Biomedical Engineering Reference
In-Depth Information
11.3 NANOTECHNOLOGY IN THE ARENA OF PULMONARY THERAPY
Nanotechnology holds an enormous promise for improving the health as well as eminence of life
in people throughout the world. The beneficial effects of nanotechnology in numerous medical
applications seem extremely promising. In recent years, there is noteworthy attention in developing
biodegradable nanoparticles (NPs) as drug-and-gene delivery systems [28,29]. Basically, the term
“nanotechnology” refers to the exploitation of materials at the nanometric scale, that is, to a bil-
lionth part of a meter. It deals specifically with the design, characterization, and production of novel
nanostructures, nanodevices, and nanosystems, with controlled shapes, sizes, forms, and properties
of matter at aforementioned stated scales for varying purposes. These colloidal particles are usually
formulated using biodegradable polymers in which a therapeutic agent can be entrapped, adsorbed,
or chemically coupled. There are considerable advantages with using NPs as drug delivery carriers,
which chiefly include [30]
•
A small size [31]
•
The propensity to penetrate through smaller capillaries/pores
•
Efficiencies in the resulting drug accumulation at the site of action [32]
•
Allowing for a sustained drug release over a period of days or even weeks [33,34]
•
Modifiable surfaces: surfaces can be modified to be conjugated to drugs, proteins, or
peptides
•
They can be modified by ligands, probes, or proteins to alter the biodistribution of drugs
and to achieve target-specific drug delivery [35,36] U.S.F.D.A.-approved polymers are
available for human use [37]
In 2004, the nanotechnology market was valued at approximately $13 billion, which increased to
nearly $50 billion by 2006. Estimates for product sales in 2008 fix that value between $100 and $150
billon, with market expectations for 2010 set at $500 billion, and between $1 and $2 trillion by 2015.
This “nano boom” clearly reflects the expected technological construction of a defined architecture
that bears ample associated applications [38]. Engineered nanomaterials such as the quantum dots,
dendrimers, carbon nanotubes (CNTs), and fullerenes exemplify nanomaterials that have diameters
less than 100 nm and can be compared with the sizes of several living structures (Figure 11.1).
Nanotech industries are reaching new horizons with the progression of these innovative classes of
nanomaterials, extending applications to advance the excellence of healthcare commodities with
superior patient compliance (Figure 11.2).
11.4 VARIOUS NANOMATERIALS USED IN PULMONARY DELIVERY:
TOXICITY CONCERNS
Nanoparticulate entities can enter living organisms through ingestion (oral route), dermal absorp-
tion (via skin), injection (blood circulation), and inhalation (respiratory route). Currently, biophar-
maceuticals and conventional drugs are frequently incorporated into nanocarriers to direct their fate
in preferential pathways. Nanotechnology is believed to bring an elementary modification in manu-
facturing over the next few years and will have a dramatic impact on life sciences [39,40]. However,
it must be noted that this promising utilization of nanotechnology for advances in healthcare is
offset by the associated toxicity issues and potential adverse effects on human health. As a result of
their small size and unique physicochemical properties, the toxicological profiles of NPs may differ
considerably from those of larger particles composed of the same materials [41,42]. Furthermore,
NPs of different materials (e.g., gold, silica, titanium, CNTs, dendrimers, and quantum dots) are not
expected to interact with, or adversely affect, biological systems. Hence, the toxic potential of NPs
cannot be predicted by any single mechanism. Once entered into the body, nanotherapeutics can
interact with the local tissues and may provoke dysfunctions in the organs of contact [43]. These
