Spatially resolved small-angle X-ray scattering for characterizing mechanoresponsive liposomes using microfluidics
Marzia Buscema1, Hans Deyhle1, Thomas Pfohl1,2
1Biomaterials Science Center, Department of Biomedical Engineering, University of Basel, Gewerbestrasse 14, CH-4123 Basel, Switzerland.
Materials Today. Bio
|March 12, 2020
Summary
Mechanoresponsive liposomes release vasodilators when blood flow changes in atherosclerosis. Gradient forces, not shear stress, trigger structural changes in these liposomes, enabling targeted drug delivery.
Area of Science:
- Biophysics
- Materials Science
- Nanotechnology
Background:
- Atherosclerosis causes blood vessel narrowing, altering blood flow and increasing wall shear stress.
- Specific 1,3-diaminophospholipids (Pad-PC-Pad) liposomes release vasodilators in response to physical triggers.
- The flow-induced structural changes of these mechanoresponsive liposomes were previously unknown.
Purpose of the Study:
- To investigate the purely physical mechanisms behind drug release from mechanoresponsive liposomes under flow conditions.
- To understand the flow-induced structural changes of Pad-PC-Pad liposomes in a microfluidic model of a stenotic blood vessel.
Main Methods:
- Combined microfluidics with spatially resolved small-angle X-ray scattering (SAXS).
- Utilized a microfluidic device mimicking a stenotic artery with a 125 μm constriction.
- Measured local changes in liposome bilayer thickness and size under varying flow rates.
Main Results:
- Liposome shape and bilayer thickness changed near the constriction, with dominant alterations near the outlet.
- At 0.2 μL/s flow rate, liposome bilayer thickness increased by 30% compared to static conditions.
- Increased bilayer thickness correlated with reduced interdigitation of phospholipid amide chains.
Conclusions:
- Gradient forces, rather than wall shear stress, are the primary drivers of structural changes in Pad-PC-Pad liposomes at stenoses.
- The microfluidics-SAXS approach enables the study of mechanoresponsive liposome behavior under flow.
- This research paves the way for designing targeted drug delivery systems for vascular constrictions.
