2 research outputs found
Increasing the Resistance of Living Cells against Oxidative Stress by Nonnatural Surfactants as Membrane Guards
The importation of
construction principles or even constituents from biology into materials
science is a prevailing concept. Vice versa, the cellular level modification
of living systems with nonnatural components is much more difficult
to achieve. It has been done for analytical purposes, for example,
imaging, to learn something about intracellular processes. Cases describing
the improvement of a biological function by the integration of a nonnatural
(nano)Âconstituent are extremely rare. Because biological membranes
contain some kind of a surfactant, for example, phospholipids, our
idea is to modify cells with a newly synthesized surfactant. However,
this surfactant is intended to possess an additional functionality,
which is the reduction of oxidative stress. We report the synthesis
of a surfactant with Janus-type head group architecture, a fullerene
C<sub>60</sub> modified by five alkyl chains on one side and an average
of 20 oxygen species on the other hemisphere. It is demonstrated that
the amphiphilic properties of the fullerenol surfactant are similar
to that of lipids. Not only quenching of reactive oxygen species (superoxide,
hydroxyl radicals, peroxynitrite, and hydrogen peroxide) was successful,
but also the fullerenol surfactant exceeds benchmark antioxidant agents
such as quercetin. The surfactant was then brought into contact with
different cell types, and the viability even of delicate cells such
as human liver cells (HepG2) and human dopaminergic neurons (LUHMES)
has proven to be extraordinarily high. We could show further that
the cells take up the fullerenol surfactant, and as a consequence,
they are protected much better against oxidative stress
Locally Resolved Membrane Binding Affinity of the N-Terminus of α-Synuclein
α-Synuclein is abundantly present in Lewy bodies,
characteristic
of Parkinson’s disease. Its exact physiological role has yet
to be determined, but mitochondrial membrane binding is suspected
to be a key aspect of its function. Electron paramagnetic resonance
spectroscopy in combination with site-directed spin labeling allowed
for a locally resolved analysis of the protein–membrane binding
affinity for artificial phospholipid membranes, supported by a study
of binding to isolated mitochondria. The data reveal that the binding
affinity of the N-terminus is nonuniform