Self‐Assembled Micellar Aggregates From Star‐Shaped Copolymers Decorated With Cholesterol

ABSTRACT In this work, we synthesized star‐shaped triblock copolymers based on poly(ε‐caprolactone) (PCL), poly(2‐hydroxyethyl acrylate) (PHEA), and poly( N ‐acryloyl D‐glucosamine) (PAGA). PCL macro‐RAFT agent was chain extended with 2‐hydroxyethyl acrylate (HEA) via RAFT polymerization, followed by N ‐acryloyl D‐glucosamine (AGA) to achieve the triblock. The length of the PHEA block was varied from DP = 2–59 per arm. The self‐assembly behavior of PCL‐ b ‐PHEA diblock copolymer was studied in deionized water. By AFM, large semi‐spherical micellar aggregates with a diameter of approximately 318–238 nm were observed. Some of these copolymers were decorated with cholesterol. PHEA block was mainly incorporated as a template to anchor cholesterol (Chol) and provide amphiphilic properties to the diblock, facilitating efficient extension of polymerization of AGA. The content of cholesterol conjugated in the PHEA block was 2.5%. It was found that the micellar aggregates prepared with the cholesterol‐decorated diblock practically tripled their diameter. By introducing the PAGA block, the micellar aggregates reduced their size (111–136 nm in diameter), improved colloidal stability, and turned into a material with unique characteristics that can be used as nanocarriers of therapeutic agents.