Aptazyme–Gold Nanoparticle Sensor for Amplified
Molecular Probing in Living Cells
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Abstract
To
date, a few of DNAzyme-based sensors have been successfully
developed in living cells; however, the intracellular aptazyme sensor
has remained underdeveloped. Here, the first aptazyme sensor for amplified
molecular probing in living cells is developed. A gold nanoparticle
(AuNP) is modified with substrate strands hybridized to aptazyme strands.
Only the target molecule can activate the aptazyme and then cleave
and release the fluorophore-labeled substrate strands from the AuNP,
resulting in fluorescence enhancement. The process is repeated so
that each copy of target can cleave multiplex fluorophore-labeled
substrate strands, amplifying the fluorescence signal. Results show
that the detection limit is about 200 nM, which is 2 or 3 orders of
magnitude lower than that of the reported aptamer-based adenosine
triphosphate (ATP) sensors used in living cells. Furthermore, it is
demonstrated that the aptazyme sensor can readily enter living cells
and realize intracellular target detection