of nanostructures can be developed as a general means to
lowering the cytotoxicity of amphiphilic nanostructures.
As the nanostructure of 1 is decorated with CPPs, it might
be used as an intracellular drug carrier following encapsula-
tion of hydrophobic drugs. It would be quite interesting
to investigate how CPP-decorated 2D macroscopic sheets
interact with the cells. For this, a model hydrophobic drug,
Nile Red, was encapsulated in the polymerized nanostructure
of 1, and the Nile Red-encapsulated nanostructure was treated
in mammalian cells. The result showed that the nanostructure
of 1 was quite efficient in delivering encapsulated cargos into
the cells. Especially, the successful intracellular delivery of the
nanostructures of 1 demonstrates that macroscopic 2D sheets
interact with the outer cell membrane strongly and deliver the
guest molecules efficiently into the cells (Fig. 3b). It is not
currently clear whether the 2D sheet itself does internalize into
the inside of the cells or, due to its very large size, the sheet just
releases the payloads while it is still bound to the cell surface,
which will be the subject of further in depth study. The
macroscopic 2D sheets, contrary to conventional spherically
or cylindrically-shaped nanostructures, should offer a unique
opportunity for developing nanocarriers with unexplored and
unexpected functions.
Technology (MEST). K.-S.M., E.L. and Y.-b.L also thank the
BK21 program of MEST.
Notes and references
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1
In conclusion, we have demonstrated that polymerizable Tat
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can be covalently fixed to produce molecular sheets, which would
open new possibilities for fabricating morphologically diverse and
controlled bioactive nanostructures. Subsequently, covalent cap-
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cargo molecules in concentrations quite below their CMCs.
We gratefully acknowledge the National Creative Research
Initiative Program of the Ministry of Education, Science and
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This journal is ꢀc The Royal Society of Chemistry 2008
Chem. Commun., 2008, 4001–4003 | 4003