This
work proposed a novel double-engine powered paper photoelectrochemical
(PEC) biosensor based on an anode–cathode cooperative amplification
strategy and various signal enhancement mechanisms, which realized
the monitoring of multiple miRNAs (such as miRNA-141 and miRNA-21).
Specifically, C3N4 quantum dots (QDs) sensitized
ZnO nanostars and BiOI nanospheres simultaneously to construct a composite
photoelectric layer that amplified the original photocurrent of the
photoanode and photocathode, respectively. Through the independent
design and partition of a flexible paper chip to functionalize injection
holes and electrode areas, the bipolar combination completed the secondary
upgrade of signals, which also provided biological reaction sites
for multitarget detection. With the synergistic participation of a
three-dimensional (3D) DNA nanomachine and programmable CRISPR/Cas12a
shearing tool, C3N4 QDs lost their attachment
away from the electrode surface to quench the signal. Moreover, electrode
zoning significantly reduced the spatial cross talk of related substances
for multitarget detection, while the universal trans-cleavage capability
of CRISPR/Cas12a simplified the operation. The designed PEC biosensor
revealed excellent linear ranges for detection of miRNA-141 and miRNA-21,
for which the detection limits were 5.5 and 3.4 fM, respectively.
With prominent selectivity and sensitivity, the platform established
an effective approach for trace multitarget monitoring in clinical
applications, and its numerous pioneering attempts owned favorable
reference values.
The poor stability of cesium lead iodide (CsPbI3) perovskite
nanocrystals (NCs) under light and humidity conditions limits their
practical application. The dynamic binding of ligands is easy to desorb
during the purification process, which results in a deterioration
of their optical performance and stability. In this paper, sodium
dodecyl benzene sulfonate (SDBS) was used to modify the surface of
CsPbI3 NCs. By utilizing the strong combined effect of
benzenesulfonic acid and Pb ions, the poor stability caused by the
loss of weakly interacting amine ligands was effectively improved;
meanwhile, the I ion vacancies can be filled to inhibit the occurrence
of nonradiative recombination, so that the optical performance of
the CsPbI3 NCs is improved. The radiative and nonradiative
recombination process during photoluminescence is deeply discussed.
After modification, the photoluminescence quantum yields of CsPbI3 NCs reached 90.7%, the superior photoluminescence intensity
still retained 83% of the initial intensity after being stored for
60 days under environmental conditions, and the stability in water
was remarkably improved. Additional SDBS was used after purification,
suggesting that the presence of SDBS can effectively improve photostability.
This method offers a new idea for preparing high-performance perovskite-based
devices.
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