Tailoring the interfacial assembly and the mechanical response of colloidal and biological systems
DIPC Seminars
- Speaker
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Armando Maestro, Institut Max von Laue - Paul Langevin ILL, France
- When
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2020/12/02
17:00 - Place
- Online seminar, Donostia International Physics Center
- Add to calendar
-
iCal
Fluid interfaces can be used as a platform for promoting the direct and
spontaneous self-assembly of colloidal systems, including amphiphilic
molecules, macromolecules and organic and metallic nanoparticles, where the
driving force is the reduction in interfacial energy. Besides, fluid
interfaces allow fine-tuning of the ensemble of molecules by an external
force, such as the presence of an imposed interfacial flow, or by engineering
the molecular interactions dictated by the interplay of interfacial forces. As
a consequence, a wide-ranging set of interfacial structures can be achieved:
from liquid-like layers, which can flow under stress, to amorphous solids that
can sustain static stress [1].
In this talk, I will first discuss different ways of quantitatively tuning and
tailoring the mechanical response and the interfacial assembly of colloidal
systems confined at fluid interfaces. In particular, I will focus on the link
between the structure, measured by neutron reflectivity and ellipsometry, and
the mechanical properties (employing different shear probes) of different
versatile systems that we have studied lately: Ligand-coated spherical silica
nanoparticles, synthetic soft microgel particles (based on chemically cross-
linked acrylamide polymers), graphene oxide sheets, and very recently
surfactant/polyelectrolyte mixtures and lipid nanoparticles.
In the second part of the talk, I will report different experimental
investigations involving phospholipids and proteins (or peptides) recreating,
by in vitro models studied by neutron scattering, relevant biophysical
processes happening at biomembrane surfaces. For example, the first stage of
endocytosis [2], by studying the composition, structure and mechanics of a
complex layer formed by protein/lipids that self-assembles in stages
generating membrane curvature. And, very lately the viral fusion mechanism
[3].
References
[1] A. Maestro, Current Opinion in Colloid and Interface Science, 2019, 39,
232;
[2] Kelly BT and Owen DJ, Science, 2014, 345, 459.
[3] L. Du et al., Nature, 2009, 7, 226.
Host: Juan Colmenero
ZOOM: