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1.
Anal Chem ; 93(36): 12329-12336, 2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34474564

RESUMO

"On-demand" accurate imaging of multiple intracellular miRNAs will significantly improve the detection reliability and accuracy. However, the "always-active" design of traditional multicomponent detection probes enables them to passively recognize and output signals as soon as they encounter targets, which will inevitably impair the detection accuracy and, inevitably, result in false-positive signals. To address this scientific problem, in this work, we developed a near-infrared (NIR) light-activated multicomponent detection intelligent nanoprobe for spatially and temporally controlled on-demand accurate imaging of multiple intracellular miRNAs. The proposed intelligent nanoprobe is composed of a rationally designed UV light-responsive triangular DNA nano sucker (TDS) and upconversion nanoparticles (UCNPs), named UCNPs@TDS (UTDS), which can enter cells autonomously through endocytosis and enable remote regulation of on-demand accurate imaging for multiple intracellular miRNAs using NIR light illumination at a chosen time and place. It is worth noting that the most important highlight of the UTDS we designed in this work is that it can resist nonspecific activation as well as effectively avoid false-positive signals and improve the accuracy of imaging of multiple intracellular miRNAs. Moreover, distinguishing different kinds of cell lines with different miRNA expressions levels can be also achieved through this NIR light-activated intelligent UTDS, showing feasible prospects in precise imaging and disease diagnosis.


Assuntos
MicroRNAs , Nanopartículas , DNA , Raios Infravermelhos , Reprodutibilidade dos Testes
2.
Anal Chem ; 93(4): 2480-2489, 2021 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-33410672

RESUMO

Plasmon-enhanced fluorescence (PEF) is considered to be a powerful signal amplification technology to overcome intrinsic shortcomings of photobleaching and brightness of the traditional fluorescent dyes. Nevertheless, exploitation of PEF-based probes for bioimaging application is still at a very early stage. In this work, a simple but powerful gold nanostar (Au NST)@SiO2-based PEF probe with 20 symmetric "hot spots" was developed for highly sensitive "lighting up" in situ imaging of intracellular microRNAs (miRNAs). By regulating the thickness of the silica shell, the distance between Au NSTs and fluorescent dyes was controlled, and the optimum fluorescence enhancement (21-fold) was obtained with the silica shell thickness of approximately 22 nm. Thanks to the 20 more powerful "hot spots" that can produce stronger localized electric fields, the Au NST-based PEF probe exhibits stronger PEF effects than the traditional plasmonic nanostructures such as gold nanorods (Au NRs), gold nanobipyramids (Au NBPs), and triangular gold nanoprisms (Au NPRs), resulting in high sensitivity and improved detection limit (LOD) of 0.21 pM for miRNA-21 analysis. Moreover, not only cancer cells (MCF-7 and Hela) and normal cells (L02) with distinct miRNA-21 expression levels can be discriminated but also tumor cells in co-cultured mixtures can be recognized, indicating its promising potential in clinical diagnosis.

3.
Chem Commun (Camb) ; 56(29): 4074-4077, 2020 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-32159543

RESUMO

In this study, three kinds of CDs with blue, yellow and red emissions were prepared and their luminescence mechanisms through theoretical calculations together with experimental data were further investigated in depth. Afterwards, a sensor array was constructed by using three kinds of CD-metal ions for rapid discrimination of different types of sulfur-containing species.

4.
J Mass Spectrom ; 55(1): e4463, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31671229

RESUMO

Noncovalent interactions between drugs and proteins play significant roles for drug metabolisms and drug discoveries. Mass spectrometry has been a commonly used method for studying noncovalent interactions. However, the harsh ionization process in electrospray ionization mass spectrometry (ESI-MS) is not conducive to the preservation of noncovalent and unstable biomolecular complexes compared with the cold spray ionization mass spectrometry (CSI-MS). A cold spray ionization providing a stable solvation-ionization at low temperature is milder than ESI, which was more suitable for studying noncovalent drug-protein complexes with exact stoichiometries. In this paper, we apply CSI-MS to explore the interactions of ginsenosides toward amyloid-ß-peptide (Aß) and clarify the therapeutic effect of ginsenosides on Alzheimer's disease (AD) at the molecular level for the first time. The interactions of ginsenosides with Aß were performed by CSI-MS and ESI-MS, respectively. The ginsenosides Rg1 bounded to Aß at the stoichiometries of 1:1 to 5:1 could be characterized by CSI-MS, while dehydration products are more readily available by ESI-MS. The binding force depends on the number of glycosyls and the type of ginsenosides. The relative binding affinities were sorted in order as follows: Rg1 ≈ Re > Rd ≈ Rg2 > Rh2, protopanaxatriol by competition experiments, which were supported by molecular docking experiment. CSI-MS is expected to be a more appropriate approach to determine the weak but specific interactions of proteins with other natural products especially polyhydroxy compounds.


Assuntos
Peptídeos beta-Amiloides/química , Ginsenosídeos/química , Simulação de Acoplamento Molecular/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Sítios de Ligação , Ligação Proteica , Sapogeninas/química , Relação Estrutura-Atividade
5.
Anal Chem ; 91(21): 13947-13952, 2019 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-31558029

RESUMO

Gold nanoclusters (Au NCs) coated with various peptides have been widely used as fluorescent probes, and nowadays the most commonly used are cysteine (C) and tyrosine (Y) based ones. Herein, we report the preparation and clinical application of highly efficient and stable fluorescent Au NCs protected by screened peptides with a specific amino acid sequence Cys-Met-Met-Met-Met-Met (CMMMMM). Compared with traditional C, Y based peptide (CYYYYY) protected Au NCs, the fluorescence intensity of the CMMMMM-Au NCs increased by 230%, and the photobleaching resistance or stability of the CMMMMM-Au NCs increased by about 300% (after continuous ultraviolet irradiation for 60 min, the fluorescence of the CMMMMM-Au NCs remained more than 90% of their initial intensity, while the CYYYYY-Au NCs remained less than 30%). Assaying arrays based on CMMMMM protected Au NCs with different positive or negative charges as sensing receptors were developed through regulating different pH values, and multivariate analysis on the patterns obtained by these arrays allowed effective identification of not only ten proteins separately but also complex protein mixtures with subtly diverse compositions. The docking simulation and isothermal titration confirmed that target proteins interacted with CMMMMM-Au NCs mainly through electrostatic interactions and partly hydrophobic interactions, which affected the binding energy and fluorescence lifetime of CMMMMM-Au NCs, resulting in the unique fingerprint-like recognition patterns. Furthermore, serums from breast cancer, severe osteoarthritis, and rectal cancer patients can be effectively identified with healthy people using this CMMMMM-Au NCs based sensor array.


Assuntos
Ouro , Nanopartículas Metálicas/química , Peptídeos/química , Sequência de Aminoácidos , Neoplasias da Mama/diagnóstico , Corantes Fluorescentes/química , Osteoartrite/diagnóstico , Fotodegradação , Proteômica/métodos , Neoplasias Retais/diagnóstico , Eletricidade Estática
6.
J Mater Chem B ; 5(27): 5329-5335, 2017 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32264071

RESUMO

Point mutation, with a permanent change in nucleic acid sequences, can affect the expression of genetic information forming the basis for numerous human genetic diseases, which makes its detection crucially important. Here, we reported a simple and sensitive method for point mutation detection, which employs a core-shell gold nanocube (Au NC) based on plasmon-enhanced fluorescence (PEF). For the generation of PEF, a Au NC was chosen as a core and silica as a spacer layer to adjust the distance between the Au NC and the dye of 5-carboxyfluorescein. Cu2+ quenched fluorescence by the interaction with the dye, while a "turn-on" signal was observed with the presence of pyrophosphate (PPi) owing to the strong affinity between Cu2+ and PPi, which subsequently achieved sensitive and selective detection of PPi. The experiment and theoretical simulations indicated that the enhanced signal was generated from square scattering cross sections and multiple corners, which could also be applied to cell imaging. Moreover, the rolling circle amplification coupled with ligase chain reaction (L-RCA) assay was also performed, which generated a circular DNA to initiate the RCA reaction accompanied by the generation of PPi that can be detected by the PEF sensor. Therefore, point mutation (C to T) can be detected based on fluorescence changes with a detection limit of 1.3 pM. This is a specific, simple, and economical method for point mutation detection, which overcomes the shortcomings of traditional detections of RCA products and point mutation.

7.
Anal Chim Acta ; 776: 24-30, 2013 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-23601277

RESUMO

Based on the polyphosphonate-assisted coacervation of chitosan, a simple and versatile procedure for the encapsulation of proteins/enzymes in chitosan-carbon nanotubes (CNTs) composites matrix was developed. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectrum (EDS) mapping demonstrated the hemoglobin (Hb) uniformly distributed into chitosan-CNTs composites matrix. Raman measurements indicated the CNTs in composites matrix retained the electronic and structural integrities of the pristine CNTs. Fourier transform infrared (FT-IR), ultraviolet-visible (UV-vis) and circular dichroism (CD) spectroscopy displayed the encapsulated Hb preserved their near-native structure, indicating the polyphosphonate-chitosan-CNTs composites possessed excellent biocompatibility for the encapsulation of proteins/enzymes. Electrochemical measurements indicated the encapsulated Hb could directly exchange electron with the substrate electrode. Moreover, the modified electrode showed excellent bioelectrocatalytic activity for the reduction of hydrogen peroxide. Under optimum experimental conditions, the fabricated electrochemical sensor displayed the fast response (less than 3s), wide linear range (7.0×10(-7) to 2.0×10(-3)M) and low detection limit (4.0×10(-7)M) for the determination of hydrogen peroxide. This newly developed protocol was simple and mild and would certainly find extensive applications in biocatalysis, biosensors, bioelectronics and biofuel cells.


Assuntos
Técnicas Biossensoriais , Quitosana/química , Hemoglobinas/metabolismo , Compostos Organofosforados/química , Técnicas Eletroquímicas , Eletrodos , Hemoglobinas/química , Peróxido de Hidrogênio/química , Proteínas Imobilizadas/química , Proteínas Imobilizadas/metabolismo , Nanotubos de Carbono/química
8.
Analyst ; 138(9): 2647-53, 2013 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-23486722

RESUMO

A nonenzymatic iron(III) diethylenetriaminepentaacetic acid (Fe(III)-DETPA) complex based amperometric sensor for the analytical determination of hydrogen peroxide was developed. By combining the electrostatic interaction between the Fe(III)-DETPA complex and polyallylamine (PAH) functionalized multiwalled carbon nanotubes (MWCNTs) as well as the ionotropic crosslinking interaction between PAH and ethylenediamine-tetramethylene phosphonic acid (EDTMP), the electroactive Fe(III)-DETPA complex was successfully incorporated within the MWCNT matrix, and firmly immobilized on the Au substrate electrode. The fabricated electrochemical sensor was characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electrochemical methods. The influences of solution pH and ionic strength on the electrochemical sensor were investigated. The prepared electrochemical sensor had a fast response to hydrogen peroxide (<3 s) and an excellent linear range of concentration from 1.25 × 10(-8) to 4.75 × 10(-3) M with a detection limit of 6.3 × 10(-9) M under the optimum conditions.


Assuntos
Técnicas Eletroquímicas/instrumentação , Compostos Férricos/química , Peróxido de Hidrogênio/análise , Nanotubos de Carbono/química , Ácido Pentético/química , Poliaminas/química , Catálise , Eletrodos , Nanotubos de Carbono/ultraestrutura , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
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