Flow chemistry controls self-assembly and cargo in Belousov-Zhabotinsky driven polymerization-induced self-assembly

Abstract

Amphiphilic block-copolymer vesicles are increasingly used for medical and chemical applications, and a novel method for their transient self-assembly orchestrated by periodically generated radicals during the oscillatory Belousov-Zhabotinsky (BZ) reaction was recently developed. Here we report how combining this one pot polymerization-induced selfassembly (PISA) method with a continuously stirred tank reactor (CSTR) strategy allows for continuous and reproducible control of both the PISA process and the chemical features (e.g. the radical generation and oscillation) of the entrapped cargo. By appropriately tuning the residence time (τ), target degree of polymerization (DP) and the BZ reactants, intermediate self-assembly structures are also obtained (micelles, worms and nano-sized vesicles). Simultaneously, the chemical properties of the cargo at encapsulation are known and tunable, a key advantage over batch operation. Finally, we also show that BZ-driven polymerization in CSTR additionally supports more non-periodic dynamics such as bursting.

Photochemically Induced Cyclic Morphological Dynamics via Degradation of Autonomously Produced Self-Assembled Polymer Vesicles

“…(present in our PISA systems) are two photocatalysts well-known to be sensitive to photobleaching. 47,48 As expected, in Fig. 3b and c, we show that both photocatalysts are indeed vulnerable to degradation when irradiated with blue light in an oxygen-rich environment, and show reductions in their absorbance peak intensities of 24% and 22% respectively.…”

In-vitro reconfigurability of native chemical automata, the inclusiveness of their hierarchy and their thermodynamics

“…This can be done by exploiting the high reactivity of BZ with many chemical species, including organic compounds, inorganic salts, monomers, etc. Indeed, BZ has been coupled to polymerization reaction 22 and polymerization-induced self-assembly [23][24][25] .…”

PISA: construction of self-organized and self-assembled functional vesicular structures

“…4C). 29 A continuously stirred tank reactor (CSTR) was used to ensure the homogeneity of the BZ oscillations, such as the amplitude, periodicity and shape, preventing stationary space-periodic structures from occurring. Polymerization of DAAM from a trithiocarbonate PEG mCTA using BZ-RAFT-PISA yielded spherical micelles, worms, nanoand giant-sized vesicles, dependent on the residence time, BZ oscillation periodicity and the DPn of the DAAM core-forming block.…”

“…These, in turn evolve in a morphology sequence controlled by the chemical nature of the PISA reaction and the environment into which it takes place. Furthermore, since chemical reactions can be thought of as events of molecular recognition 25 one can begin to envisage [26][27][28][29] how PISA can potentially enable an extraordinary scenario for molecules recognizing molecules and use the sequences into which these molecules react to build material structures which can accomplish tasks or functions in a programmed fashion.…”