Poly (sodium 2-(acrylamido)-2-methylpropanesulfonate)-block-poly(ethylene glycol)-block-poly(sodium 2- (acrylamido)-2-methylpropanesulfonate) (PAMPS48-PEG227-PAMPS48) and poly(ethylene glycol)-block-poly(3-(methacryloylamino)propyl) trimethylammonium chloride (PEG47-PMAPTACm, m = 27,53, and 106) with different PMAPTAC chain lengths were prepared via reversible addition-fragmentation chain transfer controlled living radical polymerization using PEG-based macro chain transfer agents. The subscript numbers in abbreviation represent the degree of polymerization of the block. Mixing of aqueous solutions of the oppositely charged anionic triblock copolymer, PAMPS48-PEG227-PAMPS48, and cationic diblock copolymers, PEG47-PMAPTACm led to the spontaneous formation of Polyion Complex (PIC) micelles. The characterization data of NMR, light scattering, ?-potential, and transmission electron microscopic measurements indicated that the PIC flower micelles were formed comprising the segregated PIC core and surrounded hydrophilic linear and loop PEG shell chains. Aggregation number and hydrodynamic radius achieved maximum values when anionic and cationic blockchain lengths of the block copolymers were approximately the same.

Cancers are threats to human’s lives and hard to diagnose and treat. In today’s fights against cancers, it has been shown that traditional treatments cannot meet the requirements. Nanotechnology, as a new and productive tool, has appeared in this world and given new hopes to researchers and patients of cancers. In this article, we highlight the significance of the applications of nanotechnology in the area of cancer therapy，especially in the drug delivery and drug resistance. For example, how to accurately and thoroughly eliminate cancer cells is one of central problems in treatment of cancers, some kind of nanoparticles have been widely used in the drug delivery and drug assistance based on their special properties to solve the problems.