Biomedical Engineering Reference
In-Depth Information
(a)
(b)
(c)
(d)
(e)
(f )
FIGURE 10.2
TEM images of 80 nm sections of HepG2 cells treated with AgNPs. AgNPs are visible in
the cells as black and electron-dense spots indicated by arrows. Panels (a) and (b) are representative images
of untreated controls and panels (c), (d), (e), and (f) are representative images of cells treated with 1 μg/mL
AgNPs for 24 h. Scale bars represent 1 μm in panel (c), 200 nm in panel (d), and 2 μm in panels (a), (b), (e),
and (f). (Reprinted with permission from Kim, S. et al. 2009.
Toxicol. In Vitro
. 23, 1076 -1084.)
in a single experiment. The data from microarray technology help to develop a more complete
understanding of gene expression, which can be used for transcriptional regulation and interactions
as well as functional genomics. However, the data should be verified by substantial complementary
investigations. Dua et al. (2011) performed DNA microarray analysis of HEK293 cells exposed to
IC20 concentrations of Fe
2
O
3
, MCM-41, and ZnO NPs for 24 h, finding that both Fe
2
O
3
and MCM-
41 induced the expression of many genes encoding for 40S and 60S ribosomal protein homologs as
well as histones involved in chromatin remodeling, while ZnO resulted in the altered expression of
many genes involved in cell death and apoptosis. In addition, following real-time PCR, the changes
in the expression of eight selected genes were validated. Although microarray technology is very
successful
in vitro
studies, its exploitation is questioned in
in vivo
investigations, since it can be con-
founded by a number of variables, such as the type of target organ, the effects of pharmacokinetics,
and/or pharmacodynamics parameters.
FIGURE 10.3
Scanning electron microscopy of live cells exposed to nanoparticles (a) and micron-sized
particles (b) of CoCr for 24 h and viewed in quantomix capsules. Scale bars represent 10 μm. (Reprinted with
permission from Papageorgiou, I., Brown, C., Schins, R. et al. 2007.
Biomaterials
. 28, 1946 -1958.)
