Synthesis Of Amphiphilic Block Copolymers With Cholesterol And Vitamin C

Brain-targeted Polymeric core/shell nanoparticles have recently emerged as promising carriers for drug delivery in the therapies of brain diseases, because of the ability of crossing the blood brain barrier (BBB) and delivering drugs to a specific sites in the central nervous system (CNS). In this paper, a novel brain multi-targeted vector of drug which bearing cholesterol and ascorbic acid was designed and synthesized. The transport vector effectively protects the enclosed bioactive compounds and enables them to exhibit prolonged activity in the systemic circulation by avoiding the scavenging of the reticuloendothelial systems (RES) via the glucose transporter GLUT1 or Na+-dependent ascorbate transporter SVCT2.Once the nanoparticles trapped inside the brain, it can be positive uptaked into the cell immediately which prevent pumped back into the blood stream by effective efflux pumps, as the cholesterol has a high thermodynamic affinity toward cell membranes and nucleus. To the best of our knowledge, there are few reports on new biomaterials which have such bio-functions. In this work, the free-radical polymerization, controlled radical polymerization including atom transfer radical polymerization (ATRP), reversible addition fragmentation and transfer (RAFT) polymerization technique was chosen for its tolerance to a wide range of monomers and functional groups. Main-chain and side-chains polymer containing cholesterol were synthesized and self-assembly behavior were also investigated. The main work as follow,(1). A series of acrylic monomer containing cholesterol including cholesteryl (diethylene glycol) acrylate were synthesized.(2). Dithiobenzoate RAFT agents and ATRP initiator molecules containing cholesterol were synthesized.(3). The block polymer using ATRP and RAFT polymerization technique was synthesized, and polymerization conditions including temperature, initiator type, solvent, monomer concentration and dynamic research were investigated.(4). ATRP homo-polymer were synthesized, and using the exchange resins to remove coppers from the polymer.(5). vary kind of parameters for polymer hydrogenation was studied. (6). Self-assembly behaviors were investigated using UV, dynamic light scattering, transmission electron microscopy, fluorescent. The results show that the amphiphilic polymers have good self-assembly behavior whose particle size is about 200 nm, and Maximum package efficiency of 58.8%.