Aptamer-based label-free method for hemin recognition and DNA assay by capillary electrophoresis with chemiluminescence detection

Abstract

An aptamer-based label-free approach to hemin recognition and DNA assay using capillary electrophoresis with chemiluminescence detection is introduced here. Two guanine-rich DNA aptamers were used as the recognition element and target DNA, respectively. In the presence of potassium ions, the two aptamers folded into the G-quartet structures, binding hemin with high specificity and affinity. Based on the G-quartet-hemin interactions, the ligand molecule was specifically recognized with a Kd approximately 73 nM, and the target DNA could be detected at 0.1 microM. In phosphate buffer of pH 11.0, hemin catalyzed the H2O2-mediated oxidation of luminol to generate strong chemiluminescence signal; thus the target molecule itself served as an indicator for the molecule-aptamer interaction, which made the labeling and/or modification of aptamers or target molecules unnecessary. This label-free method for molecular recognition and DNA detection is therefore simple, easy, and effective.

Improved method for chemiluminescent determination of peroxidase-mimicking DNAzyme activity

“…Literature analysis performed by us showed that different experimental conditions were used to determine CL activity of PMDNAzyme [22][23][24]28]. In turn, it does not allow fully using the catalytic potential of PMDNAzyme in analytical practice, where it is desirable to have a catalyst with the maximum possible activity.…”

Chemiluminescence and electrochemiluminescence applications of metal nanoclusters

“…In addition to the ECL in visible region, the near-infrared ECL of metal nanoclusters was also obtained. Ding's group reported the near-infrared ECL of Au 25 (SC 2 H 4 Ph) 18 + -C 6 F 5 CO 2 − (Au 25 + ) (SC 2 H 4 Ph=2-phenylethanethiol) [65], Au 25 (SC 2 H 4 Ph) 18 − (Au 25 − ) [66], Au 144 (SC 2 H 4 Ph) 60 [67], Au 38 (SC 2 H 4 Ph) 24 [68], Au 25 (SC 2 H 4 Ph) 18 [69], successively.…”

“…It can be defined concisely as chemical reactions that emit light [16]. CL has been widely used as detection method in many fields because of its many advantages: large linear response, fast light emission, high stability of reaction reagents, low consumption of expensive reagents, cheap devices, and no problems about light scattering, source instability, or high background because of no excitation light source needed [17][18][19][20][21][22][23][24][25][26][27]. However, the CL emission of molecular systems is usually weak due to low quantum efficiency.…”

Aptamers and molecularly imprinted polymers as artificial biomimetic receptors in affinity capillary electrophoresis and electrochromatography

“…Detection as low as 0.01% of the minor enantiomer in a nonracemic mixture can be achieved, in a short analysis time (,5 min). Li et al [58] developed an aptamer-based assay to detect the haemin with chemiluminescence (CL) detection [58]. The protein behaved like a direct indicator for the moleculeaptamer interaction; when haemin was bound by aptamers and the complex was separated by CE, a decrease in the CL signal of free haemin occurred.…”