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Self-Sensing Enzyme-Powered Micromotors Equipped with pH-Responsive DNA Nanoswitches
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posted on 2019-02-01, 00:00 authored by Tania Patino, Alessandro Porchetta, Anita Jannasch, Anna Lladó, Tom Stumpp, Erik Schäffer, Francesco Ricci, Samuel SánchezBiocatalytic
micro- and nanomotors have emerged as a new class
of active matter self-propelled through enzymatic reactions. The incorporation
of functional nanotools could enable the rational design of multifunctional
micromotors for simultaneous real-time monitoring of their environment
and activity. Herein, we report the combination of DNA nanotechnology
and urease-powered micromotors as multifunctional tools able to swim,
simultaneously sense the pH of their surrounding environment, and
monitor their intrinsic activity. With this purpose, a FRET-labeled
triplex DNA nanoswitch for pH sensing was immobilized onto the surface
of mesoporous silica-based micromotors. During self-propulsion, urea
decomposition and the subsequent release of ammonia led to a fast
pH increase, which was detected by real-time monitoring of the FRET
efficiency through confocal laser scanning microscopy at different
time points (i.e., 30 s, 2 and 10 min). Furthermore, the analysis
of speed, enzymatic activity, and propulsive force displayed a similar
exponential decay, matching the trend observed for the FRET efficiency.
These results illustrate the potential of using specific DNA nanoswitches
not only for sensing the micromotors’ surrounding microenvironment
but also as an indicator of the micromotor activity status, which
may aid to the understanding of their performance in different media
and in different applications.