Selection and Characterization of PCB-Binding DNA Aptamers

Abstract

Polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) that resist natural degradation and bioaccumulate in nature. Combined with their toxicity, this leads them to cause cancer and other health hazards. Thus, there is a vital need for rapid and sensitive methods to detect PCB residues in food and in the environment. In this study, PCB-binding DNA aptamers were developed using PCB72 and PCB106 as targets for aptamer selection. Aptamers are synthetic DNA recognition elements which form unique conformations that enable them to bind specifically to their targets. Using in vitro selection techniques and fluorometry, an aptamer that binds with nanomolar affinity to both the PCBs has been developed. It displayed high selectivity to the original target congeners and limited affinity toward other PCB congeners (105, 118, 153, and 169), suggesting general specificity for the basic PCB skeleton with varying affinities for different congeners. This aptamer provides a basis for constructing an affordable, sensitive, and high-throughput assay for the detection of PCBs in food and environmental samples and offers a promising alternative to existing methods of PCB quantitation. This study therefore advances aptamer technology by targeting one of the highly sought-after POPs, for the first time ever recorded.

In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element against Atrazine

“…The data is presented relative to R12.23 binding to atrazine as has been previously described [37,38,39]. Analysis showed significantly higher binding of R12.23 to atrazine in solution than to four of the five negative targets used in the selection ( p < 0.05) (Table 3).…”

“…Each set of specific binding studies were performed in triplicate. Data were averaged and standard deviations calculated, with values presented relative to average atrazine binding as previously described [37,38,39]. For each eluent, a student's t-test was performed to determine statistical differences in the means.…”

Recent trends in SELEX technique and its application to food safety monitoring

“…The detailed basic steps of SELEX process are presented in Fig. 1 [19]. Specifically, SELEX process includes (1) the incubation of target molecules with the random sequence pools, (2) and the subsequent separation of unbound oligonucleotides and the elution of bound oligonucleotides, (3) then PCR amplification of bound aptamers.…”

A “signal-on’’ aptasensor for simultaneous detection of chloramphenicol and polychlorinated biphenyls using multi-metal ions encoded nanospherical brushes as tracers

“…It can be accumulated by millions of times in fish and mammals, which can induce serious neuroreproductive toxicity, immunotoxicity, and tumor promotion to human health Xu et al, 2012;Ottonello et al, 2014). Therefore, the two bio-accumulative compounds residues have designated tolerance levels for CAP of 0.3 μg kg À 1 and PCBs that range between 0.2 and 3 μg kg À 1 in food, and these residue limits are used to determine whether or not a food is safe to consume (Bangemann, 1994;Mehta et al, 2012). Thus, in the study, CAP, PCB72 were used as a model for detection in fish samples.…”