Figure 3.

Nanoparticle shape influences the biological response both in vitro and in vivo for drug and gene delivery applications. (A) Nanoparticle shape is influenced by the crowdedness of the PEG layer on the surface of polymer/DNA micelles. Dense PEG layer leads to the formation of longer rod shapes that, upon systemic administration via tail vein injection, leads to extended circulation compared to shorter, rod shaped micelles;¹²² (reprinted with permission, ©2013 American Chemical Society) (B) Greater tumor penetration is observed following i.v. injection of spherical and rod-shaped silica-quantum dot nanoparticles;¹³⁷ (reprinted with permission, ©2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) (C) Scanning electron microscopy images of polystyrene nanospheres, nanorods, and nanodisks, as well as fluorescent microscopy images of in vitro cellular uptake of shaped nanoparticles (green) in BT-474 breast cancer cells (blue) comparing uncoated and antibody (trastuzumab)-coated particles. Graph shows that trastuzumab coating enhancement is greatest for nanorods, followed by nanodisks and nanospheres in both BT-474 cells (white bars) and SK-BR-3 cells (dashed bars). No enhancement was observed for any shape in MDA-MB-231 cells (black bars).³⁵