Degradable PH And Redox Dual Redponsive Nanoparticles For Efficient Covalent Drug Delivery

RAFT polymerization is a kind of living polymerization.It don't need high temperature and can control the molecular weights.What's more,its distribution is narrow Polymer has good biocompatibility and has been widely used in biological study such as drug conjugates.There are two main strategies to improve the solubility of drugs:one strategy involves physically encapsulating the drug into the hydrophobic cavities of drug delivery systems.The other strategy involves conjugating drug molecules to other materials such as polymers by covalent bonds.Examples of successful therapies using macromolecular prodrugs to which the drug is linked via covalent bonds have been reported,however,there are safety concerns which renders them disfavourable for clincal applications.Therefore it is essential to reassess this class of drugs by designing compounds that combine covalent linking with reducible linkers.Herein,we use copolymer encapsulating fluorescence drug to study the drug release,with the same time,the hydrophobic drug paclitaxel was modified into a polymerizable monomer and subsequently copolymerized with pH-sensitive monomers and redox sensitive disulfide-based cyclic monomers.The resulting diblock copolymer can self-assemble into vesicles incorporating the hydrophobic drug PTX into the vesicle walls.When decreasing the pH value,the size of the vesicular drug container varied with the change of hydrophobicity-hydrophobicity balance.Treatment with reducing agents mediated the disassembly of the aggregates facilating the release of the drug moeity Furthermore,in vitro cell experiments showed that the nanoparticles exhibited cytotoxicity indicating it has potential as a drug delivery system for anti-cancer treatment.