A label-free aptamer-fluorophore assembly for rapid and specific detection of cocaine in biofluids.
Anal Chem
; 86(22): 11100-6, 2014 Nov 18.
Article
em En
| MEDLINE
| ID: mdl-25342426
ABSTRACT
We report a rapid and specific aptamer-based method for one-step cocaine detection with minimal reagent requirements. The feasibility of aptamer-based detection has been demonstrated with sensors that operate via target-induced conformational change mechanisms, but these have generally exhibited limited target sensitivity. We have discovered that the cocaine-binding aptamer MNS-4.1 can also bind the fluorescent molecule 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND) and thereby quench its fluorescence. We subsequently introduced sequence changes into MNS-4.1 to engineer a new cocaine-binding aptamer (38-GC) that exhibits higher affinity to both ligands, with reduced background signal and increased signal gain. Using this aptamer, we have developed a new sensor platform that relies on the cocaine-mediated displacement of ATMND from 38-GC as a result of competitive binding. We demonstrate that our sensor can detect cocaine within seconds at concentrations as low as 200 nM, which is 50-fold lower than existing assays based on target-induced conformational change. More importantly, our assay achieves successful cocaine detection in body fluids, with a limit of detection of 10.4, 18.4, and 36 µM in undiluted saliva, urine, and serum samples, respectively.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Líquidos Corporais
/
Cocaína
/
Aptâmeros de Nucleotídeos
/
Corantes Fluorescentes
/
Naftiridinas
Tipo de estudo:
Diagnostic_studies
Limite:
Humans
Idioma:
En
Revista:
Anal Chem
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Estados Unidos