Biomedical Engineering Reference
In-Depth Information
the chemical design as applied to optical, magnetic resonance, computer
tomography, radionuclide, and multi-modality imaging have been reported
by Longmire
et al.
[70]. Ligand exchanged gold quantum dots (GQDs)
conjugated with cell-penetrating peptides are a new class of photolumi-
nescent probes for nuclear targeting and intracellular imaging [71]. h e
potential applications of biochips, nanosensors, bioreactors, neural stem
cells, immune nanoparticles, biodegradable polymers, and convection-
enhanced drug delivery in the diagnosis and treatment of diseases are hot
topics in the future of nanomedicine. Numerous novel medicinal forms
are polymeric nanoparticles, nanotubes, micelles, liposomes, dendrimers,
fullerenes, and hydrogels [72]. Most ocular diseases are treated by topical
drug application in the form of solutions, suspensions and ointments. h ese
conventional dosage forms suf er from the problems of poor ocular bio-
availability, because of various anatomical and pathophysiological barriers
prevailing in the eye. Applications of various nanoparticulate systems like
microemulsions, nanosuspensions, nanoparticles, liposomes, niosomes,
dendrimers and cyclodextrins in the i eld of ocular drug delivery can be
utilized to explore the frontiers of ocular drug delivery and therapy [73].
Generation 4 PAMAM-NH
2
(G4NH
2
) dendrimer labeled with tritium to
measure the rate of uptake and permeability in Caco-2 cells was established
by Kichens
et al.
using endocytosis inhibitors brefeldin A, colchicine, i li-
pin, and sucrose, and suggested that G4NH
2
internalization and transport
involves an endocytosis pathway [74]. Dendrimers with precise control of
size, shape and terminal group functionality have been established for a
wide range of pharmaceutical applications [75]. h ere is growing inter-
est in developing tissue-specii c multifunctional drug delivery systems
with the ability to diagnose or treat several diseases. Nanosized Au metal-
dendrimer composite nanodevices (CNDs) consist of poly(amidoamine)
dendrimers (in various sizes, surface substituents, and net charges) and
inorganic nanoparticles, properties of both of which can be individually
modii ed and optimized in mouse tumor models [76]. Mesoporous silica
nanomaterials for controlled drug release, gene and neurotransmitter
delivery applications have been established. h e high surface area, tunable
pore diameter (2-20 nm) and uniform mesoporous structure (hexagonal
channels or cubic pores) of the mesoporous silicas of er a unique advan-
tage for loading and releasing large quantities of biomedical agents. h e
strategy of using various removable capping moieties, such as photo- or
redox-responsive organic groups, inorganic nanoparticles, dendrimers
and polymers, to encapsulate guest biomolecules inside the porous matri-
ces further enables the utilization of these surface-functionalized mesopo-
rous silica nanomaterials for stimuli-responsive controlled release
in vitro
