E17_O10 Supramolecular hierarchical self

E17_O10
Supramolecular hierarchical self-assemblies based on polypeptide complexes
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Nikolay Houbenov , Sirkku Hanski , Susanna Junnila , Johannes Haataja , Antti Soininen ,
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Janne Ruokolainen , Hermis Iatrou , Nikos Hadjichristidis , Charl Faul , Olli Ikkala
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Helsinki University of Technology/Aalto University, Department of Applied Physics, P.O. Box
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5100, 02150 Espoo, Finland, University of Athens, Department of Chemistry,
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Panepistimiopolis Zografou, 15771 Athens, Greece, University of Bristol, School of
Chemistry, BS81TS Bristol, United Kingdom
For materials scientists, polypeptides offer a rich toolbox to tune the self-assemblies in
comparison to the synthetic polymers, still not incorporating the full biomaterials complexity of
proteins. In this talk, some of our recent approaches based on polypeptide and block
copolypeptide complexes are described. Polylysine (PLL) is a feasible model polypeptide, as
it allows both α-helical and β-sheet secondary structures. We show evidence that by proper
side chain crowding by surfactant complexation and surfactant architecture, one can switch
the secondary structures using a thermal pulse.(1-2) By incorporating Janus type surfactants,
exceptionally well defined self-assembled hierarchies can be obtained (see Figure).(3) The
final example deals ionic complexes with deoxyguanosine monophosphates (dGMP). Upon
ionic complexation of dGMP with a triblock copolypeptide polylysine-b-polybenzylglutamate-bpolylysine (PLL-b-PBLG-b-PLL), nanoribbons are formed with several length scales of order,
where dGMPs form guanine quadruplexes.(4) By contrast, for dGMP complexed with a
diblock copolypeptide PLL-b-PBLG, space filling self-assemblies are formed.(5) At the largest
length scale, lamellar assembly is obtained with alternating PBLG and PLL/dGMP domains
(see Figure). Most interestingly, the dGMPs form hydrogen bonded ribbons within the
PLL/dGMP domains. They promote to stabilize porosity within the domains. In summary, the
approaches show that complex self-assemblies at higher orders of hierarchies are available
using rational approaches based on biological motifs.
Figure. Polylysine (PLL) ionically complexed with Janus-type phospholipids containing
polyethylene chains, leading to highly ordered self-assembled hierarchy (left). Polylysine-bpolybenzylglutamate
(PLL-b-PBLG)
ionically
complexed
with
deoxyguanosine
monophosphates (dGMP), leading to self-assembled hierarchies and framework-like porosity
(right).
1.Hanski, S.; Junnila, S.; Almásy, L.; Ruokolainen, J.; Ikkala, O. Macromolecules, 2008, 41,
866.
2.Junnila, S.; Hanski, S.; Oakley, R. J.; Nummelin, S.; Ruokolainen, J.; Faul, C. F. J.; Ikkala,
O. Biomacromolecules 2009,10, 2787.
3.Hanski, S.; Junnila, S.; Soininen, A.; Ruokolainen, J.; Ikkala, O. Macromolecules, submitted.
4.Houbenov, N.; Nykänen, A.; Iatrou, H.; Hadjichristidis, N.; Ruokolainen, J.; Faul, C.F.J.;
Ikkala, O Adv. Funct. Mat. 2008, 18, 2041.
5.Houbenov, N.; Haataja, J.; Iatrou, H.; Hadjichristidis, N.; Ruokolainen, J.; Faul, C. F. J.;
Ikkala, O. submitted.