Poly acid PLGA micelles

An example is the fabrication of micelles that are composed of inert hydro-phobic cores with an outer shell of polyNIPAAm, which have shown phase transitions that are slightly above 32°C [125]. This change in the outer shell above the LCST from hydrophilic to hydrophobic results in micelle aggregation, self-reorganization, accelerated drug release, and enhanced interactions with cells. The hydrophobic blocks that are used to form the core of PNI-PAAm-based micelles are methacrylic acid stearoyl ester (MASE), stearoyl chloride (SC) [126], poly(A-butyl methacrylate) (PBMA) [125, 126, 134], polystyrene (PS) [124], and poly(D,L-lactide-co-glycolide) (PLGA) [135, 136]. 

Amphiphilic block copolymers in selective solvents undergo self-assembly into various nanosized morphologies [2,3]. Typical aggregates formed by the block copolymers are polymeric micelles with spherical shapes consisting of a core and a coronal shell. These spherical polymeric micelles are several tens of nanometers across with a narrow size distribution, and they are characterized by their unique core-shell structure, in which a core composed of insoluble blocks is surrounded by a palisade of soluble (hydrophihc) blocks. So far, polymeric micelles intended for biomedical use have been prepared from a variety of amphiphilic block copolymers including PEO-fc-PBLA [51-56], poly(ethylene oxide)-fc-poly(propylene oxide)-fc-poly(ethylene oxide) (PEO-fo-PPO-fo-PEO) (Pluronic) [9], PEO-fo-phosphatidylethanolamine (PEO-fo-PE) [12,13], PEO-fo-PDLLA [40-43], PEO-fc-poly(e-caprolactone) (PEO-fc-PCL) [11], and PEO-fo-poly(lactide-co-glycolic acid) (PEO-fc-PLGA) [57]. 

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