title: The association of silicon microparticles with endothelial cells in drug delivery to the vasculature.
abstract: Endothelial targeting is an approach evolving for drug delivery to the vasculature of pathological lesions. Nano-porous silicon-based multi-functional particles are of particular interest, since they can be manufactured in essentially any size and shape, employing methods of photolithography, to optimize their ability to localize on target endothelia. In this study we tested the impact of surface charge, serum opsonization, and inflammation on the ability of vascular endothelial cells to associate with nano-porous silicon microparticles. Vascular endothelial cells were capable of rapidly internalizing both positive and negative silicon microparticles by an actin-dependent mechanism involving both phagocytosis and macropinocytosis. However, following serum opsonization, internalization was selective for APTES (originally positive) modified microparticles, despite the finding that all opsonized microparticles had a net negative charge. Conversely, macrophages displayed a preference for internalization of serum opsonized oxidized (originally negative) microparticles, supporting the choice of positive microparticles for endothelial targeting. The internalization of opsonized microparticles by endothelial cells was further enhanced by the presence of inflammatory cytokines. These findings suggest that it may be possible to bioengineer silicon microparticles to favor opsonization with proteins that enhance uptake by endothelial cells, without a concurrent enhanced uptake by macrophages.
authors.affiliation: Brown Institute of Molecular Medicine, University of Texas Health Science Center, Nanomedicine Division, 1825 Pressler, Suite 537, Houston, TX 77030, USA. rita.serda@uth.tmc.edu
authors.forename: Rita E
authors.initials: RE
authors.lastname: Serda
authors.forename: Jianhua
authors.initials: J
authors.lastname: Gu
authors.forename: Rohan C
authors.initials: RC
authors.lastname: Bhavane
authors.forename: XueWu
authors.initials: X
authors.lastname: Liu
authors.forename: Ciro
authors.initials: C
authors.lastname: Chiappini
authors.forename: Paolo
authors.initials: P
authors.lastname: Decuzzi
authors.forename: Mauro
authors.initials: M
authors.lastname: Ferrari
mesh_terms: D002478:Cells, Cultured; D017077:Culture Media, Conditioned; D003571:Cytochalasin B / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology; D016503:Drug Delivery Systems; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D010316:Particle Size; D010587:Phagocytosis; D012825:Silicon / Q000737:chemistry*; D014680:Veins / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D017077:Culture Media, Conditioned; D016207:Cytokines; D003571:Cytochalasin B; D012825:Silicon