Increasing the Resistance of Living Cells against Oxidative Stress by Nonnatural Surfactants as Membrane Guards

Abstract

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)constituent 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 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.

Aggregation‐Induced Improvement of Catalytic Activity by Inner‐Aggregate Electronic Communication of Metal‐Fullerene‐Based Surfactants

“…In these aggregates the polar metal‐fullerene complex, which serves as head group to the surfactant, align side by side at the outside of the bilayer. This general structuration was reported before for fullerene‐based surfactants . That this alignment is indeed the case a zetapotential measurement was performed.…”

“…Our group has specialized in the synthesis of surfactants equipped with functional, metal‐containing head groups, and several examples of catalytically active surfactants have already been published by us . Important preliminary work of relevance to the current work is centered on fullerene‐based surfactants that evaluated their self‐assembly behavior and the related beneficial effect of self‐assembly on their properties …”

Molecular Semiconductor Surfactants with Fullerenol Heads and Colored Tails for Carbon Dioxide Photoconversion

“…To realize such surfactant properties, we chose a so‐called fullerenol as the head group as they are known to show similar electronic behavior as unmodified fullerenes and to be water‐soluble . We have recently presented surfactants with fullerenol head groups and alkyl tails and tested their biocompatibility . In Ref.…”

Molekulare Halbleiter‐Tenside mit Fullerenol‐Kopfgruppe und Farbstoffketten für die photokatalytische Umwandlung von Kohlenstoffdioxid

“…Aufgrund des relative großen Packungsparameters der Tenside (siehe Abbildung S1) verhalten sie sich ähnlich wie Lipide und bevorzugen Strukturen mit geringer Krümmung. Diese Beobachtung steht im Einklang mit unseren bisherigen Ergebnissen für Fullerenol‐Tenside . Obwohl die Größe, Form und Polarität der drei Verbindungen nach den Strukturberechnungen ähnlich ist (Abbildung S1), sieht man, dass FuDy‐B bei Absättigung der Oberfläche ( c >0.5 m m ) stärker oberflächenaktiv ist als FuDy‐Y und FuDy‐R .…”