Hollow Nanocapsules in Biomedical Imaging Applications - Nanotechnology for Biomedical Imaging and Diagnostics - page 93

4.4 Biomedical applicatioNs oF polymer NaNocapsules

The influence of capsules onto living cells have been studied recently addressing dif-
ferent aspects of interactions with living tissue [66], such as toxicity of capsules,
uptake kinetics and mechanisms, intracellular degradation, as well as strategies to
enhance or block the capsule uptake.
To enable biomedical applications of polymer NCs, it is important to know their
biocompatibility with living cell. NCs representing different scenarios of preparation
and handling can be taken up by human cells (Fig. 4.14) [67]. Among them, NCs with
an outer shell of lipids have the best cell penetration ability. Dried NCs may need
assistance with dispersions in aqueous media, for example, with mild surfactants. All
investigated polymer NCs showed no inhibition of cell proliferation at a dose up to
200 mg/ml or up to 0.2% by volume. At this dose, no generation of reactive oxygen
species (ROS), induction of apoptosis, or perturbation of cell cycle is detected.

(a) NC1 NC2 NC3

50 μg/ml 50 μg/ml 50 μg/ml

10e0 10e1 10e2 10e3 10e0 10e1 10e2 10e3 10e0 10e1 10e2 10e3

200 μg/ml 200 μg/ml 200 μg/ml

10e0 10e1 10e2 10e3 10e0

Green fluorescence intensity

10e1 10e2 10e3 10e0 10e1 10e2 10e3

(b)

Figure 4.14 Cell uptake of NCs in A549 cell. Cell internalization was measured by flow
cytometry (a) and confocal laser scanning microscopy (CLSm) (excitation at 488 nm) (b). In
CLSm experiments, cell culture medium (a) or NC1 (b), NC2 (c), or NC3 (d) was incubated
with cells for 24 h before measurements. (Adapted with permission from Ref. [67]. © Royal
Society of Chemistry.)