Quantitation of nanoparticle accumulation in flow using optimized microfluidic chambers

Abstract

Background: The vascular cell adhesion molecule-1 (VCAM-1) targeting peptide sequence, VHPKQHR, is a promising moiety for targeting atherosclerosis through incorporation into nanoparticles such as dendrimers and liposomes.

Purpose: We aim to develop VCAM-1-targeted nanoparticles that effectively accumulate on the endothelium under shear conditions and to develop robust microfluidic chambers able to house sufficient cells for flow cytometric measurements.

Methods: Carboxyfluorescein-labeled monomeric VHP-peptide, tetrameric VHP-dendrimers (bisbidentate or radial architecture, with or without N-terminal acetylation) and VHP-peptide liposomes were prepared. Human umbilical vein endothelial cells were treated with nanoparticles under 0 or 2.9 dyne/cm² shear, and particle binding was quantified. Flow chambers cured at various temperatures, with or without glass backings were fabricated, characterized for deformation and applied in experiments.

Results: Although liposomes accumulated with highest efficiency, dendrimers also demonstrated specific binding. N-terminal acetylation significantly reduced dendrimer binding, and despite shorter movement range, bisbidentate dendrimers outperformed radial dendrimers, suggesting multiple epitope presence within its estimated arm-span of 57 Å. Under shear, while liposome binding increased 300%, dendrimer binding to cells decreased 65%. Through higher temperature curing and glass backing insertion, polydimethylsiloxane flow chambers maintaining rectangular cross-section with aspect-ratio as low as 1:111 were achieved.

Conclusion: Optimized dendrimers and liposomal nanocarriers specifically accumulated onto cells within microfluidic chambers.

• Atherosclerosis
• dendrimers
• in vitro model
• liposomes
• peptide
• targeted drug delivery