Polymeric Micelles with Tunable Channels

Abstract

This article describes a novel type of polymeric micelles with tunable channels (PMTC), which are usually composed of a common core and a mixed shell of two different kinds of polymer chains with at least one of them being stimuli-responsive. Phase separation of the mixed shell upon stimuli results in channels between the micelle core and the outer milieu for controlling mass exchange. Channel-modulated drug release and catalysis based on PMTC are discussed. The PMTC have peculiar merits including facile manipulation of drug release rate and catalytic velocity, remarkable restraint of burst drug release, and efficient prevention of degradation of the micelle core due to their unique structure. Finally, prospects and challenges of PMTC are reviewed.

Nanostructures and Nanostructured Networks for Smart Drug Delivery

“…The protein channels can be inserted in the micelle shell [176] or can be artificially created using copolymers with the same hydrophobic core but possessing different hydrophilic blocks [177]. In the second case, the copolymers render nanostructured shells that underwent phase separation phenomena when the stimulus is applied.…”

“…The phase separation of the components of the shell results in the opening of pores through which the drug can be released (Figure 18.9) [178]. Temperature-, pH-, or ionic strength-responsive channels are under evaluation for obtaining micelles with switchable drug release [177]. …”

A Multifunctional Nanocarrier Based on Nanogated Mesoporous Silica for Enhanced Tumor‐Specific Uptake and Intracellular Delivery

“…[5] A protective poly(ethylene glycol) (PEG) coating, which prevents nonspecific interaction and stimulation to the immune system, is often employed for prolonged circulation of drug carriers in the blood. [6] Yet recent studies suggest that the very presence of PEG can also limit the interaction between the carriers and the target cells and thus inhibit effective cellular uptake of the loaded drugs. [7,8] In order to enhance the bioavailability of the therapeutic molecules, intelligent carrier systems with low-pH triggered ability are highly desired, since nanoparticles with suitable sizes are mainly taken up by cells via endocytosis [9] A multifunctional drug delivery system based on MCM-41-type mesoporous silica nanoparticles is described that behaves as if nanogates were covalently attached to the outlets of the mesopores through a highly acid-sensitive benzoic-imine linker.…”

Micelas poliméricas para encapsulación, vectorización y cesión de fármacos

“…En esta línea se están evaluando las posibilidades que ofrece el desarrollo de micelas poliméricas con coronas que imiten la estructura de las membranas celulares y, en particular, su capacidad para regular la transferencia de sustancias a través de canales en los que participan proteínas transmembrana. Se ha ensayado ya la inserción de proteínas canal naturales en la corona micelar [144] y también la formación de mímicos artificiales obtenidos a partir de copolímeros que comparten el mismo bloque hidrofóbico pero presentan diferentes bloques hidrofílicos (Figura 5.11) [145]. Estos últimos copolímeros dan lugar a coronas que experimentan fenómenos de 2 1 2 separación de fases cuando se aplica el estímulo.…”

“…La separación de fase genera poros a través de los que el fármaco puede abandonar la micela [146]. Se cuenta ya con prototipos de micelas con canales sensibles a temperatura, pH y fuerza iónica capaces de modular los perfiles de cesión [145].…”