Dendrimer‐Based Polyion Complex Vesicles: Loops Make Loose

• Published in: Macromolecular rapid communications. 2022-01, Vol.43 (2), p.e2100594-n/a
• Main Authors: Huang, Jianan, Li, Chendan, Gao, Yifan, Cai, Ying, Guo, Xuhong, Cohen Stuart, Martien A., Wang, Junyou
• Format: Article
• Language: English
• Subjects: Assemblies; Block copolymers; Cations; Dendrimers; dynamics; Ethylene oxide; loops; Micelles; Morphology; PAMAMs; Parameters; Polyethylene Glycols; polyion complex vesicles; Polymers; Styrene; triblock copolymers; Vesicles
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.202100594

Associations of amphiphiles assume their various morphologies according to the so‐called packing parameter under thermodynamic control. However, one may raise the question of whether polymers can always relax fast enough to obey thermodynamic control, and how this may be checked. Here, a case of polyion complex (PIC) assemblies where the morphology appears to be subject to kinetic control is discussed. Poly (ethylene oxide)‐b‐(styrene sulfonate) block copolymers are combined with cationic PAMAM dendrimers of various generations (2–7). The PEO‐PSS diblocks, and the corresponding PSS‐PEO‐PSS triblocks should have nearly identical packing parameters, but surprisingly creat different assemblies, namely core‐shell micelles and vesicles, respectively. Moreover, the micelles are very stable against added salt, whereas the vesicles are not only much more sensitive to added salt, but also appear to exchange matter on relevant time scales. The small and largely quenched early‐stage precursor complexes are responsible for the morphological and dynamic differences, implying that kinetic control may also be a way to obtain particles with well‐defined and useful properties. The exciting new finding that triblocks produce more “active” vesicles will hopefully trigger the exploration of more pathways, and so learn how to tune PICsomes toward specific applications. Co‐assembly of amine‐terminated PAMAM dendrimers with PSSn‐PEOm‐PSSn triblock copolymer creates a new type of polyion complex (PIC) vesicles with not only multiple compartments, but also unexpected dynamic properties, which enables them to exchange components with each other. The exciting new finding “active” vesicles will hopefully trigger the exploration of more pathways toward specific applications of PICsomes.