Strategies to Prevent Bacterial Adhesion on Biomaterials - Biomimetics: Advancing Nanobiomaterials and Tissue Engineering - page 179

may be stored for long periods of time as an aqueous suspension lacking
agglomeration, yet, they do not reveal signifi cant antibacterial properties
[89]. It is reported that iron oxide particles work as Fenton's reagent (Fe 2+ /
Fe 3+ in solutions), where iron oxide particles react with hydrogen peroxide
and turn out hydroxyls as well as peroxide radicals [90].
Gupta et al. reported the reduction of cytotoxicity and improved cel-
lular uptake of superparamagnetic iron oxide nanoparticles (SPION) of
average size (13.6 nm) by surface modifi cation with pullulan (Pn). The
average particle size of Pn modifi ed SPIONS was found around 42 ± 2.5

nm. Cell culture was carried out with infi nity telomerase − immortalized

primary human fi broblast cells (hTERT − BJ1). Figure 7.18 shows a dose −

dependent toxicity of SPION treated cells incubated for 24 h. Cell viabil-

ity was reduced up to 80% of control at the 0.05 mg/ml concentration of
SPION, and such reductions increase at higher concentrations. Pn

−

SPION
exhibited ~ 92% cell viability even at highest concentration (2.0 mg/ml).
The results of cell culture experiments have indicated that cellular uptake
of SPIONs can be enhanced by its surface modifi cation with pullulan,
which is noncytotoxic. In particular, pullulan was internalized by cells via
a different route than the SPION endocytosis. Pullulan modifi ed iron oxide
nanoparticles are therefore suggested for imaging of target imaging [91].
Dalai et al. reported the infl uence of light (UV

−

− illuminated) on the tox-

icity of TiO 2 nanoparticles (50 − 200 nm) at concentration of 0.05 μ g/mL to

1 dependent decrease

in the bacterial cell viability was found by standard plate count and MTT
assays; such a decrease was found unaffected in the presence of light for
low concentration and 2 h exposure. Intracellular ROS generation, an
important cause of cell death, was found to be signifi cantly increased
when bacteria were incubated with TiO 2 nanoparticles under the light.

μ g/mL for Bacillus licheniformis bacteria. The dose −

120

Pn-SPION

100

80

60

Uncoated SPION

40

20

0

0 500 1000 1500 2000 2500

Concentration ( m g/ml)

Figure 7.18 Cytotoxicity profi le of SPION and Pn SPION when incubated with

human fi broblast as determined by MTT assay [91]. (Copyright (2013), with
permission from Elsevier)

−