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1.
ACS Appl Mater Interfaces ; 13(42): 49754-49761, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34657424

RESUMO

A reliable and sensitive detection approach for SARS-CoV 2 is essential for timely infection diagnosis and transmission prevention. Here, a two-dimensional (2D) metal-organic framework (MOF)-based photoelectrochemical (PEC) aptasensor with high sensitivity and stability for SARS-CoV 2 spike glycoprotein (S protein) detection was developed. The PEC aptasensor was constructed by a plasmon-enhanced photoactive material (namely, Au NPs/Yb-TCPP) with a specific DNA aptamer against S protein. The Au NPs/Yb-TCPP fabricated by in situ growth of Au NPs on the surface of 2D Yb-TCPP nanosheets showed a high electron-hole (e-h) separation efficiency due to the enhancement effect of plasmon, resulting in excellent photoelectric performance. The modified DNA aptamer on the surface of Au NPs/Yb-TCPP can bind with S protein with high selectivity, thus decreasing the photocurrent of the system due to the high steric hindrance and low conductivity of the S protein. The established PEC aptasensor demonstrated a highly sensitive detection for S protein with a linear response range of 0.5-8 µg/mL with a detection limit of 72 ng/mL. This work presented a promising way for the detection of SARS-CoV 2, which may conduce to the impetus of clinic diagnostics.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Estruturas Metalorgânicas/química , SARS-CoV-2/química , Glicoproteína da Espícula de Coronavírus/análise , Sequência de Bases , Técnicas Biossensoriais/instrumentação , COVID-19/diagnóstico , DNA/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Ouro/química , Ouro/efeitos da radiação , Humanos , Ácidos Nucleicos Imobilizados/química , Luz , Limite de Detecção , Nanopartículas Metálicas/química , Nanopartículas Metálicas/efeitos da radiação , Faringe/virologia , Processos Fotoquímicos , Porfirinas/química , Glicoproteína da Espícula de Coronavírus/química , Itérbio/química
2.
ACS Appl Mater Interfaces ; 13(30): 35533-35544, 2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34286570

RESUMO

Accelerated DNA hybridization chain reactions (HCRs) using DNA origami as a scaffold have received considerable attention in dynamic DNA nanotechnology. However, tailor-made designs are essential for DNA origami scaffolds, hampering the practical application of accelerated HCRs. Here, we constructed the semilocalized HCR and localized HCR systems using magnetic beads (MBs) as a simple scaffold to explore them for the enzyme-free miR-21 detection. The semilocalized HCR system relied on free diffusing one hairpin DNA and MBs immobilized with another hairpin DNA, and the localized HCR system relied on MBs coimmobilized with two hairpin DNAs. We demonstrated that the DNA density on MBs plays a critical role in HCR kinetics and limit of detection (LOD). Among semilocalized HCR systems, MBs with a medium DNA density showed a faster HCR and lower LOD (10 pM) than the diffusive (conventional) HCR system (LOD: 86 pM). In contrast, the HCR further accelerated for the localized HCR systems as the DNA density increased. The localized HCR system with the highest DNA density showed the fastest HCR and the lowest LOD (533 fM). These findings are of great importance for the rational design of accelerated HCRs using simple scaffolds for practical applications.


Assuntos
DNA/química , MicroRNAs/sangue , Nanoestruturas/química , Técnicas de Amplificação de Ácido Nucleico/métodos , Animais , Bovinos , DNA/genética , Humanos , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/genética , Sequências Repetidas Invertidas , Limite de Detecção , Fenômenos Magnéticos , MicroRNAs/genética , Hibridização de Ácido Nucleico
3.
Carbohydr Polym ; 269: 118333, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34294343

RESUMO

Metal-free cost-efficient biocompatible molecules are beneficial for opto-electrochemical bioassays. Herein, chitosan (CS) conjugated butein is prepared via graft polymerization. Structural integrity between radical active sites of CS and its probable conjugation routes with reactive OH group of butein during grafting were comprehensively studied using optical absorbance/emission property, NMR, FT-IR and XPS analysis. Fluorescence emission of CS-conjugated butein (CSB) was studied in dried flaky state as well as in drop casted form. Cyclic voltammetric study of CSB modified glassy carbon electrode exhibits 2e-/2H+ transfer reaction in phosphate buffered saline electrolyte following a surface-confined process with a correlation coefficient of 0.99. Unlike pristine butein, CSB modified electrode display a highly reversible redox behavior under various pH ranging from 4 to 9. For the proof-of-concept CSB-modified flexible screen printed electrodes were processed for electrochemical biosensing of exosomal CD24 specific nucleic acid at an ultralow sample concentration, promising for ovarian cancer diagnosis.


Assuntos
Antígeno CD24/genética , Chalconas/química , Quitosana/análogos & derivados , DNA/análise , Exossomos/química , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Chalconas/síntese química , Quitosana/síntese química , Sondas de DNA/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Estudo de Prova de Conceito
5.
Chem Commun (Camb) ; 57(65): 8039-8042, 2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34291259

RESUMO

Two-dimensional (2D) hexagonal boron nitride nanosheet (h-BNNS) is proposed as an effective nanoquencher for fluorescence detection of biocompatible microRNA. Compared with bulk hexagonal boron nitride (h-BN), the exfoliated ultrathin nanosheet has a narrow band gap and increased conductivity, thus enabling fast electron transfer with this electron acceptor for more effective fluorescence detection of microRNA. Remarkably, using the nanoprobe consisting of h-BNNS and FAM dye-labeled ssDNA, a low detection limit of 2.39 nM is achieved and a rapid fluorescence response is observed compared with previously reported fluorescence sensing materials. More importantly, this sensing system could also distinguish base-mismatched microRNA, suggesting that the proposed sensing platform held excellent selectivity and great promise for application in the detection of nucleotide polymorphism. This work will benefit microRNA-related fundamental research and disease diagnosis.


Assuntos
Compostos de Boro/química , Corantes Fluorescentes/química , MicroRNAs/análise , Nanoestruturas/química , Pareamento Incorreto de Bases , Biomarcadores Tumorais/análise , Biomarcadores Tumorais/genética , DNA de Cadeia Simples/química , DNA de Cadeia Simples/genética , Fluoresceínas/química , Fluorescência , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/genética , Limite de Detecção , MicroRNAs/genética , Hibridização de Ácido Nucleico , Espectrometria de Fluorescência
6.
ACS Appl Mater Interfaces ; 13(24): 27825-27835, 2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34124898

RESUMO

Simultaneous imaging, diagnosis, and therapy can offer an effective strategy for cancer treatment. However, the complex probe design, poor drug release efficiency, and multidrug resistance remain tremendous challenges to cancer treatment. Here, a novel one-two-three system is built for enhanced imaging and detection of miRNA-21 (miR-21) overexpressed in cancer cell and chemogene therapy. The system consists of dual-mode DNA robot nanoprobes assembled by two types of hairpin DNAs and three-way branch DNAs modified on gold nanoparticles, with intercalating anticancer drugs (doxorubicin), into DNA duplex GC base pairs. In the system, via intracellular ATP-accelerated cyclic reaction triggered by miR-21, fluorescence and SERS signals were alternated with DNA structure switch, and the precise SERS detection of miRNA and fluorescence imaging oriented "on-demand" release of two types of anticancer drugs (anti-miR-21 and Dox) are achieved. Thus, "one-two-three" means one kind of miR-21-triggered endogenous substance accelerated cyclic reaction, two modes of signal switch, and three functions including enhanced imaging, detection, and comprehensive treatment. The one-two-three system has some notable merits. First, ATP as an endogenous substance promotes DNA structure switching and accelerates the cyclic reaction. Second, the treatment with a dual-mode signal switch is more reliable and accurate and can provide more abundant information than a single-mode treatment platform. Thus, the imaging and detection of intracellular miRNA and effective comprehensive therapy are realized. In vivo results indicate that the system can provide new insights and strategies for diagnosis and therapy.


Assuntos
Antineoplásicos/uso terapêutico , Doxorrubicina/uso terapêutico , Corantes Fluorescentes/química , Nanopartículas Metálicas/química , MicroRNAs/análise , Neoplasias/tratamento farmacológico , Trifosfato de Adenosina/química , Animais , Apoptose/efeitos dos fármacos , Aptâmeros de Nucleotídeos/química , DNA/química , DNA/genética , Sondas de DNA/química , Sondas de DNA/genética , Feminino , Humanos , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/genética , Limite de Detecção , Células MCF-7 , Camundongos , MicroRNAs/genética , Hibridização de Ácido Nucleico , Análise Espectral Raman
7.
Carbohydr Polym ; 266: 118111, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-34044928

RESUMO

Herein, a novel targeted delivery system was developed for intracellular co-delivery of doxorubicin (DOX) as a chemotherapeutic drug, antimiR-21 as an oncogenic antagomiR. In this system, DOX was loaded into mesoporous silica nanoparticles (MSNs) and chitosan was applied to cover the surface of MSNs. AS1411 aptamer as targeting nucleolin and antimiR-21 were electrostatically attached onto the surface of the chitosan-coated MSNs and formed the final nanocomplex (AACS nanocomplex). The study of drug release was based on DOX release under pH 7.4 and 5.5. Cellular toxicity and cellular uptake assessments of AACS nanocomplex were carried out in nucleolin positive (C26, MCF-7, and 4T1) and nucleolin negative (CHO) cell lines using MTT assay and flow cytometry analysis, respectively. Also, Anti-tumor efficacy of AACS nanocomplex was evaluated in C26 tumor-bearing mice. Overall, the results show that the combination therapy of DOX and antimiR-21, using AACS nanocomplex, could combat the cancer cell growth rate.


Assuntos
Antagomirs/uso terapêutico , Antineoplásicos/uso terapêutico , Doxorrubicina/uso terapêutico , Portadores de Fármacos/química , Nanopartículas/química , Neoplasias/tratamento farmacológico , Animais , Antagomirs/química , Antagomirs/toxicidade , Antineoplásicos/química , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/toxicidade , Células CHO , Linhagem Celular Tumoral , Quitosana/química , Quitosana/toxicidade , Cricetulus , Doxorrubicina/química , Portadores de Fármacos/toxicidade , Liberação Controlada de Fármacos , Humanos , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/toxicidade , Camundongos , MicroRNAs/antagonistas & inibidores , Nanopartículas/toxicidade , Oligodesoxirribonucleotídeos/química , Oligodesoxirribonucleotídeos/toxicidade , Dióxido de Silício/química , Dióxido de Silício/toxicidade
8.
Methods Mol Biol ; 2282: 101-118, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33928572

RESUMO

GalNAc oligonucleotide conjugates demonstrate improved potency in vivo due to selective and efficient delivery to hepatocytes in the liver via receptor-mediated endocytosis. GalNAc-siRNA and GalNAc-antisense oligonucleotides are at various stages of clinical trials, while the first two drugs were already approved by FDA. Also, GalNAc conjugates are excellent tools for functional genomics and target validation in vivo. The number of GalNAc residues in a conjugate is crucial for delivery as cooperative interaction of several GalNAc residues with asialoglycoprotein receptor enhances delivery in vitro and in vivo. Here we provide a robust protocol for the synthesis of triple GalNAc CPG solid support and GalNAc phosphoramidite, synthesis and purification of RNA conjugates with multiple GalNAc residues either to 5'-end or 3'-end and siRNA duplex formation.


Assuntos
Acetilgalactosamina/síntese química , Ácidos Nucleicos Imobilizados/síntese química , Oligodesoxirribonucleotídeos/síntese química , Compostos Organofosforados/síntese química , RNA Interferente Pequeno/síntese química , Acetilgalactosamina/análogos & derivados , Projetos de Pesquisa , Fluxo de Trabalho
9.
Food Chem Toxicol ; 152: 112201, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33862122

RESUMO

Aflatoxin B1 (AFB1) is one of the most potent mycotoxin contaminating several foods and feeds. It suppresses immunity and consequently increases mutagenicity, carcinogenicity, teratogenicity, hepatotoxicity, embryonic toxicity and increasing morbidity and mortality. Continuous exposure of AFB1 causes liver damage and thus increases the prevalence of cirrhosis and hepatic cancer. This article was planned to provide understanding of AFB1 toxicity and provides future directions for fabrication of cost effective and user-friendly nanomaterials based analytical devices. In the present article various conventional (chromatographic & spectroscopic), modern (PCR & immunoassays) and nanomaterials based biosensing techniques (electrochemical, optical, piezoelectrical and microfluidic) are discussed alongwith their merits and demerits. Nanomaterials based amperometric biosensors are found to be more stable, selective and cost-effective analytical devices in comparison to other biosensors. But many unresolved issues about their stability, toxicity and metabolic fate needs further studies. In-depth studies are needed for development of advanced nanomaterials integrated biosensors for specific, sensitive and fast monitoring of AFB1 toxicity in foods. Integration of biosensing system with micro array technology for simultaneous and automated detection of multiple AFs in real samples is also needed. Concerted efforts are also required to reduce their possible hazardous consequences of nanomaterials based biosensors.


Assuntos
Aflatoxina B1/análise , Técnicas Biossensoriais/métodos , Contaminação de Alimentos/análise , Micotoxinas/análise , Nanoestruturas/química , Aflatoxina B1/química , Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/instrumentação , Ácidos Nucleicos Imobilizados/química , Micotoxinas/química , Testes Imediatos
10.
Angew Chem Int Ed Engl ; 60(21): 11983-11990, 2021 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-33682283

RESUMO

There is considerable interest in the development of libraries of scaffold-diverse macrocycles as a source of ligands for difficult targets, such as protein-protein interaction surfaces. A classic problem in the synthesis of high-quality macrocyclic libraries is that some linear precursors will cyclize efficiently while some will not, depending on their conformational preferences. We report here a powerful quality control method that can be employed to readily distinguish between scaffolds that do and do not cyclize efficiently during solid-phase synthesis of thioether macrocycles without the need for tedious liquid chromatography/mass spectrometry analysis. We demonstrate that this assay can be employed to identify linear impurities in a DNA-encoded library of macrocycles. We also use the method to establish a useful quality control protocol for re-synthesis of putative macrocyclic screening hits.


Assuntos
DNA/química , Ácidos Nucleicos Imobilizados/química , Compostos Macrocíclicos/síntese química , Técnicas de Síntese em Fase Sólida/métodos , Ciclização , Sulfetos/síntese química
11.
Langmuir ; 37(11): 3428-3437, 2021 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-33689355

RESUMO

Over the past 20 years, single-molecule methods have become extremely important for biophysical studies. These methods, in combination with new nanotechnological platforms, can significantly facilitate experimental design and enable faster data acquisition. A nanotechnological platform, which utilizes a flow-stretch of immobilized DNA molecules, called DNA Curtains, is one of the best examples of such combinations. Here, we employed new strategies to fabricate a flow-stretch assay of stably immobilized and oriented DNA molecules using a protein template-directed assembly. In our assay, a protein template patterned on a glass coverslip served for directional assembly of biotinylated DNA molecules. In these arrays, DNA molecules were oriented to one another and maintained extended by either single- or both-end immobilization to the protein templates. For oriented both-end DNA immobilization, we employed heterologous DNA labeling and protein template coverage with the antidigoxigenin antibody. In contrast to single-end immobilization, both-end immobilization does not require constant buffer flow for keeping DNAs in an extended configuration, allowing us to study protein-DNA interactions at more controllable reaction conditions. Additionally, we increased the immobilization stability of the biotinylated DNA molecules using protein templates fabricated from traptavidin. Finally, we demonstrated that double-tethered Soft DNA Curtains can be used in nucleic acid-interacting protein (e.g., CRISPR-Cas9) binding assay that monitors the binding location and position of individual fluorescently labeled proteins on DNA.


Assuntos
DNA , Imagem Individual de Molécula , Ácidos Nucleicos Imobilizados , Nanotecnologia , Proteínas
12.
BMC Res Notes ; 14(1): 106, 2021 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-33743816

RESUMO

OBJECTIVE: Silica gel beads have promise as a non-toxic, cost-effective, portable method for storing environmental DNA (eDNA) immobilized on filter membranes. Consequently, many ecological surveys are turning to silica bead filter desiccation rather than ethanol preservation. However, no systematic evaluation of silica bead storage conditions or duration past 1 week has been published. The present study evaluates the quality of filter-immobilized eDNA desiccated with silica gel under different storage conditions for over a year using targeted quantitative real-time polymerase chain reaction (qPCR)-based assays. RESULTS: While the detection of relatively abundant eDNA target was stable over 15 months from either ethanol- or silica gel-preserved filters at - 20 and 4 °C, silica gel out-performed ethanol preservation at 23 °C by preventing a progressive decrease in eDNA sample quality. Silica gel filter desiccation preserved low abundance eDNA equally well up to 1 month regardless of storage temperature (18, 4, or - 20 °C). However only storage at - 20 °C prevented a noticeable decrease in detectability at 5 and 12 months. The results indicate that brief storage of eDNA filters with silica gel beads up to 1 month can be successfully accomplished at a range of temperatures. However, longer-term storage should be at - 20 °C to maximize sample integrity.


Assuntos
DNA Ambiental , Dessecação , Ácidos Nucleicos Imobilizados , Preservação Biológica , Dióxido de Silício
13.
Chem Commun (Camb) ; 57(21): 2629-2632, 2021 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-33587067

RESUMO

In this work, we have developed a simple and reliable platform for simultaneous analysis of telomerase and miRNA. A three-dimensional bipedal DNA walking strategy is designed utilizing gold nanoparticles and MnO2 nanosheets. Given the merits of fast, sensitive and selective analysis, the developed method has great potential application in early clinical diagnosis.


Assuntos
DNA Catalítico/química , Lógica , MicroRNAs/análise , Espectrometria de Fluorescência/métodos , Telomerase/análise , Sondas de DNA/química , Sondas de DNA/genética , DNA Catalítico/genética , Ouro/química , Células HeLa , Humanos , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/genética , Compostos de Manganês/química , Nanopartículas Metálicas/química , MicroRNAs/genética , Microscopia Confocal , Microscopia de Fluorescência , Conformação de Ácido Nucleico , Hibridização de Ácido Nucleico , Óxidos/química
14.
ACS Appl Mater Interfaces ; 13(8): 9542-9560, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33595277

RESUMO

In the past decades, various nanomaterials with unique properties have been explored for bioapplications. Meanwhile, aptamers, generated from the systematic evolution of ligands by exponential enrichment technology, are becoming an indispensable element in the design of functional nanomaterials because of their small size, high stability, and convenient modification, especially endowing nanomaterials with recognition capability to specific targets. Therefore, the incorporation of aptamers into nanomaterials offers an unprecedented opportunity in the research fields of diagnostics and therapeutics. Here, we focus on recent advances in aptamer-embedded nanomaterials for bioapplications. First, we briefly introduce the properties of nanomaterials that can be functionalized with aptamers. Then, the applications of aptamer-embedded nanomaterials in cellular analysis, imaging, targeted drug delivery, gene editing, and cancer diagnosis/therapy are discussed. Finally, we provide some perspectives on the challenges and opportunities that have arisen from this promising area.


Assuntos
Aptâmeros de Nucleotídeos/química , Ácidos Nucleicos Imobilizados/química , Nanopartículas Metálicas/química , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Animais , Antineoplásicos/uso terapêutico , Sequência de Bases , Portadores de Fármacos/química , Humanos , Hidrogéis/química , Lipossomos/química , Estruturas Metalorgânicas/química , Micelas , Nanoporos
15.
Org Biomol Chem ; 19(9): 1965-1969, 2021 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-33599664

RESUMO

Herein, we present a gold nanoparticle (GNP)-based DNA nanosensor to detect the formation of an i-motif from the random coil structure by small molecules at physiological pH. The nanosensor shows a distance dependent fluorescence turn-off response in the presence of a ligand, indicating conformational changes from the C-rich single stranded DNA into an i-motif.


Assuntos
Técnicas Biossensoriais/métodos , DNA/análise , Ligantes , Nanopartículas Metálicas/química , Conformação de Ácido Nucleico/efeitos dos fármacos , Benzotiazóis/química , DNA/química , DNA/efeitos dos fármacos , Doxorrubicina/química , Corantes Fluorescentes/química , Ouro/química , Ácidos Nucleicos Imobilizados/química , Espectrometria de Fluorescência
16.
ChemistryOpen ; 10(4): 408-413, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33605540

RESUMO

A novel method for the preparation of antitumor drug vehicles has been optimized. Biological materials of chitosan oligosaccharide (CO) and γ-polyglutamic acid (γ-PGA) have previously been employed as modifiers to covalently modify graphene oxide (GO), which in turn loaded doxorubicin (DOX) to obtain a nano drug delivery systems of graphene oxide based composites (GO-CO-γ-PGA-DOX). The system was not equipped with the ability of initiative targeting, thus resulting into toxicity and side effects on normal tissues or organs. In order to further improve the targeting property of the system, the nucleic acid aptamer NH2 -AS1411 (APT) of targeted nucleolin (C23) was used to conjugate on GO-CO-γ-PGA to yield the targeted nano drug delivery system APT-GO-CO-γ-PGA. The structure, composition, dispersion, particle size and morphology properties of the synthesized complex have been studied using multiple characterization methods. Drug loading and release profile data showed that APT-GO-CO-γ-PGA is provided with high drug loading capacity and is capable of controlled and sustained release of DOX. Cell experimental results indicated that since C23 was overexpressed on the surface of Hela cells but not on the surface of Beas-2B cells, APT-GO-CO-γ-PGA-DOX can target Hela cells and make increase toxicity to Hela cells than Beas-2B cells, and the IC50 value of APT-GO-CO-γ-PGA-DOX was 3.23±0.04 µg/mL. All results proved that APT-GO-CO-γ-PGA can deliver antitumor drugs in a targeted manner, and achieve the effect of reducing poison, which indicated that the targeted carrier exhibits a broad application prospect in the field of biomedicine.


Assuntos
Antineoplásicos/farmacologia , Aptâmeros de Nucleotídeos/química , Doxorrubicina/farmacologia , Portadores de Fármacos/química , Grafite/química , Nanocompostos/química , Oligodesoxirribonucleotídeos/química , Aptâmeros de Nucleotídeos/toxicidade , Quitina/análogos & derivados , Quitina/química , Quitina/toxicidade , Portadores de Fármacos/toxicidade , Liberação Controlada de Fármacos , Grafite/toxicidade , Células HeLa , Humanos , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/toxicidade , Nanocompostos/toxicidade , Oligodesoxirribonucleotídeos/toxicidade , Ácido Poliglutâmico/análogos & derivados , Ácido Poliglutâmico/química , Ácido Poliglutâmico/toxicidade
17.
Mikrochim Acta ; 188(1): 7, 2021 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-33389193

RESUMO

A sensing platform is presented for the determination of alkaline phosphatase (ALP) activity based on the cooperation of DNAzyme-Au spherical nucleic acid nanoprobe with the graphene-oxide-loaded hybridization chain reaction (HCR/GO) system to achieve good detection sensitivity and specificity. This assay takes advantage of the strong affinity of pyrophosphate (PPi) to Cu2+ ions and the fact that ALP can hydrolyze pyrophosphate (PPi) to release free Cu2+ ions. In the presence of ALP, the released Cu2+ can promote the Cu2+-dependent DNAzyme to cleave the substrate that generates a shorter DNA fragment, which is responsible for further triggering the HCR/GO system to form a long fluorescence dsDNA and thereby giving an amplified fluorescence signal. Linear calibration range was obtained from 0.2 to 10 U L-1, and the limit of detection (LOD) is about 0.14 U L-1. The feasibility of the proposed method was validated by spiking ALP standards in bovine serum. The recovery ranged from 97.2 to 104.6%, and a coefficient of variation (CV) of less than 8% (n = 3) was obtained. This assay strategy was also applied to evaluate the ALP inhibitor efficiency, which indicates that the assay has potential for drug screening.


Assuntos
Fosfatase Alcalina/sangue , DNA Catalítico/química , Grafite/química , Nanopartículas Metálicas/química , Fosfatase Alcalina/química , Animais , Bovinos , Cobre/química , Difosfatos/química , Ouro/química , Humanos , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Técnicas de Amplificação de Ácido Nucleico/métodos , Espectrometria de Fluorescência/métodos
18.
Mikrochim Acta ; 188(1): 23, 2021 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-33404751

RESUMO

A "signal off" aptasensor has been developed to detect deoxynivalenol (DON). DON aptamers (Apt) were used as biological recognition elements, nickel ferrite nanotubes (NiFe2O4 NTs) are used as the base material to increase the surface area of the electrode, and the Au@Pt NRs were used as carriers for loading signal labels thionine (Thi) and complementary strand (cDNA). In the presence of DON it will be specifically captured by Apt, then the competition mechanism was triggered; the signal molecules fall off from the electrode surface, which then causes the electrode signal to decrease. NiFe2O4 NTs and Au@Pt NRs were characterized by transmission electron microscope (TEM), scanning electron micrograph (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The designed sensor provides a concentration range of 1 × 10-8 to 5 × 10-4 mg mL-1 and limit of detection of 3.02 × 10-9 mg mL-1. Determination of DON in corn meal samples was investigated and the recovery was 98.4 to 103.5%. The proposed aptasensor displayed good sensitivity, high specificity, and acceptable reproducibility. Graphical abstract Based on NiFe2O4 NTs as substrate material and Au@Pt NRs as signal label prepared DON aptasensor for the determination of DON.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Compostos Férricos/química , Nanotubos/química , Níquel/química , Tricotecenos/análise , DNA Complementar/química , Grão Comestível/química , Farinha , Contaminação de Alimentos/análise , Ouro/química , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Fenotiazinas/química , Platina/química , Reprodutibilidade dos Testes , Zea mays/química
19.
Mikrochim Acta ; 188(1): 22, 2021 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-33404928

RESUMO

An electrochemical aptasensor, including the polyethyleneimine-graphite-like carbon nitride/Au nanowire nanocomposite (PEI-C3N4/AuNWs) and exonuclease-assisted signal amplification strategy was constructed for the determination of chloramphenicol (CAP). Initially, a nanocomposite with substantial electrocatalytic property was synthesized by PEI-C3N4/AuNWs. This improves the conductivity and specific surface area of the PEI-C3N4/AuNW-modified gold electrode. Next, a DNA with a complementary sequence to a CAP aptamer (cDNA) was immobilized on the PEI-C3N4/AuNW-modified electrode, followed by the CAP aptamer hybridized with cDNA. The lower signal at this time is due to the negatively charged phosphate group of the oligonucleotide and [Fe (CN)6]3-/4- electrostatically repelling each other. The presence of the CAP would cause aptamer on the electrode surface to fall off and be digested by Recjf exonuclease, which resulted in target recycling, and a significant increase in DPV signal can be observed at a potential of 0.176 V (vs. Ag/AgCl). Under optimal conditions, there is a linear relationship between the peak current and the logarithm of CAP concentration in the range 100 fM-1 µM, and the detection limit of this aptasensor is 2.96 fM (S/N = 3). Furthermore, the resultant aptasensor has excellent specificity, reproducibility, and long-term stability, and has been applied to the detection of CAP in milk samples. Graphical abstract The detection principle of the electrochemical aptasensor for CAP detection was based on PEI-C3N4/AuNWs and exonuclease-assistant signal amplification. It is based on the fact that PEI-C3N4/AuNWs nanocomposites on the surface of the electrode can effectively improve the performance of the aptasensor, and Recjf exonuclease initiates the target recycling process, causes signal amplification.


Assuntos
Aptâmeros de Nucleotídeos/química , Cloranfenicol/análise , Exonucleases/química , Nanofios/química , Animais , Técnicas Biossensoriais/métodos , Cloranfenicol/química , Técnicas Eletroquímicas/métodos , Eletrodos , Contaminação de Alimentos/análise , Ouro/química , Grafite/química , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Leite/química , Compostos de Nitrogênio/química , Polietilenoimina/química , Reprodutibilidade dos Testes , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
20.
Mikrochim Acta ; 188(2): 31, 2021 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-33415459

RESUMO

A novel and relatively simple signal-off electrochemical aptasensor was constructed for highly sensitive detection of lipopolysaccharide (LPS). For the first time, silver nanoparticles (AgNPs) decorated titanium dioxide nanotube (TNT) was conjugated with polydiallyldimethylammonium chloride (PDDA) functionalized reduced graphene oxide (rGO) to form a new nanohybrid of Ag-TNT/P-rGO. This nanohybrid with a large specific surface area exhibited excellent electrochemical activity, which not only served as the sensing platform to immobilize LPS binding aptamer (LBA) but was also employed as the redox probe to monitor the change of the electrochemical signal. The electrochemical signal responses were measured by cyclic voltammetry (CV) in the potential range -0.3 to 0.5 V at a scan rate of 0.1 V/s. The proposed aptasensor exhibited acceptable stability, reproducibility, and specificity for LPS detection with a wide linear range from 17 fg/mL to 100 ng/mL. The limit of detection (LOD) was 5 fg/mL. Furthermore, the prepared aptasensor showed acceptable recovery ranging from 96% to 103%, and the RSD varied between 1.4% and 8.5% for determining LPS in real samples.Graphical abstract.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Técnicas Eletroquímicas/métodos , Lipopolissacarídeos/análise , Nanopartículas Metálicas/química , Nanotubos/química , Sequência de Bases , DNA/química , Grafite/química , Ácidos Nucleicos Imobilizados/química , Limite de Detecção , Lipopolissacarídeos/química , Oxirredução , Preparações Farmacêuticas/análise , Preparações Farmacêuticas/química , Polietilenos/química , Compostos de Amônio Quaternário/química , Reprodutibilidade dos Testes , Prata/química , Titânio/química
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