Glucan Particles as Carriers of Nanoparticles for Macrophage-Targeted Delivery

Glucan particles (GP) are 2-4 mu m hollow and porous microspheres derived from Saccharomyces cerevisiae (Baker's yeast) that provide an efficient system for encapsulation, protection, and oral or systemic macrophage-targeted delivery of macromolecules, such as DNA, siRNA and proteins using either a polyplex or layer-by-layer (LbL) synthesis methods. We have recently extended the application of GPs to the delivery of nanoparticles (NP) that are encapsulated within the hollow cavity of GPs or bound to the outer surface of chemically derivatized GPs (Soto, et al. J. Drug Delivery, 2012, Article ID 143524). GP mediated delivery of nanoparticles provides the advantages of (1) encapsulation of materials that are difficult to prepare in situ within the glucan particles, such as nanomaterials composed of water-insoluble components, (2) beta 1,3-D-glucan receptor-targeted delivery of nanoparticles to phagocytic innate immune cells, (3) small molecule loaded nanoparticles for small drug molecule delivery, and (4) targeted delivery of nanoparticles with an intrinsic property, such as magnetic or gold nanoparticles, thus increasing the versatility of the GPs for theranostic applications. Examples of nanoparticles that have been formulated with GPs include magnetic iron oxide nanoparticles, gold nanoparticles, quantum dots and adeno-associated virus (AAV).