Electrostatic Self-assemble and Nanomedicine

Electrostatic self-assemble (ESA), which based on the alternating physisorption of oppositely charged polyelectrolyte, appears to be a promising method in preparing nanolayer films of biopolymers and controlling the structures and properties in nanoscale. It provides great potential in surface design of nanolayer for bioactive coordinated coating for biomedical device, drug delivery systems and novel gene delivery systems. Although biomedical device developments have increased the quality and life expectancy of patients, the recognition of a foreign material by living organism is still a problem, as it often leads to a serial of adverse reactions, such as thrombus formation and complement activation, etc. The new strategies in this regard aim at surface tailoring of biomaterials in nanoscale to present different biologically activity. Self-assembling of polymers has been increasingly explored for the preparation of well-defined surfaces and interfaces in recent years [1]. Electrostatic self-assemble (ESA), which based on the alternating physisorption of oppositely charged polyelectrolyte, appears to be a promising method in preparing multilayer films of biopolymers [2]. The buildup of such layer is easy and the method can be used whatever the shape of the solid. The procedure may be carried out not only with linear polyions and boladiions, but also with DNA, proteins, virus, ceramics, and charged nanoparticles. Successful protein/polyion multilayer assembly provides new possibilities in the line of efforts to create a method of organizing proteins in layers and to build up such layers following `molecular architecture' plans [3]. The method was extended to build up protein superlattices, i.e.