Chemistry Reference
In-Depth Information
Also still under investigation for use as drug delivery systems are the so-called
polymersomes. Polymersomes consist of a double layer of polymers with a hydro-
philic and a hydrophobic function, cross-linked by various polymers. The
combinations form a hollow sphere, comparable with the structure of liposomes
from which the name polymersome derives. Their size can be varied between
100 nm and 100
ΚΌ
m[
221
]. They are able to transport bioactive molecules to the
relevant cells and to release them there [
222
].
6 Summary
This review has summarized relevant aspects on the properties and the bioresponse
of AuNPs in the context of a rapidly growing field of applications, i.e., the
application in vivo and in vitro for medical purposes. It has been shown by a
number of selected examples that most of the AuNPs synthesized so far are
considered nontoxic, making them suited for in vivo applications, e.g., for imaging
and therapy. Special focus is laid on AuNPs in the sub-2 nm range, which under
certain conditions can become toxic. This sheds light on how adverse effects of
AuNPs in biological systems may occur and, at the same time, suggests how such
toxic effect may be used in therapy as well. The present state of knowledge is
summarized on the mechanism how such small AuNPs may interact with
biomolecules and cells, addressing the effect of shape complementarity in the
sense that AuNPs approach the size of biological molecules and subcellular
structures and thus may even behave as molecular ligands.
It becomes evident that the high degree of control over particle size and ligand
chemistry opens up an avenue of novel applications in a biological environment.
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