Linear-dendritic block copolymer for drug and gene delivery

Dendrimers as a new class of polymeric materials have a highly ordered branched structure, exact molecular weight, multivalency and available internal cavities, which make them extensively used in biology and drug-delivery. Concurrent with the development of dendrimers, much more attention is drawn to a novel block copolymer which combines linear chains with dendritic macromolecules, the linear-dendritic block copolymer (LDBC). Because of the different solubility of the contrasting regions, the amphiphilic LDBCs could self-assemble to form aggregates with special core-shell structures which exhibit excellent properties different from traditional micelles, such as lower critical micelle concentration, prolonged circulation in the bloodstream, better biocompatibility, and lower toxicity. The present review briefly describes the type of LDBC, the self-assembly behavior in solution, and the application in delivery system including the application as drug carriers and gene vectors. The interactions between block copolymers and drugs are also summarized to better understand the release mechanism of drugs from the linear-dendritic block copolymers.