Programmable Shape‐Shifting Micelles

Abstract

Getting in shape: DNA‐brush copolymer amphiphiles assemble into micelles with morphologies determined by selective interactions that allow manipulation of the magnitude of steric and electrostatic repulsions in the micelle shells. Cylinder‐to‐sphere phase transitions occur when an input DNA sequence is added to the micelles (see picture).

The Effect of Hydrophile Topology in RAFT‐Mediated Polymerization‐Induced Self‐Assembly

“…In this case, P depends on the relative volume fractions of the hydrophilic and hydrophobic blocks,and the interfacial energy associated with the di-block junction. Va rying the relative volume fractions of each block (by altering their molar masses) usually dictates the final morphology.T his is the result of the inherent molecular curvature and its influence on the packing of copolymer chains.[4b]Among the large number of studies dedicated to selfassembly of amphiphilic block copolymers,o nly af ew focus on the effect of hydrophile topology on the final morphologies.Inparallel with the first report by Eisenberg, [3a] van Hest et al showed that aggregation in water of preformed amphiphilic block copolymers based on ahydrophobic polystyrene block and hydrophilic polypropyleneimine dendrons was governed by generation of the latter.[6] Thef inding enabled consistent prediction of structures based on the packing parameter.Synthesizing DNA-brush copolymer amphiphiles, Chien et al reported that micelle morphologies could be governed by selective cleavage in the DNAs hell, [7] resulting in manipulation of the magnitude of steric and electrostatic repulsions within the shell, and thus of the packing parameter. Very recently,M artinez et al synthesized polystyrene-bpolyisoprene (PS-b-PI) block copolymers using anionic polymerization.…”

Nucleic acid amphiphiles: synthesis and self-assembled nanostructures

“…This lengthening restored the initial structural parameters, producing spherical aggregates again. 34 Such reversible techniques for structural manipulation should eventually produce potential applications of AONs in the biomedical field with possibly the same impact as peptide amphiphiles. 47 …”

“…Recently, Gianneschi et al reported an analogous brush block copolymer (15), in which one block contained carboxylic acid in each repeating unit, which could be conjugated to amino-modified DNA, while in the other block methylbenzene was incorporated as a hydrophobic functionality. 34 Here, amino-modified DNA on solid-supports was reacted with the diblock copolymers to realize an amide bond between the DNA and the polymer backbone.…”

Morphological transition triggered by mannose conjugation to a cyclic hexapeptide

“…6b A recent report by Gianneschi and coworkers demonstrated the crucial role of hydrophobic to hydrophilic balance in inducing morphological changes from micellar to cylindrical shape. 23 In our recent report, we had also shown that conjugation of mannose to diphenylalanine dipeptide exerted morphological changes depending upon number of mannose residues due to increased hydrophilic character. 11h Also we observed in the crystal structure that the presence of the hydroxyl group of Ser side-chain is critical in stabilization of stacking of cyclic peptide 6.…”