Folic acid and rhodamine labelled pH responsive hyperbranched polymers: Synthesis, characterization and cell uptake studies

Abstract

Here, we report the synthesis of novel folated and fluorescent labelled pH responsive hyperbranched polymers (HBPs) via reversible addition fragmentation chain-transfer (RAFT) co-polymerization of 2-propyl acrylic acid (PAA), 2-(dimethylamino) ethyl methacrylate (DMAEMA) and disulfide diacrylate (DSDA) using 4-cyano-4-(((dodecylthio)carbonothioyl)thio)pentanoic acid (CDCTPA) as RAFT agent and post functionalization via bioconjugation techniques. The resultant HBPs were characterized by Nuclear Magnetic Resonance Spectroscopy (NMR) and Size Exclusion Chromatography (SEC). Dynamic Light Scattering (DLS) technique was used to measure the size changes of HPBs in solutions at different pH values to demonstrate pH responsiveness of the polymers. The cell uptake evaluations on these folated and fluorescent labelled HBPs were carried out using HeLa cell line and confirmed by confocal images. The results show that we have successfully synthesized the desired multifunctional hyperbranched poly (PAA-co-DMAEMA-co-DSDA) with a pH responsive characteristic and the potentials for use as a drug delivery vehicle.