Biomedical Engineering Reference
In-Depth Information
patches may have applications in tissue regeneration [94]. Stem cells have
been shown to selectively target injured brain and spinal cord tissue and
improve functional recovery. h e development of biologically compatible
nanoi ber scaf olds that mimic the structure of the extracellular matrix can
serve as a permissive bridge for axonal regeneration or as a drug delivery
system. h e incorporation of biologically active epitopes and/or the uti-
lization of these scaf olds as stem cell carriers may further enhance their
therapeutic ei cacy [95]. Kim
et al.
have prepared a series of G3 polyami-
doamine (PAMAM) dendrimers derivatized with Alexa Fluor 488, vary-
ing numbers of PEG(550)/PEG(750)/PEG(2000), and nucleoside moieties
derived from the A(2A) adenosine receptor (AR) agonist CGS21680(2-[4-
(2-carboxylethyl)phenylethylamino]-5'-N-ethylcarboxamidoadenosine),
and demonstrated the feasibility of using short PEG chains in the design of
carriers that target ligand-receptor interactions [96].
Surface-functionalized mesoporous silica nanoparticles (MSNP) can
be used as an ei cient and safe carrier for bioactive molecules. Xia
et al.
have demonstrated that the enhanced cellular uptake of the nontoxic cat-
ionic MSNP enhances the delivery of the hydrophobic anticancer drug,
paclitaxel, to pancreatic cancer cells. h is novel use of a cationic MSNP
extends its therapeutic use potential [97]. Well-ordered SrTiO
3
nanotube
arrays capable of Sr release at a slow rate and for a long time were suc-
cessfully fabricated on titanium by simple hydrothermal treatment of
anodized titania nanotubes by Xin
et al.
Ti-based implant with SrTiO(3)
nanotube arrays is an ideal candidate for osteoporotic bone implants. h e
proposed method can also be extended to load other biologically useful
elements such as Mg and Zn [98]. Layered double hydroxides (LDHs) are
now known for their application in nanomedicine. h e LDH nanoparticles
have been used in gene and drug delivery and proposed for the internal-
ization of LDH nanoparticles into cells along with the intracellular fate of
the particles and their cargo [99]. Cirstoiu-Hapca
et al.
have developed
Paclitaxel (Tx)-loaded anti-HER2 immunonanoparticles (NPs-Tx-HER)
by the covalent coupling of humanized monoclonal anti-HER2 antibodies
(trastuzumab, Herceptin) to Tx-loaded poly(dl-lactic acid) nanoparticles
(NPs-Tx) for the active targeting of tumor cells that overexpress HER2
receptors [100]. h e synthesis of protein dendrimers using a strong but
noncovalent interaction between a peptide and complementary protein is
proposed as an ei cient strategy to arrive at dendrimers fully functional-
ized with protein domains. h e noncovalent synthetic strategy provides
access to well-dei ned, dynamic, semisynthetic protein assemblies in high
yield and is therefore of interest to the i eld of nanomedicine as well as
biomaterials [101]. Multifunctional nanomedicine is emerging as a highly
