quench their fluorescence. Compared to the probes, aconitine had a stronger affinity
with SCX8 and replaced the probes from the SCX8 cavity to achieve fluorescence
“turn-on.” The sensor consisting of SCX8-RGO and three probes were able to detect
aconitine with linear ranges of 1.0–14.0 μM, 2.0–16.0 μM, and 1.0–16.0 μM,
respectively. And detection limits of aconitine were 0.28 μM, 0.60 μM, and
0.37 μM, respectively. Moreover, the sensing system was successfully applied to
the detection of aconitine in human serum.
The IDA strategy was widely used in sensing systems like those discussed above
generally based on lock-and-key model. Unlike IDA strategies but using some of the
ideas of IDA, differential sensing was proposed to address those less selective
receptors in array sensing [32]. The idea of differential sensing was to mimic the
nose of the mammal, using a range of low-selectivity receptors to provide a signal
array for each analyte. The signals for each analyte formed a corresponding fingerprint, thereby enabling classification of the analytes. Hof and co-workers developed
antibody-free detection histone code using calixarene-based chemical sensor arrays
[29]. The posttranslational modification of histones begins with its N-terminal tail,
which includes methylation, quaternization, acetylation, and phosphorylation. These
affect the function of histones in gene regulation and are associated with various
human diseases. Sensing arrays composed of sulfonated calixarenes and dyes were
capable of generating signals for cationic amino acids and peptides, making
corresponding fingerprints for differentiation (Fig. 7). For example, this sensor kit
can identify either methylation and the number of methyl groups on a single histone
tail sequence. In addition, the sensor array can also be used to simultaneously detect
the concentration of histone modifications.
Many of IDA strategies are applied to the detection of biomolecules in water or
biological fluids, but the robustness of these methods is inevitably reduced when
there is a large amount of component interference, such as inorganic salts. Hof and
co-workers reported a self-assembled sensor, DimerDye, that uses a photochemical
guest-sensing mechanism and that is intrinsically tolerant of a competitive biological
environment (Fig. 8) [30]. Modifying the dye directly on the calixarene, two
calixarenes self-assembled into non-emissive dimers through the host-guest interaction in water. When the analyte was detected, the analyte caused the dimer to
dissociate while the fluorescence was restored, allowing fluorescence to be turned
Fig. 6 IDA for aconitine (ACO) using SCX8-RGO [28]. (Reproduced from Ref. [28] with
permission from Elsevier)
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J. Gao and D.-S. Guo
with SCX8 and replaced the probes from the SCX8 cavity to achieve fluorescence
“turn-on.” The sensor consisting of SCX8-RGO and three probes were able to detect
aconitine with linear ranges of 1.0–14.0 μM, 2.0–16.0 μM, and 1.0–16.0 μM,
respectively. And detection limits of aconitine were 0.28 μM, 0.60 μM, and
0.37 μM, respectively. Moreover, the sensing system was successfully applied to
the detection of aconitine in human serum.
The IDA strategy was widely used in sensing systems like those discussed above
generally based on lock-and-key model. Unlike IDA strategies but using some of the
ideas of IDA, differential sensing was proposed to address those less selective
receptors in array sensing [32]. The idea of differential sensing was to mimic the
nose of the mammal, using a range of low-selectivity receptors to provide a signal
array for each analyte. The signals for each analyte formed a corresponding fingerprint, thereby enabling classification of the analytes. Hof and co-workers developed
antibody-free detection histone code using calixarene-based chemical sensor arrays
[29]. The posttranslational modification of histones begins with its N-terminal tail,
which includes methylation, quaternization, acetylation, and phosphorylation. These
affect the function of histones in gene regulation and are associated with various
human diseases. Sensing arrays composed of sulfonated calixarenes and dyes were
capable of generating signals for cationic amino acids and peptides, making
corresponding fingerprints for differentiation (Fig. 7). For example, this sensor kit
can identify either methylation and the number of methyl groups on a single histone
tail sequence. In addition, the sensor array can also be used to simultaneously detect
the concentration of histone modifications.
Many of IDA strategies are applied to the detection of biomolecules in water or
biological fluids, but the robustness of these methods is inevitably reduced when
there is a large amount of component interference, such as inorganic salts. Hof and
co-workers reported a self-assembled sensor, DimerDye, that uses a photochemical
guest-sensing mechanism and that is intrinsically tolerant of a competitive biological
environment (Fig. 8) [30]. Modifying the dye directly on the calixarene, two
calixarenes self-assembled into non-emissive dimers through the host-guest interaction in water. When the analyte was detected, the analyte caused the dimer to
dissociate while the fluorescence was restored, allowing fluorescence to be turned
Fig. 6 IDA for aconitine (ACO) using SCX8-RGO [28]. (Reproduced from Ref. [28] with
permission from Elsevier)
210
J. Gao and D.-S. Guo