A label-free electrochemiluminescence aptasensor for thrombin based on novel assembly strategy of oligonucleotide and luminol functionalized gold nanoparticles.
In the work, a label-free electrochemiluminescence (ECL) aptasensor for the sensitive and selective detection of thrombin was constructed based on target-induced direct ECL signal change by virtue of a novel assembly strategy of oligonucleotide and luminol functionalized gold nanoparticles (luminol-AuNPs). It is the first label-free ECL biosensor based on luminol and its analogs functionalized AuNPs. Streptavidin AuNPs coated with biotinylated DNA capture probe 1 (AuNPs-probe 1) were firstly assembled onto an gold electrode through 1,3-propanedithiol. Then luminol-AuNPs co-loaded with thiolated DNA capture probe 2 and thiolated thrombin binding aptamer (TBA) (luminol-AuNPs-probe 2/TBA) were assembled onto AuNPs-probe 1 modified electrode through the hybridization between capture probes 1 and 2. The luminol-AuNPs-probe 2/TBA acted as both molecule recognition probe and sensing interface. An Au/AuNPs/ds-DNA/luminol-AuNPs/TBA multilayer architecture was obtained. In the presence of target thrombin, TBA on the luminol-AuNPs could capture the thrombin onto the electrode surface, which produced a barrier for electro-transfer and influenced the electro-oxidation reaction of luminol, leading to a decrease in ECL intensity. The change of ECL intensity indirectly reflected the concentration of thrombin. Thus, the approach showed a high sensitivity and a wider linearity for the detection of thrombin in the range of 0.005-50nM with a detection limit of 1.7pM. This work reveals that luminol-AuNPs are ideal platform for label-free ECL bioassays.
CAS Key Laboratory of Soft Matter Chemistry, Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, PR China.
Fang
F
Li
Hua
H
Cui
D052157:Aptamers, Nucleotide / Q000737:chemistry*; D004867:Equipment Design; D006046:Gold / Q000737:chemistry*; D006801:Humans; D008163:Luminescent Measurements / Q000295:instrumentation*; D008165:Luminol / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D012680:Sensitivity and Specificity; D013917:Thrombin / Q000032:analysis*
D052157:Aptamers, Nucleotide; C081676:thrombin aptamer; D008165:Luminol; D006046:Gold; D013917:Thrombin