In this study, a cholesterol functionalized aliphatic cyclic carbonate monomer, 2-(5-methyl-2-oxo-1,3-dioxane-5-carboxyloyloxy)ethyl carbamate (MTC-Chol) was synthesized. The organo-catalytic ring opening polymerization of MTC-Chol was accomplished by using N-(3,5-trifuluoromethyl)phenyl-N′-cyclohexylthiourea (TU) in combinations with bases such as 1,8 diazabicyclo[5.4.0]undec-7-ene (DBU) and (-) sparteine and kinetics of polymerization was monitored. By using mPEG-OH as the macro-initiator, well-defined amphiphilic diblock copolymers mPEG113-b-P(MTC-Chol)n (n = 4 and 11) were synthesized. Under aqueous conditions, these block copolymers self-assembled to form unique nanostructures. Disk-like micelles and stacked disk morphology were observed for mPEG113-b-P(MTC-Chol)4 and mPEG113-b-P(MTC-Chol)11, respectively by transmission electron microscopy (TEM). Small angle neutron scattering support the disk-like morphology and estimate the block copolymer micelle aggregation number in the dispersed solution. The hydrophobic nature of the cholesterol-containing block provides a versatile self-assembly handle to form complex nanostructures using biodegradable and biocompatible polymers that are platforms for novel drug delivery vehicles.
Pub Type: Journals
polymer, block copolymer, neutron scattering, drug delivery, micelle, structure, cholesterol, PEG, SANS