Nanometer‐Scaled Hollow Spherical Micelles with Hydrophilic Channels and the Controlled Release of Ibuprofen

Abstract

PS‐b‐PAA spherical micelles with a liquid core and a PAA shell are prepared with the assistance of 1,2‐dichloroethane. During the process of adding a mixture of PNIPAM‐b‐P4VP and PEG‐b‐P4VP, multi‐layered micelles with a mixed corona that consists of both PNIPAM and PEG chains are constructed through the electrostatic interaction and hydrogen bonding between the PAA block and the P4VP block. When heating above the LCST, the PNIPAM chains collapse onto the PAA/P4VP complex layer while the PEG chains still stretch into the solution through the collapsed PNIPAM layer, which leads to the formation of hydrophilic channels around the PEG chains. The ibuprofen encapsulated in the hollow space can diffuse through the channels and its release rate can be controlled by changing the ratio of PEG chains to PNIPAM chains in the corona.

Polymeric Micelles with Tunable Channels

“…Both of the above two kinds of complex micelles with channels have a hydrophobically associated core and are generally prepared by comicellization of two block copolymers with a common hydrophobic block in aqueous solutions. Afterwards, we developed a new type of hollow spherical complex micelles with PEG channels with the aid of dichloroethane 31. An O/W emulsion with an oil phase of dichloroethane and a PAA surface is prepared and followed by deposition of PNIPAM ‐b‐ P4VP and PEG ‐b‐ P4VP through the interaction between poly(acrylic acid) (PAA) and P4VP.…”

“…Curve 1, 2, and 3 are corresponding to micelles with only PEG in the corona but different ratios of 4VP to AA units as 0.7, 1.0, and 1.4, respectively. Curve 4, 5, and 6 are the release profiles of complex micelles with a mixed corona; the weight content of PEG ‐b‐ P4VP in cure 4, 5, and 6 are 30, 50, and 70%, respectively 31…”

Modulating the catalytic activity of Au/micelles by tunable hydrophilic channels

“…PNIPAM 172 -b-P4VP 73 and PEG 114 -b-P4VP 84 were synthesized by the polymerization of 4VP using CH 3 O-PEG 114 -Br (PEG 114 -Br) or PNIPAM-Cl as macro-initiator. The macro-initiator was synthesized according to [26][27][28]. The block copolymers were characterized by 1 H NMR and GPC and the results are listed in Table 1.…”

Self‐Assembly Strategy for the Preparation of Polymer‐Based Nanoparticles for Drug and Gene Delivery

“…At temperatures higher than the LCST, the PNIPAM chains collapsed onto the PAA/P4VP complex layer while the PEG chains still stretched into the solution through the collapsed PNIPAM layer, which could act as the hydrophilic channels for drug release. The drug release rate could be controlled by changing the ratio of PEG chains to PNIPAM chains in the corona 104. Another typical example is self‐assemblies based on the ABC miktoarm star terpolymer PEG( ‐b‐ PMAA) ‐b‐ PDEA consisting of PEG, poly(methacrylic acid (PMAA)) and poly[2‐(diethylamino)ethyl methacrylate (PDEA)] arms.…”