A general method to greatly enhance ultrasound-responsiveness for common polymeric assemblies

Abstract

Ultrasound-controlled drug release is a very promising technique for controlled drug delivery due to the unique advantages of ultrasound as the stimulus.

Fabrication of the Polymersomes with Unique and Even Nonequilibrium Morphologies

“…For preparing the big vesicles that can undergo osmotically induced shape transformation, we synthesized amphiphilic block copolymer poly( N , N ‐dimethylaminoethyl methacrylate)‐ block ‐poly{benzyl methacrylate‐ co ‐4‐methyl‐[7‐(methacryloyl)oxy‐ethyl‐oxy]coumarin} (PDMAEMA‐ b ‐P(BzMA‐ co ‐CMA), containing photo‐crosslinkable coumarin groups (CMA) in the P(BzMA‐ co ‐CMA) block (the random copolymer of BzMA and CMA), by reversible addition‐fragmentation chain transfer polymerization according to the procedures reported in our previous work. [ 14 ] For polymer 1 , the average numbers of the repeat units of PDMAEMA and P(BzMA‐ co ‐CMA) blocks were measured by 1 H NMR to be 92 and 478‐ co ‐50, respectively; the polydispersity measured by gel permeation chromatography is 1.25 (Figure S1 and Table S1, Supporting Information). The self‐assembly was conducted by adding water into the polymer 1 solution in acetone at 2.0 mg mL −1 because water is a selective solvent for the hydrophilic PDMAEMA block and acetone is the common solvent.…”

“…For preparing the big vesicles that can undergo osmotically induced shape transformation, we synthesized amphiphilic block copolymer poly(N,N-dimethylaminoethyl methacrylate)-block-poly{benzyl methacrylate-co-4-methyl-[7-(methacryloyl)oxy-ethyloxy]coumarin} (PDMAEMA-b-P(BzMA-co-CMA), containing photo-crosslinkable coumarin groups (CMA) in the P(BzMA-co-CMA) block (the random copolymer of BzMA and CMA), by reversible addition-fragmentation chain transfer polymerization according to the procedures reported in our previous work. [14] For polymer 1, the average numbers of the repeat units of PDMAEMA and P(BzMA-co-CMA) blocks were measured by 1 H NMR to be 92 and 478-co-50, respectively; the polydispersity measured by gel permeation chromatography is 1.25 ( Figure S1 Herein, efficient fabrication of polymersomes that have unique and nonequilibrium morphologies is reported. Starting from preparing big polymeric vesicles sized around 2 µm with a flexible but crosslinkable structure, a controllable morphological transformation process from the vesicles via prolate vesicles and the pearl-chain-like structure, which are the two intermediate structures, to vesicle-end-capped tubes is conducted.…”

Mechanochemical reactions within graft copolymeric assemblies: ultrasound-induced multimechanophore activation, arm chain scission, and aggregation morphology/size changes

“…22,[25][26][27] Considerable research efforts have therefore been devoted to the preparation of ultrasound-responsive polymeric assemblies. [28][29][30][31][32][33][34][35][36][37] In the majority of reported cases, the assemblies are constructed via the self-assembly of amphiphilic block copolymers with specific polymeric structures. 21,33 Upon sonication, the reversible impairment of secondary forces or irreversible chemical reactions occurs within these assembly structures.…”

“…[28][29][30][31][32][33][34][35][36][37] In the majority of reported cases, the assemblies are constructed via the self-assembly of amphiphilic block copolymers with specific polymeric structures. 21,33 Upon sonication, the reversible impairment of secondary forces or irreversible chemical reactions occurs within these assembly structures. 28,30,33,34,36 Such systems have illustrated the mechanism behind, and the characteristics of, ultrasound-responsive structures and have successfully been used in drug delivery systems.…”

“…21,33 Upon sonication, the reversible impairment of secondary forces or irreversible chemical reactions occurs within these assembly structures. 28,30,33,34,36 Such systems have illustrated the mechanism behind, and the characteristics of, ultrasound-responsive structures and have successfully been used in drug delivery systems. 21,26,28,29,33 Unfortunately, most reported systems are based on the physical responsive characteristics, and the necessary frequency of the ultrasonic waves is high.…”