Effect of flow on targeting and penetration of angiopep-decorated nanoparticles in a microfluidic model blood-brain barrier

PLoS One. 2018 Oct 9;13(10):e0205158. doi: 10.1371/journal.pone.0205158. eCollection 2018.

Abstract

The blood-brain barrier (BBB) limits transport of nanoparticles from the circulation to the brain parenchyma. Angiopep-2, a peptide which functions as a brain transport vector, can be coupled to nanoparticles in order to facilitate binding and internalization by brain endothelial cells (ECs), and subsequent BBB penetration. This multi-step process may be affected by blood flow over brain ECs, as flow influences endothelial cell phenotype as well as interactions of nanoparticles with ECs. In the present study a microfluidic BBB model was constructed to evaluate binding and internalization by brain ECs, as well as BBB penetration of Angiopep-2 coupled liposomes (Ang2-Liposomes) in static and flow conditions. Ang2 conjugation to liposomes markedly improved binding relative to unconjugated liposomes. Ang2-Liposomes bound and were internalized efficiently by brain endothelial cells after static incubation or with 1 dyne/cm2 of fluid shear stress (FSS), while binding was reduced at a FSS of 6 dyne/cm2. Penetration of the model microfluidic BBB by Ang2-Liposomes was higher at a FSS of 1 dyne/cm2 and 6 dyne/cm2 than with static incubation. Analysis of barrier function and control experiments for receptor-mediated penetration provided insight into the magnitude of transcellular versus paracellular transport at each tested FSS. Overall, the results demonstrate that flow impacted the binding and BBB penetration of Ang2-functionalized nanoparticles. This highlights the relevance of the local flow environment for in vitro modeling of the performance of nanoparticles functionalized with BBB penetrating ligands.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Blood Flow Velocity
  • Blood-Brain Barrier / metabolism*
  • Capillary Permeability / physiology
  • Cell Line
  • Cellular Microenvironment
  • Drug Delivery Systems
  • Endothelial Cells / metabolism*
  • Liposomes / metabolism*
  • Mice
  • Microfluidics
  • Nanoparticles / metabolism*
  • Peptides / metabolism*
  • Stress, Mechanical

Substances

  • Angiopep-2
  • Liposomes
  • Peptides

Grants and funding

Funding for this study was provided by the National Institutes of Health grants R01EB016102 and R21 NS105837 (TP), www.nih.gov. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.