Topics in Current Chemistry (2020) 378:15
1 3
upon recognition of a target, so, numerous applications are reporting the design of
nanotube-based biosensors to detect and monitor different pathologies [136, 137].
Recently, a three-dimensional network of carbon nanotubes on Si pillar substrate has
been developed for the accurate detection of oral squamous cell carcinoma in clinical saliva samples [138]. In this work, Song and colleagues described the preparation of the sensor, the in vitro characterization, and the clinical applicability. The
results obtained with this new CNT network showed a good correlation with data
obtained using the commercially available electrochemiluminescence detection system employed in the hospital. Also, a novel CNT-based biosensor has been used
for ultrasensitive detection of hydrogen peroxide and glucose in human serum, with
a great interest for basic research and disease diagnosis [139]. In this study, the
authors constructed a ratiometric fluorescent nanosensor based on the peroxidaselike properties of a hierarchical cobalt/carbon nanotube hybrid nanocomplex. This
system assay developed reaches a detection limit of H 2 O 2 of 100 nM and a selective and sensitive detection of glucose as low as 150 nM. In a different approach,
multivalent electrodes for glucose biosensing were constructed through multiple
functionalization of CNTs [140]. Three different pyrene derivatives were simultaneously immobilized on the nanotube surface by π–π-stacking: adamantane-pyrene,
biotinpyrene, and nitrilotriacetic. They were adsorbed on the nanotube sidewalls to
allow the step-by-step immobilization, via supramolecular host–guest interactions,
of β-cyclodextrin modified glucose oxidase, biotinylated glucose oxidase, and histidine modified glucose (Fig. 8). The calibration curves for the glucose responses
were performed by amperometry and using glucose oxidase as an enzyme model for
all immobilization steps.
DNA detection is a very active research area holding great promise in the early
detection of many diseases and pathological processes, and CNTs offer strong
opportunities to achieve that [141]. An interesting study reported the synthesis of
a multi-functional gold/iron-oxide nanoparticle-CNT as a virus DNA-sensing platform [142]. The authors prepared the sensor through a simple two-step method
obtaining the hybrid nanostructure that exhibited excellent detection potential and
DNA sensing performance for different diseases. Chen and collogues also reported
the fabrication of a DNA nano-biosensor system containing carbon nanotubes to
detect the presence of Mycobacterium tuberculosis rapidly and with a great sensitivity [143]. CNTs have also been experimentally and theoretically investigated as
conducting channels in a chemiresistor for the electrochemical detection of doublestranded DNA [144]. More recently, the development of a CNT-based field-effect
transistor for DNA hybridization detection was reported [145]. In this sensor, DNA
can bind well to a suspended CNT, avoiding the adverse effects of a substrate on a
sensing material, and reaching a detection limit up to 10 aM.
4.1.2 Imaging
Carbon nanotubes can be powerful tools with diagnosis purposes not only as biosensors but also to be used in imaging technologies. Due to their excellent intrinsic
properties, CNTs have been employed as CAs in photoimaging techniques and are
good platforms to carry molecules that make them detectable with different imaging
194
Reprinted from the journal
1 3
upon recognition of a target, so, numerous applications are reporting the design of
nanotube-based biosensors to detect and monitor different pathologies [136, 137].
Recently, a three-dimensional network of carbon nanotubes on Si pillar substrate has
been developed for the accurate detection of oral squamous cell carcinoma in clinical saliva samples [138]. In this work, Song and colleagues described the preparation of the sensor, the in vitro characterization, and the clinical applicability. The
results obtained with this new CNT network showed a good correlation with data
obtained using the commercially available electrochemiluminescence detection system employed in the hospital. Also, a novel CNT-based biosensor has been used
for ultrasensitive detection of hydrogen peroxide and glucose in human serum, with
a great interest for basic research and disease diagnosis [139]. In this study, the
authors constructed a ratiometric fluorescent nanosensor based on the peroxidaselike properties of a hierarchical cobalt/carbon nanotube hybrid nanocomplex. This
system assay developed reaches a detection limit of H 2 O 2 of 100 nM and a selective and sensitive detection of glucose as low as 150 nM. In a different approach,
multivalent electrodes for glucose biosensing were constructed through multiple
functionalization of CNTs [140]. Three different pyrene derivatives were simultaneously immobilized on the nanotube surface by π–π-stacking: adamantane-pyrene,
biotinpyrene, and nitrilotriacetic. They were adsorbed on the nanotube sidewalls to
allow the step-by-step immobilization, via supramolecular host–guest interactions,
of β-cyclodextrin modified glucose oxidase, biotinylated glucose oxidase, and histidine modified glucose (Fig. 8). The calibration curves for the glucose responses
were performed by amperometry and using glucose oxidase as an enzyme model for
all immobilization steps.
DNA detection is a very active research area holding great promise in the early
detection of many diseases and pathological processes, and CNTs offer strong
opportunities to achieve that [141]. An interesting study reported the synthesis of
a multi-functional gold/iron-oxide nanoparticle-CNT as a virus DNA-sensing platform [142]. The authors prepared the sensor through a simple two-step method
obtaining the hybrid nanostructure that exhibited excellent detection potential and
DNA sensing performance for different diseases. Chen and collogues also reported
the fabrication of a DNA nano-biosensor system containing carbon nanotubes to
detect the presence of Mycobacterium tuberculosis rapidly and with a great sensitivity [143]. CNTs have also been experimentally and theoretically investigated as
conducting channels in a chemiresistor for the electrochemical detection of doublestranded DNA [144]. More recently, the development of a CNT-based field-effect
transistor for DNA hybridization detection was reported [145]. In this sensor, DNA
can bind well to a suspended CNT, avoiding the adverse effects of a substrate on a
sensing material, and reaching a detection limit up to 10 aM.
4.1.2 Imaging
Carbon nanotubes can be powerful tools with diagnosis purposes not only as biosensors but also to be used in imaging technologies. Due to their excellent intrinsic
properties, CNTs have been employed as CAs in photoimaging techniques and are
good platforms to carry molecules that make them detectable with different imaging
194
Reprinted from the journal