Core-Polymerized Reactive Micelles from Heterotelechelic Amphiphilic Block Copolymers

Abstract

Amphiphilic poly(ethylene glycol)-b-polylactide (PEG/PLA) copolymers with an aldehyde group at one end and a methacryloyl group at the other chain end were synthesized by anionic polymerization. The efficiencies of the functionalization at both ends were almost quantitative. The amphiphilic block copolymers formed micelles in aqueous media. Acetal groups on the micelle surface were quantitatively converted to aldehyde groups by an acid treatment. The end methacryloyl group located in the core of the micelle was polymerized effectively to form core−shell-type nanoparticles having reactive aldehyde groups on the surface. The size of the reactive nanoparticle was 20−30 nm which was constant with temperatures up to 60 °C. The stability of the micelle was also confirmed by a sodium dodecyl sulfate (SDS) treatment. When SDS was added to the nanosphere solution to 20 mg/mL, the particle was not collapsed. The particle was stable enough even in organic solvents. This functionalized micelle having high stability is not only expected to have wide utilities in biomedical applications (including drug delivery, diagnosis, and surface modification through the coupling of bioactive substances) but also to be of great interest as a novel supramolecular architecture.

Synthesis and Characterization of Biodegradable Amphiphilic Star and Y-Shaped Block Copolymers as Potential Carriers for Vinorelbine

“…Star-shaped block copolymers with a core consisting of hydrophobic inner branches and multiple hydrophilic poly(ethylene glycol) (PEG) tails have been synthesized in the range of 3 to 32 by Wang et al [7,8], Zheng et al [9] and some other groups [10][11][12][13][14][15][16]. The unimers with arm numbers of 16 or 32 have shown the high stability, drug delivery efficacy and physicochemical properties compared to unimers with a smaller arm number.…”

Boron neutron capture therapy assisted by boron-conjugated nanoparticles

“…58 To prepare the CL micelles, both (VB) 2 -carborane and azobisisobutyronitrile are encapsulated into acetal-PEG-b-PLA-MA micelles, and the core of the micelles were thermally polymerized (60 1C for 24 h), as in our previous report. 49 The average diameter and size distribution of the CL micelles (85.3 nm, m 2 /G 2 ¼ 0.171) were similar to those of the noncrosslinked micelles (NCL micelles) (81.1 nm, m 2 /G 2 ¼ 0.158), suggesting that the core polymerization process does not influence the average diameter or size distribution of the micelles. The loading contents of the (VB) 2 -carborane in the NCL and CL micelles were determined to be 1.0 wt% (loading efficiency: 3.2%) and 0.9 wt% (loading efficiency: 3.1%), respectively.…”

“…[45][46][47][48] We have also previously reported the preparation of core-polymerized PEG-b-PLA micelles that possess a methacryloyl group at the PLA chain end through radical polymerization. 49,50 Eventually, the core-polymerized micelles exhibited high dispersibility (even after lyophilization), as well as high stability against dilution, temperature change and sodium dodecyl sulfate solution. Indeed, these above-mentioned approaches (polymerized and crosslinked micelles) are critical to the formulation of micelles that are resistant to the loss of micelle integrity.…”

Nanomedicine in the diagnosis and therapy of neurodegenerative disorders

“…Examples include amphiphilic scorpion-like block copolymers with low critical micelle concentration (CMC) [151] as well as various types of unimolecular micelles based on amphiphilic star-like macromolecules with covalently bound hydrophobic cores [151,154,232,233]. Core-polymerization was employed to stabilize micelles of heterotelechelic amphiphilic block copolymers containing polymerizable groups at the ends of hydrophobic blocks [234]. Wooley et al have developed cage-like nanostructures on the base of polymeric micelles with hydrophobic core and cross-linked anionic shell [155,235,236].…”