Breathing Polymersomes: CO₂‐Tuning Membrane Permeability for Size‐Selective Release, Separation, and Reaction

Abstract

Take a deep breath: The membrane permeability and the scale of membrane nanochannels of polymer vesicles are modulated by CO2 control of vesicular expansion and contraction. These polymersomes can act as size‐selective nanoseparators for particle sieving and as nanoreactors for enzymatic reactions that require compartmentalization. GSH=glutathione.

CO2-responsive polymeric materials: synthesis, self-assembly, and functional applications

“…60). 30 These polymersomes were able to drive enzymatic catalytic reactions by tuning the CO 2 stimulation times. 29 Upon bubbling CO 2 into the aqueous solution, the vesicles are expanded to 120 nm and their volume increases up to B800%.…”

“…CO 2 -switchable diblock copolymer PEO-b-PAD was synthesized by ATRP, which can self-assemble into vesicular aggregates with a size of B60 nm. 30 A subtlety of selecting monomers for CO 2 -switchable materials that is often not appreciated nor discussed in papers is the role of concentration of the protonatable groups under the intended conditions of CO 2 switching. This process is reversible and by removing CO 2 , the vesicles contract back to their initial size and morphology (Fig.…”

“…2 However CO 2 , which is a benign, inexpensive, abundant, and non-toxic trigger for stimuli-responsive materials, has received increasing attention in recent years. 5,6 Due to the very interesting properties of CO 2 as a trigger, CO 2 -responsive polymers have found potential applications in different areas including latexes, 7-13 gels, 14-17 CO 2 capturing and monitoring, [18][19][20][21][22][23] separation, 24 encapsulation, 25 forward osmosis, 26,27 CO 2 -switchable vesicles, [28][29][30][31] and CO 2 -switchable worm-like micelles. 4 Also, supercritical carbon dioxide (scCO 2 ), which is an environmentally friendly, non-flammable, and inexpensive solvent has found many new areas of interest in polymer synthesis due to the fact that as a polymerization medium it has negligible chain transfer and does not accumulate in the reaction.…”

Programmable Nanoassemblies from Non‐Assembling Homopolymers Using Ad Hoc Electrostatic Interactions

“…[3] Current focus in nanoassembly research has shifted from structure to function, where there is a need for strategies that afford assemblies that are not only structurally robust, but also are functionally programmable. [4] We have been interested in designing nanostructructures with conveniently addressable surfaces, dilution-independent morphological stability, and tunable cross-membrane molecular transport. We stipulated here that the transport barriers that control the cross-membrane molecular transport should be based on covalent sterics, rather than hydrophobicity.…”

Stimuli-responsive polymersomes and nanoreactors

“…17 Illustration of the compartmentalization of two enzymatic reactions in the PEG-b-PAD polymersomes modulated by CO 2 levels. 105 Recently, Palivan and co-workers created pH-responsive nanoreactors by a biomimetic strategy using synthetic membranes equipped with channel proteins, OmpF. 139 PMOXA 6 −PDMS 44 −PMOXA 6 polymersomes were modified with OmpF which was chemically modified with a pHresponsive molecular cap to serve as "gate".…”