b2815 Tissue Engineering and Nanotheranostics “9.61x6.69”
104 Tissue Engineering and Nanotheranostics
particular applications. All man-made and biological systems have
been existing at the nanoscale naturally as nanotubes, nanocrystals
and nanobiomotors. This natural phenomena has already been exist-
ing in the environment and in the living systems, e.g. a DNA mole-
cule is about 2.5 nm wide, while a sodium atom is about 0.2 nm. The
promising features of employing nanoparticles as theranostics are
their ability to localize the site of disease accurately and reduce the
unwanted side effects. Combining imaging, diagnostic and therapeu-
tic functions in single modality or particle has significant influence in
biomedical applications.^11
The dimensions of these nanometric materials prevent them from
readily paring through the kidneys. Therefore, circulation in the
blood pool is longer, depending on their surface functionalization
qualities. Moreover, the novel properties of theranostics nanomateri-
als observed are attributed to their: (1) shape (spherical versus tube)
and morphological structure illustrated by size-induced effects (nar-
row size distribution, large surface area); (2) chemical composition
(high purity and good crystallinity, etc.); (3) solubility in different
media; and (4) surface structure (inorganic or organic surface coat-
ings and increased surface reactivity). The above-mentioned proper-
ties of nanoparticles are very significant in bionanotechnology. For
example, in cancer treatments, if the tumor is of many types, then
blood vessels are irregular in shape, dilated, permeable, and can be
create fenestrations in endothelial cells. Nanoparticles can easily pen-
etrate into tumor tissues and can be preserved because of weak lym-
phatic drainage. Thus, the permeability and retention (EPR) effect
enhances due to the selective accretion of nanosized particles near
tumor tissues.12–14 In addition, nanoscale particles have high surface
area to volume ratios, and the ability of acquiescing high loading
capacities. Thus, imaging agents and therapeutic drugs can easily be
loaded on nanoparticles because of their surface chemistry.
Nanoparticles provide access to the various functional groups on their
surface to cloaking agents and targeting ligands which improve the
imaging quality, therapeutic function and reduce systemic toxicity. It
is noteworthy that nanoparticles with their quantum confinement
effects, and small size with large surface area shows unique size-dependent
magnetic, optical, and electronic properties.15–17
