflakes as new ECL emitter for highly sensitive and selective trace Pb2+ was designed on the basis of Pb2+ induced ECL resonance energy transfer (ECL-RET) between 2D BP nanoflakes and Ag/AgCl nanocubes. Anodic green ECL emission of BP nanoflakes without any coreactants was achieved. It is noteworthy that the possible ECL mechanism and the influence of coreactants on the ECL behaviour of BP nanoflakes were further investigated. Benefitting from the well match between the ECL emission spectrum of BP nanoflakes (∼510 nm) and the absorption spectrum of Ag/AgCl nanocubes (200-300 nm and 400-700 nm), effective energy transfer yielded. The introduction of Pb2+ would lead to the detachment of Ag/AgCl nanocubes then result in an enhanced ECL emission. Based on this, the proposed method could accurately quantify the Pb2+ in the range from 0.5 pM to 5 nM, which exhibited comparative performance to previous work. Furthermore, this study presents the example of employing 2D BP nanoflakes as ECL emitters and constructing a coreactant-free ECL sensing platform, which might open up a promising route for the potential design and implement in clinical analysis.

4.
Mikrochim Acta ; 187(9): 530, 2020 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-32860548

RESUMO

A paper-based electrochemiluminescence (ECL) biosensor characterized by the signal amplification of reticular DNA-functionalized PtCu nanoframes (DNA-PtCuTNFs) and analyte-triggered DNA walker was developed for sensitive streptavidin assay. Silver microflower functionalized paper-based sensing platform was prepared to fix the hairpin strand (S1). With addition of the streptavidin, plenty of DNA walkers consisting of the walking strands (S2) labeled with biotin and streptavidin were established, which protected S2 from digestion via the terminal protection mechanism. The sequential introduction of the DNA walker and capture probe initiated the hairpin structure opening of S1 and strand displacement reaction (SDR) happening, causing the S2 release. Subsequently, S1 hybridized with S3. The free S2 further hybridized with adjacent S1 to trigger the next cycle. After multiple cycles, the DNA-PtCuTNFs, the fire-new signal enhancer, with remarkable peroxidase activity, were successfully attached onto the paper electrode via metal-catalyst-free click chemistry. Based on the SDR of the DNA walker and the catalysis of DNA-PtCuTNFs, a significantly boosted ECL signal of luminol was obtained. Under the optimal conditions, the developed sensor for streptavidin assay exhibited a low detection limit of 33.4 fM with a linear range from 0.1 pM to 0.1 µM. Graphical abstract.

5.
ACS Appl Mater Interfaces ; 12(38): 42604-42611, 2020 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-32852185

RESUMO

A novel photoelectrochemical (PEC) aptasensor was fabricated for DNA detection based on the coupling of cosensitization and peroxidase-like catalytic activity. Specifically, the surfaces of branched-TiO2 nanorods (B-TiO2 NRs) were modified with Cd2+ and S2+ to obtain B-TiO2 NRs/CdS hybrid structures, which were subsequently used as matrices to immobilize hairpin DNA (hDNA) probes. CdTe/TCPP (TCPP = meso-tetra(4-carboxyphenyl)-porphine) used for signal amplification was labeled on the terminal of the hDNA probe. Without the target DNA (tDNA) presence, the immobilized hDNA probe with CdTe/TCPP possessed a hairpin form and was located near the B-TiO2 NRs/CdS electrode surface, forming a cosensitized structure formation and then generating strong photocurrent with H2O2 as the electron donor. During detection, the specific recognition of tDNA by the sensing hDNA probe triggered the formation of the G-quadruplex/hemin DNAzyme, which effectively catalyzed the decomposition of H2O2. Meanwhile, cosensitization disappeared when the hDNA probe hybridized with tDNA, further reducing the photocurrent. With a double-signal amplification strategy, the sensing platform designed in this work demonstrated a linear detection ability in the 0.5 fM-5 nM range with a detection limit equal to 0.14 fM. Notably, through encoding in the base sequences of the hDNA and marking it, a versatile PEC platform could be structured for the detection of various DNA targets, which could promise applications in point-of-care diagnostic fields.

6.
Proc Natl Acad Sci U S A ; 117(31): 18504-18510, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32699145

RESUMO

The human blood protein vitronectin (Vn) is a major component of the abnormal deposits associated with age-related macular degeneration, Alzheimer's disease, and many other age-related disorders. Its accumulation with lipids and hydroxyapatite (HAP) has been demonstrated, but the precise mechanism for deposit formation remains unknown. Using a combination of solution and solid-state NMR experiments, cosedimentation assays, differential scanning fluorimetry (DSF), and binding energy calculations, we demonstrate that Vn is capable of binding both soluble ionic calcium and crystalline HAP, with high affinity and chemical specificity. Calcium ions bind preferentially at an external site, at the top of the hemopexin-like (HX) domain, with a group of four Asp carboxylate groups. The same external site is also implicated in HAP binding. Moreover, Vn acquires thermal stability upon association with either calcium ions or crystalline HAP. The data point to a mechanism whereby Vn plays an active role in orchestrating calcified deposit formation. They provide a platform for understanding the pathogenesis of macular degeneration and other related degenerative disorders, and the normal functions of Vn, especially those related to bone resorption.


Assuntos
Cálcio/metabolismo , Durapatita/metabolismo , Degeneração Macular/metabolismo , Vitronectina/metabolismo , Sítios de Ligação , Cálcio/química , Durapatita/química , Humanos , Ligação Proteica , Vitronectina/química
7.
Anal Chem ; 92(11): 7604-7611, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32364705

RESUMO

Herein an ultrasensitive photoelectrochemical (PEC)/visual biosensor coupled with a multiple signal amplification strategy was proposed for the detection of nucleic acids. The initial signal amplification was achieved via ternary AgInSe2 quantum dot (QD)-sensitized ZnO nanoflowers (ZnO NFs) to form an excellent photoelectric layer. A gold-modified nanorod-anchored CeO2 (Au@NR-CeO2) octahedron was introduced as a multifunctional signal regulator via the formation of triple helix molecules. The Au@NR-CeO2 octahedron could not only quench the photocurrent signal due to the competitive capture of photon energy and electron donors with the photoelectric layer but could also act like a peroxidase to catalyze the formation of mimetic enzymatic catalytic precipitation (MECP) on the surface of the photoelectric layer. Furthermore, the steric hindrance effect from the Au@NR-CeO2 octahedron further reduced the output of the photocurrent signal. After incubation with t-DNA, the triple helix conformation was disassembled and the Au@NR-CeO2 octahedron was released from the electrode surface, leading to the significant increase of photocurrent signal. Meanwhile, the released Au@NR-CeO2 octahedron could flow into the colorimetric area of the lab-on-paper device to catalyze the occurrence of the color reaction, achieving a visual detection for t-DNA. On the basis of the multiple signal amplification strategy, t-DNA was detected specifically with a lower limit of detection of 0.28 fM and a wider linear range from 0.5 fM to 50 nM. The proposed method has the potential utility to detect a variety of nucleic acids and biomarkers.

8.
Anal Chem ; 92(10): 6822-6826, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32378879

RESUMO

Exploring efficient luminophores in the electrochemiluminescence (ECL) system is highly desired to pursue a sensitive ECL sensing platform. Herein, the black phosphorus nanosheets (BP NSs) with excellent ECL properties are investigated and serve as the luminophore with the coreactant of peroxydisulfate (S2O82-) solution. Moreover, owing to the overlapping of emission and absorbance spectra, effective resonance energy transfer (RET) is realized between the BP NSs and the introduced Au nanoparticles. In order to achieve the portable and miniaturized developing trends for the paper-based ECL sensing platform, a paper-based perovskite solar cell (PSC) device is designed to act as the power source to replace the commonly utilized expensive and cumbersome electrochemical workstation. Benefiting from that, a PSC driven paper-based constant potential ECL-RET sensing platform is constructed, thereby realizing sensitive microRNAs (miRNAs) detection. What's more, to attain the preferable analytical performance, the duplex-specific nuclease (DSN) is also introduced to assist the target recycling signal amplification strategy. Based on this, highly sensitive detection of miRNA-107 with a range from 0.1 pM to 15 nM is achieved by this designed sensing platform. Most importantly, this work not only pioneers a precedent for developing a high-sensitivity PSC triggered ECL sensing platform but also explores the application prospect of BP nanomaterial in the field of bioanalysis.

9.
ACS Sens ; 5(5): 1482-1490, 2020 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-32362115

RESUMO

Developing efficient strategies for sensitive detection of microRNAs, the noncoding bioactive molecules and well-established biomarkers, has aroused great interests due to its great potential values in genetic and pathological analyses. Herein, a highly selective and disposable paper-based photoelectrochemical (PEC) sensor was rationally designed for sensing microRNA based on simple self-assembly of a target-triggerable DNA motor and nanozyme-catalyzed multistage biocatalytic precipitation reaction. Specifically, a brand-new type II heterojunction of TiO2-CeO2 nanotubes decorated with carbon fiber paper (CFP) was first prepared, which gave an enhanced photoreactive surface and realized fast electron transport and extraction, markedly accelerating photoelectric conversion efficiency of the sensor. For achieving target detection, cascade nanozyme centers of the CeO2 and Au nanoparticles modified by cyclodextrin were drafted, greatly decreasing the photocurrent intensity and achieving an ultralow background signal. With target introduction, the DNA motor was activated and automatically moved along the predesigned route driven by an endonuclease cleavage reaction, resulting in more substrate probe digestion and nanozyme release from CFP. Consequently, the repressive inner enhancement mechanism was gradually renewed with constant advancement of the enzymatic reaction and walker probe walking progressively, eventually allowing multiple enzymatic factor output in each target import. As a proof-of-concept application, the developed PEC sensor successfully performed detection of miRNA-141, showing a low detection limit of 0.6 fM, and was further applied to real sample bioassays with satisfying results. This work proposes promising strategies to boost the catalytic cascade DNA-motor adhibition in biological samples analysis and also exhibits potential capability in detection of other targets.

10.
Mikrochim Acta ; 187(3): 193, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32124067

RESUMO

An ultrasensitive fluorescence sensing strategy for kanamycin (KANA) determination using endonuclease IV (Endo IV)-powered DNA walker, and hybridization chain reaction (HCR) amplification was reported. The sensing system consists of Endo IV-powered 3D DNA walker using for the specific recognition of KANA and the formation of the initiators, two metastable hairpin probes as the substrates of HCR and a tetrahydrofuran abasic site (AP site)-embeded fluorescence-quenched probe for fluorescence signal output. On account of this skilled design of sensing system, the specific binding between KANA and its aptamer activates DNA walker, in which the swing arm can move autonomously along the 3D track via Endo IV-mediated hydrolysis of the anchorages, inducing the formation of initiators that initiates HCR and the following Endo IV-assisted cyclic cleavage of fluorescence reporter probes. The use of Endo IV offers the advantages of simplified and accessible design without the need of specific sequence in DNA substrates. Under the optimal experimental conditions, the fluorescence biosensor shows excellent sensitivity toward KANA detection with a detection limit as low as 1.01 pM (the excitation wavelength is 486 nm). The practical applicability of this strategy is demonstrated by detecting KANA in spiked milk samples with recovery in the range of 98 to 102%. Therefore, this reported strategy might create an accurate and robust fluorescence sensing platform for trace amounts of antibiotic residues determination and related safety analysis. Graphical abstract Highly efficient fluorescence sensing of kanamycin using Endo IV-powered DNA Walker and hybridization chain, reaction amplification, Xiaonan Qu, Jingfeng Wang, Rufeng Zhang, Yihan Zhao, Shasha Li, Yu Wang, Su Liu*, Jiadong Huang, and Jinghua Yu, an ultrasensitive fluorescence sensing strategy for kanamycin determination using endonuclease IV-powered DNA walker, and hybridization chain reaction amplification is reported.


Assuntos
Antibacterianos/análise , Técnicas Biossensoriais/métodos , DNA/química , Desoxirribonuclease IV (Fago T4-Induzido)/química , Desoxirribonuclease I/química , Corantes Fluorescentes/química , Canamicina/análise , Animais , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/instrumentação , Contaminação de Alimentos/análise , Ouro/química , Limite de Detecção , Nanopartículas Metálicas/química , Técnicas de Amplificação de Ácido Nucleico/métodos , Hibridização de Ácido Nucleico/métodos
11.
Analyst ; 145(8): 2975-2981, 2020 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-32118243

RESUMO

DNA walkers, one of the artificial molecular machines which are constructed via smart synthetic DNA, have attracted rapidly growing attention from researchers in the biosensing field. In this work, we design an Exonuclease III (Exo III)-aided target-aptamer binding recycling (ETBR) activated bipedal DNA machine for highly sensitive electrochemical detection of antibiotics. To the best of our knowledge, this is the first time that a bipedal DNA machine has been applied in electrochemical sensing for antibiotics. On the one hand, the bipedal DNA walker exceeds the conventional single swing arm DNA walker in terms of walking efficiency and stability. On the other hand, the ETBR strategy, along with efficient strand displacement amplification via stepwise movement of a bipedal DNA walker significantly promotes the signal amplification efficiency. Under optimal conditions, this bipedal DNA machine possesses a detection limit of 7.1 fM within a linear detection range from 10 fM to 100 pM. Moreover, this electrochemical biosensor is expected to detect a wide variety of analytes using the corresponding target recognition probes. Thus, our proposed strategy offers a highly efficient, stable and practical platform for small molecule analysis.

12.
ACS Appl Mater Interfaces ; 12(15): 17177-17184, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32193932

RESUMO

In this work, a lab-on-paper cathode photoelectrochemical (PEC) sensing platform was constructed for ultrasensitive microRNA-141 (miRNA-141) assay using cascaded multiple photo-active structures as signal generators and hemin/Pt nanoparticle (Pt NP) trunk-branching-decorated DNA dendrimers as signal reinforcers. Specifically, pyramid-like Cu2O was first in situ grown on the Au nanoparticle-functionalized tangled cellulose fibers network, followed by the sensitization of trepang-like BiVO4-Bi2S3 heterostructures, forming the cascaded sensitization structures. Then, the DNA dendrimer was introduced into the photocathode sensing interface by coupling the duplex-specific-nuclease (DSN)-induced target recycling reaction with multiple-branched hybridization chain reaction (MHCR). The programmed target recycling procedures propelled using DSN guaranteed the highly amplified transduction of miRNA-141 to the exposed initiator strand, which triggered the cascaded MHCR accompanied by the formation of the DNA dendrimer with unique trunk-branching structures. Finally, the hemin/Pt NP trunk-branching-decorated DNA dendrimer (HPTD) was acquired by the assembly of Pt NPs and hemin on the trunk and branch, respectively. The resulting HPTD with the synergy catalysis of Pt NPs and hemin could efficiently catalyze the decomposition of H2O2 for in situ generation of O2 as the electron acceptor, leading to an enhanced photocurrent response. Based on the target-dependent photocurrent enhancement, ultrasensitive determination of miRNA-141 was realized with persuasive selectivity, high stability, and excellent reproducibility. Thus, the proposed paper-based cathode PEC sensing platform possessed promising application prospect in clinical miRNA diagnosis.

13.
Anal Chim Acta ; 1104: 156-163, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32106947

RESUMO

A novel fluorescence sensing strategy for ultrasensitive and highly specific detection of adenosine triphosphate (ATP) has been developed by the combination of the proximity ligation assay with bidirectional enzymatic repairing amplification (BERA). The strategy relies on proximity binding-triggered the release of palindromic tail that initiates bidirectional cyclic enzymatic repairing amplification reaction with the aid of polymerase and two DNA repairing enzymes, uracil-DNA glycosylase (UDG) and endonuclease IV (Endo IV). A fluorescence-quenched hairpin probe with a palindromic tail at the 3' end is skillfully designed that functions as not only the recognition element, primer, and polymerization template for BERA but also the indicator for fluorescence signal output. On the basis of the amplification strategy, this biosensor displays excellent sensitivity and selectivity for ATP detection with an outstanding detection limit of 0.81 pM. Through simultaneously enhancing the target response signal value and reducing nonspecific background, this work deducted the background effect, and showed high sensitivity and reproducibility. Moreover, our biosensor also shows promising potential in real sample analysis. Therefore, the proximity-enabled BERA strategy indeed creates a simple and valuable fluorescence sensing platform for ATP identification and related disease diagnosis and biomedical research.


Assuntos
Trifosfato de Adenosina/análise , Técnicas Biossensoriais/métodos , Desoxirribonuclease IV (Fago T4-Induzido)/química , Técnicas de Amplificação de Ácido Nucleico , Uracila-DNA Glicosidase/química , Trifosfato de Adenosina/sangue , Técnicas Biossensoriais/instrumentação , Cromatografia Líquida de Alta Pressão , Desoxirribonuclease IV (Fago T4-Induzido)/genética , Eletroforese em Gel de Poliacrilamida , Corantes Fluorescentes/química , Células HeLa , Humanos , Limite de Detecção , Espectrometria de Fluorescência , Uracila-DNA Glicosidase/genética
14.
Anal Chem ; 92(4): 2902-2906, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-32013407

RESUMO

Efficient separation of electron-hole pairs is vitally crucial to enhancing the analytical performance of paper-based photoelectrochemical (PEC) bioanalysis. Herein, a simple but effective strategy is developed to modulate the effective separation of photogenerated electrons and holes via introducing a polar charge carriers-created (PCC) electric field induced by a classical perovskite ferroelectric BaTiO3 (BTO). By inserting it between the n-type WO3 nanoflakes and p-type Cu2O (WO3 nanoflakes/BTO/Cu2O), the photoelectrode is endowed with a renewable PCC electric field, as a sustaining driving force, to guarantee the realization of directional separation of charge carrier (DSCC) strategy in PEC bioanalysis. The enduring PCC electric field can attract the electrons of Cu2O and holes of WO3, respectively, thereby regulating the directional migration of charge carriers and achieving an enhanced PEC photocurrent for the ultrasensitive quantification based on the highly efficient separation of electron-hole pairs. Consequently, with respect to WO3 nanoflakes/Cu2O and WO3 nanoflakes photoelectrode, the polarized WO3 nanoflakes/BTO/Cu2O photoelectrode exhibits 1.7 and 10.9 times higher photocurrent density, respectively. Benefiting from this, the prominent photocurrent density is obtained which is extremely beneficial for enhancing the sensitivity of PEC bioanalysis. Ultimately, the ultrasensitive detection of model prostate specific antigen (PSA) is realized and presents a linear range of 0.1 pg/mL-50 ng/mL with the detection limitation of 0.036 pg/mL. This work provides the basis for understanding the role of the polarized electric field induced by ferroelectric in tuning the charge separation as well as insights on strategies for constructing high-performance paper-based PEC bioanalysis.

15.
Biosens Bioelectron ; 150: 111958, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31929089

RESUMO

In this work, a peptide-based photoelectrochemical (PEC) biosensor was constructed based on CdTe/TiO2 sensitized structure as electrode and CuS nanocrystals as signal amplifier for the ultrasensitive detection of protein. After peptide was fixed to the CdTe/TiO2 electrode surface, the double-helix DNA (dsDNA) was immobilized at the end of the peptide and used as a carrier to immobilize the doxorubicin-copper sulfide nanocrystals (Dox-CuS) conjugates. As a proof of concept, prostate specific antigen (PSA) has been chosen as the model. In absence of PSA, CuS nanocrystals could consume electron donors and exciting light energy. Additionally, the steric hindrance effect of biomacromolecules hindered the movement of electron donors to the photoelectrode. Eventually, the photoelectric response signal was reduced, and the biosensor was in a "signal off" state. When PSA existed, the PSA specifically cleaved the peptide, and DNA/Dox-CuS probes were released from the electrode surface, resulting in a "signal on" state. The PEC biosensor revealed good specificity, stability, and reproducibility, and it exhibited excellent application in PSA analysis with a linear range from 0.005 to 20 ng mL-1 and a low detection limit of 0.0015 ng mL-1. This PEC biosensor may have potential applications in bioanalysis, disease diagnostics, and clinical biomedicine.


Assuntos
Técnicas Biossensoriais/métodos , Cobre/química , Nanopartículas/química , Peptídeos/química , Antígeno Prostático Específico/análise , Compostos de Cádmio/química , Técnicas Eletroquímicas/métodos , Humanos , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Nanotubos/química , Telúrio/química , Titânio/química
16.
ACS Appl Mater Interfaces ; 12(7): 8845-8854, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31989810

RESUMO

Real-time monitoring of neonicotinoid pesticide residues is of great significance for food security and sustainable development of the ecological environment. Herein, a paper-based surface-enhanced Raman scattering (SERS) amplified approach was proposed by virtue of multilayered plasmonic coupling amplification. The unique plasmonic SERS multilayer was constructed using three-dimensional (3D) silver dendrite (SD)/electropolymerized molecular identifier (EMI)/silver nanoparticle (AgNP) sandwich hybrids with multiple hotspots and a strong electromagnetic field in nanogaps. Dendritelike 3D silver materials with remarkably high accessible surface areas and the lightning rod effect constituted the first-order enhancement of paper-based sensors. Molecular identifiers coated upon an SD layer as the interlayer were used for target capture and enrichment. Subsequently, AgNPs featuring rough surface and local plasma resonance decorated as the top layer formed the secondary enhancement of the amplification strategy. As the most brilliant part, dendritelike 3D silver coupled with AgNPs has established double Ag layers to accomplish a multistage enhancement of SERS signals based on the superposition of their electromagnetic fields. Owning to the distinctive design of the multiple coupling amplification strategy, the fabricated SERS paper chips demonstrated impressive specificity and ultrahigh sensitivity in the detection of imidacloprid (IMI), with a detection limit as low as 0.02811 ng mL-1. More importantly, the multiple SERS enhancement paper chip holds great potential for automated screening of a variety of contaminants.

17.
Anal Chem ; 92(5): 3874-3881, 2020 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-31995985

RESUMO

Currently, portable, low-cost, and easy to operate on-chip analytical units are urgently demanded to meet the requirement for point-of-care testing in resource-limited regions. Herein, a dual-mode lab-on-paper platform is presented, which integrates distance-based visualized readout with ratiometric electrochemiluminescence (ECL) assay in one device. The distance-based measurement is based on a brown visualized strip generated from the oxidation reaction of 3,3'-diaminobenzidine in the presence of H2O2 initiated by horseradish peroxidase (HRP). Notably, visualized semiquantitative results are displayed as the length of a brown bar chart directly on the device-without the need for any data processing or plotting steps, thus avoiding the error caused by the naked eye for distinguishing the color depth. On the contrary, a ratiometric ECL technique was employed for accurate analysis based on the specific biorecognition between Pb2+-dependent DNAzymes and targets. Concretely, upon addition of Pb2+ into the fabricated device, cleaved oligonucleotide fragments connected with HRP functionalized Au nanocubes could permeate through the cellulose on account of their size that is smaller than paper pores, quench the ECL signal of the CdS quantum dots because of resonance energy transfer, and synchronously boost the ECL intensity generated from luminol by catalyzing H2O2. As a consequence, satisfied prediction and accurate monitoring performance was obtained in the range 0.1-2000 nM and 0.01-2000 nM by measuring the length of colored product and the ratio of ECL intensity, respectively. The beneficial advantages of low cost, high efficiency, and the capacity to perform dual-mode assay qualify this innovative device for use with diverse applications.

18.
EMBO Rep ; 21(1): e47528, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31797533

RESUMO

SAMHD1 possesses multiple functions, but whether cellular factors regulate SAMHD1 expression or its function remains not well characterized. Here, by investigating why cultured RD and HEK293T cells show different sensitivity to enterovirus 71 (EV71) infection, we demonstrate that SAMHD1 is a restriction factor for EV71. Importantly, we identify TRIM21, an E3 ubiquitin ligase, as a key regulator of SAMHD1, which specifically interacts and degrades SAMHD1 through the proteasomal pathway. However, TRIM21 has no effect on EV71 replication itself. Moreover, we prove that interferon production stimulated by EV71 infection induces increased TRIM21 and SAMHD1 expression, whereas increasing TRIM21 overrides SAMHD1 inhibition of EV71 in cells and in a neonatal mouse model. TRIM21-mediated degradation of SAMHD1 also affects SAMHD1-dependent restriction of HIV-1 and the regulation of interferon production. We further identify the functional domains in TRIM21 required for SAMHD1 binding and the ubiquitination site K622 in SAMHD1 and show that phosphorylation of SAMHD1 at T592 also blocks EV71 restriction. Our findings illuminate how EV71 overcomes SAMHD1 inhibition via the upregulation of TRIM21.

19.
Biosens Bioelectron ; 150: 111917, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31784310

RESUMO

This paper introduces a paper-based closed Au-bipolar electrode (BPE) biosensing system for the rapid and sensitive electrochemiluminescence (ECL) detection of miRNA-155. This microfluidic paper-based sensing platform is formed by wax-printing technology, screen printing method and in-situ Au nanoparticles (NPs) growth to form hydrophilic cells, hydrophobic boundaries, water proof electronic bridge, driving electrode regions and bipolar electrode regions. For rapid and sensitive detection, the cathode of bipolar electrode was modified with the prepared DNA (S1)-AuPd NPs by hybridization chain reaction, in which the target could initiate multiple cycles reaction to load more AuPd NPs which catalyzed H2O2 reduction. In addition, a classical ECL system tris (2,2'-bipyridine) ruthenium (II)- tripropylamine (Ru(bpy)32+/TPrA) exists at the anode of the bipolar electrode. Due to the charge balance between the anode and the cathode of BPE, the ECL signal response of Ru(bpy)32+/TPrA system was enhanced in the reporting cell. The intensity of ECL was quantitatively correlated with the concentration of miRNA-155 in the range of 1 pM-10 µM with the detection limit 0.67 pM. Moreover, this method paves a novel way for highly sensitive detection of miRNA-155 in clinical application.

20.
Eur J Clin Microbiol Infect Dis ; 39(2): 219-227, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31650411

RESUMO

Previous studies have shown increased risk of herpes zoster (HZ) infection in patients with inflammatory bowel disease (IBD). The aim of this study is to better characterize this possible association by conducting a meta-analysis. A comprehensive search of relevant literature until April 30, 2019, was performed. Data on HZ infection and medications in patients with IBD and controls were extracted. The relative risk (RR) and 95% confidence interval (CI) were calculated. Subgroup analyses were performed to assess the source of heterogeneity. Seven cohort studies were included that involved more than 1,000,000 participants. The RR of HZ infection in patients with Crohn's disease (CD) compared with non-CD patients was 1.74 (95% CI 1.57-1.92, p < 0.001). The pooled RR of HZ infection in patients with ulcerative colitis (UC) compared with non-UC was 1.40 (95% CI 1.31-1.50, p < 0.001). Subgroup analyses revealed that age, race, and publication year contribute to heterogeneity. We also found that steroid users were at increased risk of HZ in CD (OR = 1.78, 95% CI 1.10-2.88). Steroid users and anti-TNFα users were at increased risk of HZ in UC, with RRs of 1.99 (95% CI 1.64-2.42) and 2.29 (95% CI 1.52-3.45), respectively. Begg's test and Egger's test suggested no publication bias. There was a 74% increased risk of HZ infection in patients with CD and 40% increased risk of HZ infection in patients with UC compared with that in non-IBD. IBD patients with high risk of HZ infection may benefit from an HZ vaccine.

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