Shape Induced Inhibition of Phagocytosis of Polymer Particles

Top Cited Papers
Publisher Website
Google Scholar
Abstract
Purpose To determine if particle shape can be engineered to inhibit phagocytosis of drug delivery particles by macrophages, which can be a significant barrier to successful therapeutic delivery. Methods Non-spherical polystyrene particles were fabricated by stretching spherical particles embedded in a polymer film. A rat alveolar macrophage cell line was used as model macrophages. Phagocytosis of particles was assessed using time-lapse video microscopy and fluorescence microscopy. Results We fabricated worm-like particles with very high aspect ratios (>20). This shape exhibits negligible phagocytosis compared to conventional spherical particles of equal volume. Reduced phagocytosis is a result of decreasing high curvature regions of the particle to two single points, the ends of the worm-like particles. Internalization is possible only at these points, while attachment anywhere along the length of the particles inhibits internalization due to the low curvature. Conclusions Shape-induced inhibition of phagocytosis of drug delivery particles is possible by minimizing the size-normalized curvature of particles. We have created a high aspect ratio shape that exhibits negligible uptake by macrophages.