Image-Based High-Content Analysis, Stem Cells and Nanomedicines: A Novel Strategy for Drug Discovery - Harnessing Biomaterials in Nanomedicine: Preparation, Toxicity, and Applications - page 274

the entry of many nutrients, such as amino acids, nucleosides, and
glucose [83-85].
Nano-carriers can facilitate passage beyond the BBB in various
ways. Some nanoparticles have a local toxic eff ect at the brain
vasculature, which leads to a partial permeability of the endothelial
cells [86]. Some nanoparticles can open the tight junctions between
endothelial cells and allow the drug to penetrate either in free form
or together with the carrier [87]. There are also nanoparticles that
mediate transcytosis through the endothelial cell layer [88].
Not only are there high numbers of possible carriers, but each
carrier type can usually be constructed by a variety of molecules as
long as these molecules have similar characteristics. For example,
a liposome can be constructed from a huge variety of naturally
occurring or modified phospholipids, or even a combination of
diff erent phospholipids in a single liposome. To add an additional
level of complexity, each carrier is capable of transporting a huge
variety of therapeutic agents.
Because of the immense combinatory options in this promising
field, we suggest a novel approach by which to hasten the much-
needed progress in this area. In a similar fashion to how high-
throughput and high-content screening have revolutionized the
way in which we search for standard drugs, the application of
these methods using human stem cells to the developing field of
nanomedicines has the potential to lead to the next big breakthrough
in the pharmaceutical industry.
9.7 ConcludingRemarks
The common denominator in most in vitro drug discovery applications
is the biological component whose functionalities and responses to a
battery of compounds are being assayed. There is a substantial need
for physiological cell models and, in particular, for efficacy and safety
studies. The properties of stem cells that make them so attractive for
use for these studies too lie in their ability to produce a variety of
specific cell types that can be used for cell-specific assays.
Concomitantly, the introduction of nanomolecules may conduce
to improving therapies by allowing, for example, the delivery of drugs
directly to the desired target. The combination of both technologies,
image-based HCS and nanomolecules, using stem cells as target
for the study, is expected to contribute to improve current therapy