Direct fluorescence anisotropy assay for cocaine using tetramethylrhodamine-labeled aptamer.
Anal Bioanal Chem
; 409(16): 3993-4000, 2017 Jun.
Article
em En
| MEDLINE
| ID: mdl-28429063
ABSTRACT
Development of simple, sensitive, and rapid method for cocaine detection is important in medicine and drug abuse monitoring. Taking advantage of fluorescence anisotropy and aptamer, this study reports a direct fluorescence anisotropy (FA) assay for cocaine by employing an aptamer probe with tetramethylrhodamine (TMR) labeled on a specific position. The binding of cocaine and the aptamer causes a structure change of the TMR-labeled aptamer, leading to changes of the interaction between labeled TMR and adjacent G bases in aptamer sequence, so FA of TMR varies with increasing of cocaine. After screening different labeling positions of the aptamer, including thymine (T) bases and terminals of the aptamer, we obtained a favorable aptamer probe with TMR labeled on the 25th base T in the sequence, which exhibited sensitive and significant FA-decreasing responses upon cocaine. Under optimized assay conditions, this TMR-labeled aptamer allowed for direct FA detection of cocaine as low as 5 µM. The maximum FA change reached about 0.086. This FA method also enabled the detection of cocaine spiked in diluted serum and urine samples, showing potential for applications. Graphical Abstract The binding of cocaine to the TMR-labeled aptamer causes conformation change and alteration of the intramolecular interaction between TMR and bases of aptamer, leading to variance of fluorescence anisotropy (FA) of TMR, so direct FA analyis of cocaine is achieved.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Rodaminas
/
Cocaína
/
Aptâmeros de Nucleotídeos
/
Polarização de Fluorescência
/
Corantes Fluorescentes
/
Anestésicos Locais
Limite:
Humans
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article