2 research outputs found
Quantitative Detection of Potassium Ions and Adenosine Triphosphate via a Nanochannel-Based Electrochemical Platform Coupled with G‑Quadruplex Aptamers
The
development of synthetic nanopores and nanochannels that mimick
ion channels in living organisms for biosensing applications has been,
and still remains, a great challenge. Although the biological applications
of nanopores and nanochannels have achieved considerable development
as a result of nanotechnology advancements, there are few reports
of a facile way to realize those applications. Herein, a nanochannel-based
electrochemical platform was developed for the quantitative detection
of biorelated small molecules such as potassium ions (K<sup>+</sup>) and adenosine triphosphate (ATP) in a facile way. For this purpose,
K<sup>+</sup> or ATP G-quadruplex aptamers were covalently assembled
onto the inner wall of porous anodic alumina (PAA) nanochannels through
a Schiff reaction between −CHO groups in the aptamer and amino
groups on the inner wall of the PAA nanochannels under mild reaction
conditions. Conformational switching of the aptamers confined in the
nanochannels occurs in the presence of the target molecules, resulting
in increased steric hindrance in the nanochannels. Changes in steric
hindrance in the nanochannels were monitored by the anodic current
of indicator molecules transported through the nanochannels. As a
result, quantitative detection of K<sup>+</sup> and ATP was realized
with a concentration ranging from 0.005 to 1.0 mM for K<sup>+</sup> and 0.05 to 10.0 mM for ATP. The proposed platform displayed significant
selectivity, good reproducibility, and universality. Moreover, this
platform showed its potential for use in the detection of other aptamer-based
analytes, which could promote its development for use in biological
detection and clinical diagnosis
Chemically Modulated Carbon Nitride Nanosheets for Highly Selective Electrochemiluminescent Detection of Multiple Metal-ions
Chemical
structures of two-dimensional (2D) nanosheet can effectively
control the properties thus guiding their applications. Herein, we
demonstrate that carbon nitride nanosheets (CNNS) with tunable chemical
structures can be obtained by exfoliating facile accessible bulk carbon
nitride (CN) of different polymerization degree. Interestingly, the
electrochemiluminescence (ECL) properties of as-prepared CNNS were
significantly modulated. As a result, unusual changes for different
CNNS in quenching of ECL because of inner filter effect/electron transfer
and enhancement of ECL owing to catalytic effect were observed by
adding different metal ions. On the basis of this, by using various
CNNS, highly selective ECL sensors for rapid detecting multiple metal-ions
such as Cu<sup>2+</sup>, Ni<sup>2+</sup>, and Cd<sup>2+</sup> were
successfully developed without any labeling and masking reagents.
Multiple competitive mechanisms were further revealed to account for
such enhanced selectivity in the proposed ECL sensors. The strategy
of preparing CNNS with tunable chemical structures that facilely modulated
the optical properties would open a vista to explore 2D carbon-rich
materials for developing a wide range of applications such as sensors
with enhanced performances