Vasoactive intestinal peptide amphiphile micelle material properties influence their cell association and internalization

Abstract

Vasoactive intestinal peptide (VIP) is a promising anti-inflammatory peptide therapeutic that is known to induce biological effects by interacting with its cognate receptor (i.e., VPAC) on the surface of antigen presenting cells (APCs). Little is known about how VPAC targeting affects APC behavior for VIP-based drug delivery systems like nano- and microparticles. This is further influenced by the fact that particulate material properties including chemistry, shape, and size are all known to influence APC behavior. In this study, peptide amphiphile micelles (PAMs) were employed as a modifiable platform to study the impact VPAC targeting and physical particle properties have on their association with macrophages. VIP amphiphile micelles (VIPAMs) and their scrambled peptide amphiphile micelle analogs (^SVIPAMs) were fabricated from various chemistries yielding particle batches that were comprised of spheres (10–20 nm in diameter) and/or cylinders of varying lengths (i.e., 20–9000 nm). Micelle surface attachment to and internalization by macrophages were observed using confocal microscopy and their association was characterized by flow cytometry. The enclosed work provides strong evidence that macrophages rapidly bind VPAC specific micelles, and that micelle shape, size, and receptor-specificity all influence macrophage association and internalization. Specifically, a mixture of spherical and short cylindrical VIPAMs were able to achieve the greatest cell association which may correlate to their capacity to fully bind the VPAC receptors available on the surface of macrophages. These results provide the foundation of how nano- and microparticle physical properties and targeting capacity combine to influence their capacity to associate with APCs.