Biomedical Engineering Reference
In-Depth Information
dendrimers, polymeric and ceramic nanoparticles, protein cage archi-
tectures, viral-derived capsid nanoparticles, polyplexes, and liposomes.
h erapeutic and diagnostic agents can be encapsulated, covalently
attached, or adsorbed into such nanocarriers. h e reduced particle size
entails high surface area, and hence is a strategy for faster drug release.
Some of the carriers can be engineered in such a way that they can be
activated by changes in the environmental pH, chemical stimuli, by the
application of a rapidly oscillating magnetic i eld, or by application of an
external heat source. Multifunctional NPs and micellar encapsulation of
QDs have signii cant applications in biological environments. Lin
et al.
have evaluated ferritin nanocages as candidate nanoplatforms for multi-
functional loading. Ferritin nanocages can be either genetically or chemi-
cally modii ed to impart functionalities to their surfaces, and metal cations
can be encapsulated in their interiors by association with metal binding
sites. Moreover, dif erent types of ferritin nanocages can be disassembled
under acidic conditions and reassembled at pH of 7.4, providing a fac-
ile way to achieve function hybridization. Ferritin particles are a powerful
nanoplatfom in the era of nanomedicine [87]. Ei cient and site-specii c
delivery of therapeutic drugs is a critical challenge in the clinical treatment
of cancer. Enhancement can potentially be achieved by conjugation of tar-
geting ligands onto nanocarriers to achieve selective delivery to the tumor
cell or the tumor vasculature. A variety of ligands have been investigated
including folate, transferrin, antibodies, peptides and aptamers. Multiple
functionalities can be incorporated into the design of nanoparticles, e.g.,
to enable imaging and trigger intracellular drug release [88]. h e grat -
ing of drugs to the single-walled carbon nanotube (SWCNT) was attained
by the initial conversion of carboxylic groups in SWCNT to correspond-
ing acyl chlorides. h e active acyl chlorides in SWCNT were subsequently
mixed with chemotherapeutic agents having NH, NH
2
, and OH functional
groups to af ord the formation of relevant amide and ester, respectively.
h e drugs covalently grat ed to SWCNT were identii ed by infrared and
UV-visible spectroscopy and transmission electron microscopy methods.
From a clinical aspect, the grat ing of drugs to the SWCNT can be used as
a new tool and useful method for potential drug delivery in patients [89].
Mesoporous silicon particles show great promise for use in drug deliv-
ery and imaging applications as carriers for second-stage nanoparticles and
higher-order particles or therapeutics. Modulation of particle geometry,
surface chemistry, and porosity allows silicon particles to be optimized for
specii c applications such as vascular targeting and avoidance of biological
barriers commonly found between the site of drug injection and the i nal
destination. h e concept of multifunctional nanocarriers is one in which
