mt8b00323_si_001.pdf (1.94 MB)
Visualizing the Solid–Liquid Interface of Conjugated Copolymer Films Using Fluorescent Liposomes
journal contribution
posted on 2018-10-15, 00:00 authored by Yi Zhang, Achilleas Savva, Shofarul Wustoni, Adel Hama, Iuliana P. Maria, Alexander Giovannitti, Iain McCulloch, Sahika InalConjugated polymers
are promising engineering tools for establishing
bilateral electrical communication with living systems. The free energy
of their films, the roughness, and charge density play major roles
in determining their interactions with lipid bilayers, which form
the membrane barrier around every living cell allowing for molecular
exchange with the extracellular environment. In this work, we investigate
lipid bilayer formation from synthetic lipid vesicles (liposomes)
on a series of amphiphilic copolymer films based on naphthalene 1,4,5,8
tetracarboxylic diimide bithiophene (NDI-T2) backbone where the alkyl
side chain is gradually exchanged for an ethylene glycol-based side
chain. As the concentration of ethylene glycol in the composition
changes, the surface energy of the films varies drastically, which,
in turn, effects the interactions with liposomes. By imaging the interactions
of fluorophore-labeled liposomes with these surfaces via a fluorescence
microscope, we show that the films can be cast such that ethylene
glycol-rich regions, which liposomes favor, are accumulated on the
surface and extract information on the wettability behavior that has
not been possible using other surface sensitive techniques. This approach
uncovers the solid/liquid interface of a promising class of electron
transporting conjugated polymer films and suggests synthetic strategies
to maximize the number of lipid-polymer contacts for the formation
of supported lipid bilayers.