RESUMO
Restricted target accessibility and surface-induced perturbation of the aptamer structure are the main limitations in single-stranded DNA aptamer-based electrochemical sensors. Chemical labeling of the aptamer with a probe at the end of aptamer is inefficient and time-consuming. In this work, tetrahedron-structured DNA (ts-DNA) and a functionalized oligonucleotide (FO) were used to develop an electrochemiluminescence (ECL) aptasensor with adenosine triphosphate (ATP) as a model target. The ts-DNA was formed with three thiolated oligonucleotides and one oligonucleotide containing anti-ATP aptamer. The FO contained a complementary strand to the anti-ATP aptamer and an intermolecular duplex for Ru(phen)3(2+) intercalation. After the ts-DNA was immobilized on the electrode surface through gold-thiol interactions, hybridization between the anti-ATP aptamer and its complementary strand introduced the intercalated Ru(phen)3(2+) to the electrode. ECL emission from Ru(phen)3(2+) was observed with tripropylamine as a co-reactant. Once ATP reacted with its aptamer, the aptamer-complimentary strand duplex dissociated and the intermolecular duplex containing Ru(phen)3(2+) was released. The difference in emission before and after reaction with ATP was used to quantify ATP with a detection limit of 0.2nM. The ts-DNA increased the sensitivity compared to conventional methods, and the intercalation strategy avoided a complex chemical labeling procedure.
Assuntos
Trifosfato de Adenosina/análise , Técnicas Biossensoriais/instrumentação , Condutometria/instrumentação , DNA/química , DNA/ultraestrutura , Medições Luminescentes/instrumentação , Rubídio/química , Desenho de Equipamento , Análise de Falha de Equipamento , Substâncias Intercalantes/químicaRESUMO
An electrochemiluminescent biosensor was designed for the detection of Ag(+) ions and cysteine as well as their interaction study. To this end, a functional nucleic acid was designed for target recognition and probe intercalation.
Assuntos
Técnicas Biossensoriais , Cisteína/análise , DNA/química , Prata/análise , Complexos de Coordenação/química , Glutationa/química , Íons/química , Medições Luminescentes , Rutênio/químicaRESUMO
Tetrahedron-structured DNA (ts-DNA) in combination with a functionalized oligonucleotide was used to develop a "turn-on" biosensor for Hg(2+) ions. The ts-DNA provided an improved sensitivity and was used to block the active sites.