Although separation of single-walled carbon nanotubes (SWCNTs) according to their helicity and handedness has been attracting tremendous interest recently, exploration of the left-and right-handed SWCNT enantiomers (defined as "M" and "P") to chiral sensing still remains in the early stage. Here we presented a new electrochemical sensor for chiral discrimination, which for the first time amplified the chiral selection on the electrode surface based on the left-or right-handed semiconducting SWCNT enantiomers with (6,5)-enriched chirality. The enantioselectivity was demonstrated by different peak current response to analyte enantiomers, observed in differential pulse voltammogram (DPV). Chiral distinguishing might be a result of the formation of an efficient chiral nanospace originating from the high purity of single enantiomer of (6,5) SWCNT. The obtained chiral electrodes were also applied to determine the enantiomeric excess (ee) of DOPA. There was a good linear relationship between DPV peak currents and % ee of L-DOPA. This study is the first example showing how the structure of chiral SWCNTs influences electrochemical chiral recognition.
Metal−organic frameworks (MOFs) have been attracting a great attention for application in electrolytes. Benefiting from the controllable chemical composition, tunable pore structure and surface functionality, MOFs offer great opportunities for...
Stereoselective
recognition of amino acids is extremely important
due to its high chirality-dependent interactions and physiological
activities in life activities. We herein report a novel functionalized
chiral fluorescent nanosensor prepared from surface modification of
CdSe/ZnS quantum dots (QDs) with pyroglutamic acid derivatives, which
could serve as a chiral recognition module for fluorescence detection
of chiral molecules. The sensor exhibited a unique stereoselective
fluorescence response to histidine (His), glutamate (Glu), and dihydroxyphenylalanine
(Dopa) and had preferable response performance to l-enantiomers.
The enantiomeric fluorescence difference ratios of His, Glu, and Dopa
enantiomers were 3.90, 3.40, and 2.49, respectively. The mechanism
for the enantiomeric fluorescence recognition was systematically studied
through a fluorescence spectrum, fluorescence life, and density functional
theory (DFT) calculation. Presumably, the different hydrogen bonding
capacity of the chiral recognition module with two enantiomers mainly
contributed to the difference in fluorescence signals. As a result,
a broader application of the pyroglutamic acid derivative-coated QDs
as a fluorescence-responsive chiral sensing platform for enantiomeric
detection would be expected.
In response to the urgency of reducing CO2 emissions, nearly 200 countries have joined the "Paris Agreement". It sets long-term low-carbon development goals, which aim to achieve carbon neutrality in...
Real-time in situ monitoring of miRNAs in living
cells is often appealed to signal amplifiers to tackle their low abundance
challenges. However, the poor kinetics of amplifiers and potential
interferences from the complex intracellular environment hamper its
widespread applications in vivo. Herein, we report
a framework nucleic acid (FNA)-based nonenzymatic spatial-confinement
amplifier for rapid and reliable intracellular miRNA imaging. The
amplifier consists of a localized catalytic hairpin assembly (L-CHA)
reactor encapsulated in the inner cavity of an FNA (a 20 bp cube).
The L-CHA reactor is certainly confined to the internal frame by integrating
two probes (H1 and H2) of the L-CHA within a DNA strand and harnessing
it to the opposite angles of the cube. We find that the stability
of the amplifier is remarkably improved due to the protection of the
FNA. More importantly, the spatial-confinement effect of the FNA can
endow the confined L-CHA amplifier with enhanced local concentrations
of reagents (5000-fold), thereby accelerating the reaction rate and
improving the dynamic performance (up to 14.34-fold). With these advantages,
the proposed amplifier can enable accurate and effective monitoring
of miRNA expression levels in living cells and poses great potential
in medical diagnostics and biomedical research.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.