Fusogenic Metallosupramolecular Brush Vesicles

Supramolecular chemistry combined with polymer chemistry, which utilized the weak interaction between molecules, such as electrostatic interaction, metal ion coordination, hydrogen bonding, π-π stacking interaction and hydrophobicity interaction to build a star-shaped polymers, block polymers, cross-linked polymers, and other complex macromolecules, is one of the research hotspot in the field of polymer. Generally, supramolecular polymer shows responses to external stimuli such as light, electricity, acid-base, and is environment responsive polymer, which makes them potential applications in transport and release of drug, preparation of novel materials.Metal ion coordination has been used to build metallosupramolecular polymer. For the roles of metals, such polymer is capable of improving the process of electron transfer, magnetic, catalytic reaction, and the redox ability of the polymer, and is good foundation stone of new optoelectronic material.Electrostatic self-assembly is one of the most common methods to build supramolecular polymer. Such method has is own shortcomings. However, compared to other supramolecular, this kind of supramolecular has the advantages such as the easy preparation, various functions, the weak binding and dissociation in polar solvents which can lead to good reversibility. Therefore, the supramolecular based on electrostatic assembly has been a hot research. As two kinds of classical graft polymers, star-and brush-polymer have been researched for many years. Hydrogen bonds, host-ghost recognition, metal ion coordination, electrostatic interaction and other weak interactions have been utilized to synthesis star polymers, but the phenomenon that non-covalent interactions except host-ghost recognition are utilized to design and prepare polymer brush has not been reported.In summary, we have fabricated supramolecular brushes by the electrostatic self-assembly of Fe-MSP with ST-Sn. The resultant MSBs can self-assemble into vesicles in chloroform/methanol (v/v=1) mixture solvents, which further shows a spontaneous fusion into larger vesicles with an hour-scale fusion time. With this much longer fusion process, the arrow-like protrusion, stalk intermediate, and hemifusion diaphragm are clearly observed by TEM. The driving force is believed to be the lateral tension generated by the bending of the rigid-rod Fe-MSP in the vesicles.We hope that these studies can not only help scientists to prepare novel functional supramolecular brush, but also can provide theoretical support to research cellular fusion.