The effects of polymeric nanostructure shape on drug delivery.

Amphiphilic polymeric nanostructures have long been well-recognized as an excellent candidate for drug delivery applications. With the recent advances in the "top-down" and "bottom-up" approaches, development of well-defined polymeric nanostructures of different shapes has been possible. Such a possibility of tailoring the shape of the nanostructures has allowed for the fabrication of model systems with chemically equivalent but topologically different carriers. With these model nanostructures, evaluation of the importance of particle shape in the context of biodistribution, cellular uptake and toxicity has become a major thrust area. Since most of the current polymeric delivery systems are based upon spherical nanostructures, understanding the implications of other shapes will allow for the development of next generation drug delivery vehicles. Herein we will review different approaches to fabricate polymeric nanostructures of various shapes, provide a comprehensive summary on the current understandings of the influence of nanostructures with different shapes on important biological processes in drug delivery, and discuss future perspectives for the development of nanostructures with well-defined shapes for drug delivery.