166
Jyotsna et al.
4.1 Biological Applications of Fullerenes
Along with their efficient distribution in blood and local organs, these fullerenes
are extensively used in angiography, organ-specific imaging, oxidative stress reduction and gene/drug delivery. Fullerenes functionalized with iodine is a potential
X-ray contrast agent with prolonged retention in the blood. It also provides excellent in vivo biocompatibility compared to other clinically available X-ray agents.
Metallo-fullerenes are advantageous compared to other metal nanoparticles in terms
of toxicity as they release fewer metals/ions due to the stable caging effect provided
by C 60 [47].
4.1.1 Fullerenes in Drug and Gene Delivery
The delivery of drugs/genes directly into the cells is a major challenge due to the three
membrane barriers. Fullerenes are inorganic nanoparticles with a hydrophobic core.
The functional groups attached to the core provide complexity to the behavior of
the fullerene molecule. Attaching hydrophilic moieties makes them water-soluble
and capable of carrying drugs and genes for delivery [48]. DNA functionalized
fullerenes show better efficiency than commercially available lipid-based vectors
in COS-1 cells, increasing the lifetime of DNA in endosomes by supporting their
chromosomal incorporation [49]. The peptide-fullerene conjugate was evaluated for
its ability to penetrate through flexed and unflexed skin. The mechanical flexion
that alters the structural organization of skin increases penetration by conceding
the permeability barrier of the epidermis, which suggests that the fullerenes can also
penetrate through intact skin [50]. The genotoxicity of the fullerenes was determined
in bacterial reverse mutation in hamster lung cells followed by oral administration of
fullerenes to the rats. The fullerenes did not induce toxicity in vitro or in vivo [51].
4.1.2 Fullerenes in the Diagnostic Application
Fullerenes captured with metal ions have potential in the diagnostic application
and are known as endofullerenes or metallofullerenes. These metallofullerenes are
applied as magnetic resonance imaging contrast agent (MRI), X-ray imaging agents
and radiopharmaceuticals. Holmium a metallofullerol molecule, could accumulate
in the liver and can be detected in the bone. This shows that these fullerenes
are targeted to tissues that are rich in macrophages. It could also be useful as a
chemotherapeutic agent for the treatment of leukemia and bone cancer [52]. Another
study revealed that when fullerene derivatives were used for carrying serum protein
profiling, it helped identify proteins for pathologies and biomarker discovery using
the material-enhanced laser desorption (MALDI) technique. Direct laser irradiation
of the adsorbed protein was applied over the range m/z 2000–3000 for screening the
proteins present in serum.
Jyotsna et al.
4.1 Biological Applications of Fullerenes
Along with their efficient distribution in blood and local organs, these fullerenes
are extensively used in angiography, organ-specific imaging, oxidative stress reduction and gene/drug delivery. Fullerenes functionalized with iodine is a potential
X-ray contrast agent with prolonged retention in the blood. It also provides excellent in vivo biocompatibility compared to other clinically available X-ray agents.
Metallo-fullerenes are advantageous compared to other metal nanoparticles in terms
of toxicity as they release fewer metals/ions due to the stable caging effect provided
by C 60 [47].
4.1.1 Fullerenes in Drug and Gene Delivery
The delivery of drugs/genes directly into the cells is a major challenge due to the three
membrane barriers. Fullerenes are inorganic nanoparticles with a hydrophobic core.
The functional groups attached to the core provide complexity to the behavior of
the fullerene molecule. Attaching hydrophilic moieties makes them water-soluble
and capable of carrying drugs and genes for delivery [48]. DNA functionalized
fullerenes show better efficiency than commercially available lipid-based vectors
in COS-1 cells, increasing the lifetime of DNA in endosomes by supporting their
chromosomal incorporation [49]. The peptide-fullerene conjugate was evaluated for
its ability to penetrate through flexed and unflexed skin. The mechanical flexion
that alters the structural organization of skin increases penetration by conceding
the permeability barrier of the epidermis, which suggests that the fullerenes can also
penetrate through intact skin [50]. The genotoxicity of the fullerenes was determined
in bacterial reverse mutation in hamster lung cells followed by oral administration of
fullerenes to the rats. The fullerenes did not induce toxicity in vitro or in vivo [51].
4.1.2 Fullerenes in the Diagnostic Application
Fullerenes captured with metal ions have potential in the diagnostic application
and are known as endofullerenes or metallofullerenes. These metallofullerenes are
applied as magnetic resonance imaging contrast agent (MRI), X-ray imaging agents
and radiopharmaceuticals. Holmium a metallofullerol molecule, could accumulate
in the liver and can be detected in the bone. This shows that these fullerenes
are targeted to tissues that are rich in macrophages. It could also be useful as a
chemotherapeutic agent for the treatment of leukemia and bone cancer [52]. Another
study revealed that when fullerene derivatives were used for carrying serum protein
profiling, it helped identify proteins for pathologies and biomarker discovery using
the material-enhanced laser desorption (MALDI) technique. Direct laser irradiation
of the adsorbed protein was applied over the range m/z 2000–3000 for screening the
proteins present in serum.