RESUMO
A label-free ultrasensitive electrochemical aptameric sensor which combined the advantages of an aptamer and hyperbranched rolling circle amplification (HRCA) has been developed for specific recognition of a platelet-derived growth factor B-chain (PDGF-BB).
Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Eletroquímicas , Proteínas Proto-Oncogênicas c-sis/análise , Becaplermina , Benzenossulfonatos/química , Técnicas Biossensoriais , Linhagem Celular Tumoral , DNA Complementar/química , Eletrodos , HumanosRESUMO
A novel fluorescent aptameric sensor for thrombin has been developed by combination of the high amplification efficiency of HRCA and the specific function of aptameric recognition.
Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Biossensoriais/métodos , Corantes Fluorescentes/química , Proteínas/análise , Humanos , Trombina/análiseRESUMO
A novel, highly sensitive and selective dual-readout sensor (colorimetric and fluorometric) for the detection of lysozyme was proposed. The fluorescence of triazolylcoumarin molecules was quenched by Au nanoparticles (AuNPs) initially through the fluorescence resonance energy transfer (FRET), after the addition of lysozyme, the stronger binding of lysozyme onto the surfaces of AuNPs made triazolylcoumarin molecules remove from the AuNPs surface and led to the recovery of the fluorescence of triazolylcoumarin molecules, and accompanied by the discernable color change of the solution from red to purple. The lowest detectable concentration for lysozyme was 50 ng mL(-1) by the naked eye, and the limit of detection (LOD) was 23 ng mL(-1) by fluorescence measurements. In addition, satisfactory results for lysozyme detection in hen egg white were confirmed in the study. Moreover, the presented sensor provides a reliable option to determine lysozyme with high sensitivity and selectivity.
Assuntos
Técnicas Biossensoriais/métodos , Fluorometria/métodos , Muramidase/análise , Animais , Galinhas , Colorimetria/métodosRESUMO
A simple, cost-efficient, sensitive and selective fluorescence sensor is developed for sequence-specific recognition of duplex DNA (ds-DNA) in vitro using metal-organic framework (MOF) as the sensing platform. N,N-Bis(2-hydroxy-ethyl)dithiooxamidatocopper(II) (H(2)dtoaCu) was chosen as the example MOF, because it strongly chemisorbs the dye-labeled probe TFO (triplex-forming oligonucleotide), and quenches fluorescence from the dye. In the presence of target ds-DNA (the PPT of HIV RNA, a 16-bp ds-DNA sequence), the TFO could interact with the major groove in ds-DNA (via Hoogsteen hydrogen bonding) to form a rigid triplex structure, resulting in fluorescence recovery. The enhanced fluorescence signal has a relationship with the ds-DNA concentration, the detection limit is as low as 1.3 nmol L(-1) (S/N = 3) with good selectivity, which is lower than that based on a graphene oxide platform and electrochemical-DNA sensor.
Assuntos
Técnicas Biossensoriais/métodos , DNA/análise , DNA/genética , Compostos Organometálicos/química , Sequência de Bases , Cobre/química , DNA/química , Modelos Moleculares , Conformação de Ácido Nucleico , Hibridização de Ácido Nucleico , Especificidade por SubstratoRESUMO
The metal-organic framework (MOF) was first utilized as the sensing platform for assaying biomolecules. It has also been demonstrated that this novel strategy is effective and reliable for detection of HIV DNA and thrombin with high sensitivity and selectivity.
Assuntos
Técnicas de Química Analítica/instrumentação , DNA Viral/análise , Compostos Organometálicos/química , Trombina/análise , Cobre/química , DNA Viral/química , HIV-1 , Modelos Moleculares , Conformação Molecular , Trombina/químicaRESUMO
A novel colorimetric switch based on the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction has been developed. G-quadruplex-hemin DNAzyme catalyzes the oxidation of 2,2'-azinobis(3-ethylbenzothiozoline)-6-sulfonic acid (ABTS) to form ABTSË(+), the UV absorbance of the solution increased greatly and the color of the solution changed to dark green. However, in the presence of an azide complex, the absorbance signal decreased and the solution became light green since the catalytic ability of the hemin was inhibited by the azide groups. However, once propargylamine has been added into the above reaction system, which would react with azide groups through the CuAAC reaction, the solution becomes dark green again and the absorption intensity of the system is also increased. The proposed switch allows a good reversibility and can be identified clearly by the naked eye. In addition, the method has been applied to detect some pesticides, which have alkynyl groups (flumioxazin), with high sensitivity and selectivity, where the UV absorbance has a direct linear relationship with the logarithm of flumioxazin concentrations in the range of 0.14-14 nM, and the limit of detection was 0.056 nM (S/N = 3), which can meet the requirement of the maximum residue limits (MRLs) of United States of America (56 nM).
