Biomedical Applications of Carbon-Based Nanomaterials
163
the immobilization of biomolecules, their target recognition and the transduction
process, they are classified into two categories viz., electrochemical and optical-based
biosensors [31]. Different classes of CNT-based biosensors conjugated with DNA,
antibodies, peptides, or enzymes have been developed to detect cancer biomarkers.
CNT based optical biosensors have been developed to detect HIV in complex media,
and an improved emission of response was detected in the presence of serum. The
introduction of target microRNA-19 DNA and non-complementary control resulted
in the analysis of the emission ability of biosensors. The electrical-based CNTbiosensors vertically functionalized with an amine group and conjugated with folic
acid (FA-VCNT (Folic acid vertically aligned Carbon nanotubes)) were studied to
detect cancer cells in normal MRC-5 and QUDM cancer cell lines isolated from
lungs. The number of cancer cells entrapped on FA-VCNT improved as compared
to Vertically aligned carbon nanotubes (VACNTs) [32]. Modifications in the structure, electrical conductivity, and other properties of the CNTs have been exploited
in recent years. Electrochemically modified bioconjugated CNTs have shown potential for detecting molecular markers or immune sensors such as a carcinoembryonic
antigen, interleukins for the early detection of cancers [33].
Enzyme biosensors, the tyrosinase biosensor, is widely used for the estimation of
glucose level [34]. The reason behind this is the biomolecular conjugation is the electrocatalytic activity, greater surface area of MWCNTs. These CNTs, as biosensors,
are involved in several fields like medical and forensic diagnosis. DNA is adsorbed
on the CNTs and these CNT-DNA complexes are highly suitable in biosensing of
several properties of the bioactive species. A cyclodextrin-CNT composite-based
biosensor has been developed recently to detect cholesterol in rhodamine presence
[35].
3.2 CNTs in Therapy
CNTs have the potential applications towards cancer bioimaging and gene and drug
delivery. They can be used for therapeutic applications via two categories: (1) via
oxidative stress and photothermal effect and (2) via drug and gene delivery. Anticancer drugs such as methotrexate, paclitaxel, and cisplatin can be conjugated to
CNT in a high drug to CNT ratios. These bioconjugated CNTs can be delivered in
specific cells by targeting the cancer molecules. Si-RNA can be delivered intracellularly using CNT and it can suppress the growth of tumour by activating the necrosis
or inhibiting the hypoxia-inducible factors [36].
3.2.1 Cancer Therapy
Cancer is the uncontrolled proliferation of cells. CNTs have been used for cancer
treatment due to their nanometric size, high drug loading efficiency and high surface
functionality for the conjugation of bioactive molecules. It has been reported that
163
the immobilization of biomolecules, their target recognition and the transduction
process, they are classified into two categories viz., electrochemical and optical-based
biosensors [31]. Different classes of CNT-based biosensors conjugated with DNA,
antibodies, peptides, or enzymes have been developed to detect cancer biomarkers.
CNT based optical biosensors have been developed to detect HIV in complex media,
and an improved emission of response was detected in the presence of serum. The
introduction of target microRNA-19 DNA and non-complementary control resulted
in the analysis of the emission ability of biosensors. The electrical-based CNTbiosensors vertically functionalized with an amine group and conjugated with folic
acid (FA-VCNT (Folic acid vertically aligned Carbon nanotubes)) were studied to
detect cancer cells in normal MRC-5 and QUDM cancer cell lines isolated from
lungs. The number of cancer cells entrapped on FA-VCNT improved as compared
to Vertically aligned carbon nanotubes (VACNTs) [32]. Modifications in the structure, electrical conductivity, and other properties of the CNTs have been exploited
in recent years. Electrochemically modified bioconjugated CNTs have shown potential for detecting molecular markers or immune sensors such as a carcinoembryonic
antigen, interleukins for the early detection of cancers [33].
Enzyme biosensors, the tyrosinase biosensor, is widely used for the estimation of
glucose level [34]. The reason behind this is the biomolecular conjugation is the electrocatalytic activity, greater surface area of MWCNTs. These CNTs, as biosensors,
are involved in several fields like medical and forensic diagnosis. DNA is adsorbed
on the CNTs and these CNT-DNA complexes are highly suitable in biosensing of
several properties of the bioactive species. A cyclodextrin-CNT composite-based
biosensor has been developed recently to detect cholesterol in rhodamine presence
[35].
3.2 CNTs in Therapy
CNTs have the potential applications towards cancer bioimaging and gene and drug
delivery. They can be used for therapeutic applications via two categories: (1) via
oxidative stress and photothermal effect and (2) via drug and gene delivery. Anticancer drugs such as methotrexate, paclitaxel, and cisplatin can be conjugated to
CNT in a high drug to CNT ratios. These bioconjugated CNTs can be delivered in
specific cells by targeting the cancer molecules. Si-RNA can be delivered intracellularly using CNT and it can suppress the growth of tumour by activating the necrosis
or inhibiting the hypoxia-inducible factors [36].
3.2.1 Cancer Therapy
Cancer is the uncontrolled proliferation of cells. CNTs have been used for cancer
treatment due to their nanometric size, high drug loading efficiency and high surface
functionality for the conjugation of bioactive molecules. It has been reported that