activated by the adenosine-aptamer binding event (Fig. 12b). The inherently unstable aptamer-trigger:H1 intermediate catalyzed the dynamic assembly of H1 and H2
to produce H1:H2 duplex, accompanying with the release of aptamer-trigger. The
dissociated aptamer-trigger could further motivate the next CHA reaction and finally
result in the formation of numerous H1:H2 duplex. Due to the steric hindrance effect,
pyrene labeled at the H1:H2 duplex was difficult to enter the cavity of β-CDP, which
led to a decreased fluorescence emission. Under the optimized conditions, a low
detection limit of 42 nM was obtained by the combination of the superior
recognization capability of β-CDP and CHA-induced signal amplification. The
proposed biosensor may extend the aptamer-based sensing application, not just
nucleic acid and protein.
Fig. 12 Schematic illustration of the proposed enzyme-free nucleic acid amplified detection
method based on catalyzed dynamic assembly and host-guest interactions between β-cyclodextrin
polymer and pyrene. Numbers marked with * are complementary to the corresponding unmarked
numbers [75]
246
J. Jiang et al.