Biomedical Engineering Reference
In-Depth Information
the surface chemistry of the particles to present either dextran or albumin had an
effect on cell behavior and morphology [48, 49]. Berry
et al
. demonstrated that the
exposure of cells to 7 - 15 nm dextran - coated particles signifi cantly delayed cell
spreading in comparison to the cells-only control. Dextran-coated particles stimu-
lated a far greater cell membrane disruption (associated with endocytosis) than
plain, non-coated particles, even though the level of uptake was similar. Further
cytoskeletal staining demonstrated that F - actin and beta - tubulin were structurally
responsible for these membrane disruptions. Gupta and Curtis have shown that
the surface modifi cation of poly(ethylene glycol) ( PEG ) - coated magnetic nanopar-
ticles affects fi broblast adhesion/viability, morphology, particle uptake and cyto-
skeletal organization differently to uncoated particles [50] . The PEG - coated particles
demonstrated a signifi cantly higher cell adhesion and cellular uptake in compari-
son to the uncoated particle controls. The use of insulin, lactoferrin, cerruloplas-
min and pullulan as surface coatings for magnetic particles in order to prevent
endocytosis have also been investigated [51 - 53] .
Ito
et al.
have shown that human keratinocytes (HaCaT cell line) attach to posi-
tively charged and Arg - Gly - Asp ( RGD ) - coated magnetic particles, and can be
infl uenced to form layers
in vitro
when a magnetic fi eld is placed under the dish
(the culture surface of which was coated with a negatively charged hydrogel) in
order to attract the cell/particle suspension [54]. Cell patterning was created by
using a magnetic fi eld and a 200
m-wide stainless steel plate beneath the culture
surface, while cell adhesion, spreading and fi bronectin production was observed
with the RGD- coated particles.
μ
8.2.4
Lung
Maruyama
et al.
have used nanoscale biogenic magnetite to detect mutations in
the epidermal growth factor receptor (EGFR) gene in non-small lung cancer cells
[55]. The magnetic particles were isolated from magnetotactic bacteria and conju-
gated to streptavidin. Biotin-labeled PCR products then were bound to the mag-
netic material and fl uorescently labeled. An early detection (3.5 h) was reported for
EGFR
gene mutations.
Lung cancer cells have been transfected with the gene
Lac Z
, and tagged using
green fl uorescent protein (GFP), by using Fe
3
O
4
nanoparticles [56]. The particle
size, including the gene/virus, was less than 100 nm, and no particle-related toxic-
ity was observed. The particles plus viral delivery of the
Lac Z
gene, when exposed
to magnetic fi elds, demonstrated a much higher transfection effi ciency when
compared to traditional transfection with liposomes or lipofectamine.
8.2.5
Eye
Formanek
et al.
have described an effi cient method for isolating human oral kera-
tinocytes using magnetic cell separation techniques [57]. In order to study human
