pH- and thermo-multi-responsive fluorescent micelles from block copolymers via reversible addition fragmentation chain transfer (RAFT) polymerization

✍ Scribed by Natthaporn Suchao-in; Suwabun Chirachanchai; Sébastien Perrier

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 530 KB
• Volume: 50
• Category: Article
• ISSN: 0032-3861
• DOI: 10.1016/j.polymer.2009.06.047

✦ Synopsis

Well-defined pH-and thermo-multi-responsive fluorescent micelles based on the self-assembly of diblock copolymers poly[(N-isopropyl-acrylamide-co-N-vinylcarbazole)-b-2-(dimethylamino)ethyl acrylate], (PNIPAAM-co-PNVC)-b-PDMAEA, are described. The diblock copolymers are prepared via the reversible addition fragmentation chain transfer (RAFT) copolymerization of N-isopropyl-acrylamide (NIPAAM) and N-vinylcarbazole (NVC) followed by chain extension in presence of 2-(dimethylamino)ethyl acrylate) (DMAEA). The micelles are formed in aqueous solutions in a wide range of temperature (25-60 C), and their sizes increase from 40 to 65 nm when varying pH from basic to acidic. The cross-linking of the PDMAEA-containing shell with 1,2-bis(2-iodoethoxy)ethane (BIEE) results in spherical soft nanoparticles which size is increased by 20-25% when compared to the micelles. The presence of NVC in concentrations as low as 4% in the core of the micelles allow the nanoparticles to be tagged by fluorescence, making them well suited for therapeutic applications.