Biomedical Applications of Carbon-Based Nanomaterials
161
due to the larger size and excretion through glomerular filtration. Hence, to enhance
the delivery of DNA and si-RNA into the cells, Plasmid DNA, along with NDs,
were used to enhance the delivery properties via electrostatic forces. Similarly, antigreen fluorescent protein si-RNA was delivered to breast cancer cells using NDs and
plasmid-based complex ND-PEI800 [25, 26].
2.3 Use as Bio-imaging Agents
Nds are emerging as efficient and safe candidates for cellular imaging due to their
bright fluorescence, high photostability with a sufficiently long lifetime, and excellent
biocompatibility. Nds were conjugated with transferrin through an amide linkage to
form ND-transferrin conjugates. These conjugates were incubated with HeLa cells.
The expression of transferrin was detected using a 514.5 nm laser source, and confocal
fluorescence images were obtained to determine the uptake mechanism of transferrin
in HeLa cells [27]. The uptake and interaction of NDs with cancer and non-cancer
cells were analyzed via fluorescence imaging. The mechanism of NDs uptake by cells
was analyzed by blocking the endocytosis pathways, mainly the clathrin-dependent
pathways. It was observed that the cancer cells had significantly more amount of
NDs than non-cancer cells.
3 Carbon Nanotubes (CNTs)
Carbon nanotubes consist of a rolled-up graphene sheet having a diameter of about
100 nm (Fig. 3). These carbon nanotubes (CNTs) are used in the nanomedicine
and bioimaging areas due to their broad absorption spectra in UV-vis-NIR regions,
large surface areas, and Raman bands. The Raman scattering features of the CNTs
allow the evaluation of the signal intensities produced during the binding and
conjugation of biomolecules to the CNT. This method allows the microarray-based
biosensing of biomolecules with high sensitivity [28]. Functionalization of CNTs
by hydrophilic molecules and reactive functional groups makes them suitable for
biosensing, bioimaging, drug and gene delivery, and phototherapy. Chemical modifications of the CNTs allow the addition of various functional groups, probes,
biomolecules, and antibodies to their surface [29]. Figure 4 shows the schematic
of synthesis, characterization, and purification of CNTs.
3.1 CNTs as Biosensors
Properties like high conductivity, chemical stability and fast electron transfer rate
make these CNTs an appropriate tool for biosensing applications [30]. Based on
161
due to the larger size and excretion through glomerular filtration. Hence, to enhance
the delivery of DNA and si-RNA into the cells, Plasmid DNA, along with NDs,
were used to enhance the delivery properties via electrostatic forces. Similarly, antigreen fluorescent protein si-RNA was delivered to breast cancer cells using NDs and
plasmid-based complex ND-PEI800 [25, 26].
2.3 Use as Bio-imaging Agents
Nds are emerging as efficient and safe candidates for cellular imaging due to their
bright fluorescence, high photostability with a sufficiently long lifetime, and excellent
biocompatibility. Nds were conjugated with transferrin through an amide linkage to
form ND-transferrin conjugates. These conjugates were incubated with HeLa cells.
The expression of transferrin was detected using a 514.5 nm laser source, and confocal
fluorescence images were obtained to determine the uptake mechanism of transferrin
in HeLa cells [27]. The uptake and interaction of NDs with cancer and non-cancer
cells were analyzed via fluorescence imaging. The mechanism of NDs uptake by cells
was analyzed by blocking the endocytosis pathways, mainly the clathrin-dependent
pathways. It was observed that the cancer cells had significantly more amount of
NDs than non-cancer cells.
3 Carbon Nanotubes (CNTs)
Carbon nanotubes consist of a rolled-up graphene sheet having a diameter of about
100 nm (Fig. 3). These carbon nanotubes (CNTs) are used in the nanomedicine
and bioimaging areas due to their broad absorption spectra in UV-vis-NIR regions,
large surface areas, and Raman bands. The Raman scattering features of the CNTs
allow the evaluation of the signal intensities produced during the binding and
conjugation of biomolecules to the CNT. This method allows the microarray-based
biosensing of biomolecules with high sensitivity [28]. Functionalization of CNTs
by hydrophilic molecules and reactive functional groups makes them suitable for
biosensing, bioimaging, drug and gene delivery, and phototherapy. Chemical modifications of the CNTs allow the addition of various functional groups, probes,
biomolecules, and antibodies to their surface [29]. Figure 4 shows the schematic
of synthesis, characterization, and purification of CNTs.
3.1 CNTs as Biosensors
Properties like high conductivity, chemical stability and fast electron transfer rate
make these CNTs an appropriate tool for biosensing applications [30]. Based on