Cortisol is a stress hormone and the abnormal secretion of cortisol is related to many chronical diseases and neurological disorders. To detect cortisol, two DNA aptamers have been reported so...
Estrogenic compounds such as estrone (E1), 17β-estradiol
(E2), and 17α-ethynylestradiol (EE2) are serious environmental
contaminants due to their potent biological activities. At least six
selections were previously reported to obtain DNA aptamers for E2,
highlighting its environmental importance. A careful analysis revealed
that the previous aptamers either are too long or do not bind optimally.
Herein, a series of new aptamers were obtained from the capture-SELEX
method with dissociation constants down to 30 nM as determined by
isothermal titration calorimetry (ITC). Two aptamers were converted
to structure-switching fluorescent biosensors, which achieved a limit
of detection down to 3.3 and 9.1 nM E2, respectively. One aptamer
showed similar binding affinities to all the three estrogens, while
the other aptamer is more selective for E2. Both aptamers required
Mg2+ for binding. The proposed sensors were successfully
applied in the determination of E2 in wastewater. Moreover, comparisons
were made with previous aptamers based on primary sequence alignment
and secondary structures. Among previously reported truncated aptamers,
ITC showed binding only in one of them. The newly selected aptamers
have the combined advantages of small size and high affinities.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.