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1.
Biosens Bioelectron ; 176: 112954, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33412428

RESUMO

CRISPR/Cas system have drawn increasing attention in accurate and sensitive nucleic acids detection. Herein, we reported a novel Cas12a-based electrochemiluminescence biosensor for target amplification-free human papilloma virus subtype (HPV-16) DNA detection. During this detection process, Cas12a employed its two-part recognition mechanism to improve the specificity and trans-cleavage capability to achieve signal amplification, while L-Methionine stabilized gold nanoclusters (Met-AuNCs) were served as high-efficiency ECL emitters to achieve ECL signal transition. Given the unique combination of Cas12a with ECL technique, the detection limit was determined as 0.48 pM and the whole detection could be completed within 70 min. We also validated the practical application of the proposed biosensor by using undiluted human blood samples, which gives impetus to the design of new generations of CRISPR/Cas detection system beyond the traditional ones with ultimate applications in sensing analysis and diagnostic technologies.

2.
Mikrochim Acta ; 186(1): 28, 2018 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-30564953

RESUMO

An aptamer-based fluorometric assay is described for the determination of bisphenol A (BPA). The aptamer against BPA is first attached to the surface of the red AuNPs, and this prevents the AuNPs from salt-induced formation of a blue-colored aggregate. Hence, the blue fluorescence of added nitrogen-doped carbon dots (NCDots) is quenched via an inner filter effect (IFE) caused by the red AuNPs. After addition of BPA, the BPA/aptamer complex is formed, and the AuNPs are no longer stabilized agains aggregation. This weakens the IFE and results in the recovery of the fluorescence of the NCDots which is measured best at excitation/emission wavelengths of 300/420 nm. The recovered fluorescence increases linearly in the 10 to 250 nM and 250 to 900 nM BPA concentration ranges, and the detection limit is 3.3 nM. The method was successfully applied to the determination of BPA in spiked environmental tap water samples. Graphical abstract Schematic presentation of a fluorometric aptamer based assay for bisphenol A (BPA). It is based on the inner filter effect of gold nanoparticles (AuNPs) on the fluorescence of nitrogen-doped carbon dots (NCDots).

3.
Mikrochim Acta ; 185(10): 463, 2018 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-30225568

RESUMO

An electrochemiluminescence (ECL) based assay is described for the determination of the endocrine disruptor bisphenol A (BPA). The method is based on the use of carboxylated graphitic carbon nitride (C-g-C3N4) carrying an immobilized aptamer against BPA. In the presence of BPA, the ECL signal decreases due to ECL energy transfer from excited-state C-g-C3N4 to the BPA oxidation product. Under the optimal conditions, ECL intensity increases linearly in the 0.1 pM to 1 nM BPA concentration range. The detection limit is as low as 30 fM. The assay has excellent sensitivity, outstanding stability and high selectivity. It was applied to the determination of BPA in spiked water samples. Graphical abstract Aptamer modified carboxylated graphitic carbon nitride was synthesized and applied in an electrochemiluminescence-based aptasensor for bisphenol A.


Assuntos
Aptâmeros de Nucleotídeos/metabolismo , Compostos Benzidrílicos/análise , Grafite/química , Limite de Detecção , Medições Luminescentes , Nitrilos/química , Fenóis/análise , Calibragem , Ácidos Carboxílicos/química , Eletroquímica , Modelos Moleculares , Conformação Molecular
4.
Analyst ; 138(2): 666-70, 2013 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-23181261

RESUMO

Hsp70 proteins are implicated in resistance to chemotherapy in cancers, the detection of which is important for cancer treatment and prognosis. In this work, we report the study on the detection of specific intracellular target protein in fixed cells using GlcNAc-conjugated CdSeTe QDs. The QDs were coupled with Con A via a carbodiimide reaction and then were further assembled with GlcNAc by lectin-carbohydrate interaction between Con A and GlcNAc. The obtained QDs-Con A-GlcNAc conjugates have an emission wavelength at 650 nm that is close to the near-infrared (NIR) regions and a specific recognition for Hsp70. These results show that the QDs-Con A-GlcNAc probe can be a promising tool for direct localization of the Hsp70 protein.


Assuntos
Acetilglucosamina/metabolismo , Concanavalina A/metabolismo , Proteínas de Choque Térmico HSP70/análise , Pontos Quânticos , Acetilglucosamina/química , Cádmio/química , Linhagem Celular Tumoral , Concanavalina A/química , Proteínas de Choque Térmico HSP70/química , Células HeLa , Humanos , Microscopia Confocal , Microscopia de Fluorescência , Selênio/química , Telúrio/química
5.
Chem Commun (Camb) ; 46(17): 2974-6, 2010 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-20386841

RESUMO

New water-soluble CdSeTe/ZnS core-shell quantum dots with excellent near-infrared emission were synthesized via an aqueous solution method; they showed strong electrogenerated chemiluminescence and favorable biocompatibility.


Assuntos
Compostos de Cádmio/química , Pontos Quânticos , Compostos de Selênio/química , Telúrio/química , Sulfato de Zinco/química , Eletrodos , Ouro/química , Medições Luminescentes , Espectroscopia de Luz Próxima ao Infravermelho
6.
Talanta ; 80(5): 2172-6, 2010 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-20152468

RESUMO

The near-infrared (NIR)-emitting CdSeTe alloyed quantum dots (AQdots) that capped with L-cysteine were applied for ultrasensitive Cu(2+) sensing. The sensing approach was based on the fluorescence of the AQdots selectively quenched in the presence of Cu(2+). Experimental results showed a low interference response towards other metal ions. The possible quenching mechanism was discussed on the basis of the binding between L-cysteine and the metal ions. In addition, biomolecules have low effect on the fluorescence due to the minimized interferences in NIR region. The response of the NIR optical sensor was linearly proportional to the concentration of Cu(2+) ranging from 2 x 10(-8) to 2 x 10(-6) mol L(-1). Furthermore, it has been successfully applied to the detection of Cu(2+) in vegetable samples.


Assuntos
Cobre/análise , Pontos Quânticos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Ligas/química , Cádmio/química , Cisteína/química , Fluorescência , Selênio/química , Sensibilidade e Especificidade , Telúrio/química , Verduras/química
7.
Nanotechnology ; 20(41): 415103, 2009 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-19762946

RESUMO

A facile method is developed for the preparation of high-quality, water-soluble, and near-infrared (NIR)-emitting CdSeTe alloyed quantum dots (AQdots) with L-cysteine as the capping agent. By changing the size and the composition of AQdots the photoluminescent quantum yield (QY) can reach as high as 53% and the emission color can be tuned between visible and NIR regions (580-814 nm). Furthermore, the prepared NIR-emitting AQdots have been successfully applied for HL-60 cell imaging and glucose and cholesterol assay, which demonstrates the great potential of the AQdots for biological applications.


Assuntos
Ligas/química , Cádmio/química , Diagnóstico por Imagem/métodos , Nanotecnologia/métodos , Pontos Quânticos , Selênio/química , Telúrio/química , Ligas/síntese química , Células HL-60 , Humanos
8.
Biosens Bioelectron ; 24(12): 3693-7, 2009 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-19493671

RESUMO

A novel sensing system based on the near infrared (NIR) fluorescence resonance energy transfer (FRET) between Mn:CdTe quantum dots (Qdots) and Au nanorods (AuNRs) was established for the detection of human IgG. The NIR-emitting Qdots linked with goat anti-human IgG (Mn:CdTe-Ab1) and AuNRs linked with rabbit anti-human IgG (AuNRs-Ab2) acted as fluorescence donors and acceptors, respectively. FRET occurred by human IgG with the specific antigen-antibody interaction. And human IgG was detected based on the modulation in FRET efficiency. The calibration graph was linear over the range of 0.05-2.5 microM of human IgG under optimal conditions. The proposed sensing system can decrease the interference of biomolecules in NIR region and increase FRET efficiency in optimizing the spectral overlap of AuNRs with Mn:CdTe Qdots. This method has great potential for multiplex assay with different donor-acceptor pairs.


Assuntos
Técnicas Biossensoriais/instrumentação , Compostos de Cádmio/química , Transferência Ressonante de Energia de Fluorescência/instrumentação , Ouro/química , Nanotubos/química , Pontos Quânticos , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Telúrio/química , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Imunoglobulina G/análise , Manganês/química , Nanotecnologia/instrumentação , Nanotubos/ultraestrutura
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