“pH-triggered” drug release using shell cross-linked micelles from aqueous RAFT-synthesized PAPMA-b-PNIPAM copolymers

Abstract

A new polymer namely poly (N-(3-aminopropyl) methacrylamide)-b-poly(N-isopropylacrylamide) (PAPMA-b-PNIPAM) was made for pH-triggered drug delivery by means of aqueous reversible addition-fragmentation chain transfer (RAFT) polymerization. PAPMA-b-PNIPAM was hydrophilic at 25 °C, and micelles were formed at 39 °C. The PAPMA chain was crosslinked with terephthaldicarboxaldehyde at pH = 9.0 and shell cross-linking (SCL) micelles were prepared. The sizes of the SCL micelles were 45~65 nm which can be reversible dissociated under acidic conditions. The formation of temperature-responsive SCL micelles and their cleavage behaviours were characterized.