  The human aorta is a high-risk area for vascular diseases, which are commonly
restored by thoracic endovascular aortic repair. In this paper, we report a
promising shear-activated targeted nanoparticle drug delivery strategy to
assist in the treatment of coarctation of the aorta and aortic aneurysm.
Idealized three-dimensional geometric models of coarctation of the aorta and
aortic aneurysm are designed, respectively. The unique hemodynamic environment
of the diseased aorta is used to improve nanoparticle drug delivery.
Micro-carriers with nanoparticle drugs would be targeting activated to release
nanoparticle drugs by local abnormal shear stress rate (SSR). Coarctation of
the aorta provides a high SSR hemodynamic environment, while the aortic
aneurysm is exposed to low SSR. We propose a method to calculate the SSR
thresholds for the diseased aorta. Results show that the upstream near-wall
area of the diseased location is an ideal injection location for the
micro-carriers, which could be activated by the abnormal SSR. Released
nanoparticle drugs would be successfully targeted delivered to the aortic
diseased wall. Besides, the high diffusivity of the micro-carriers and
nanoparticle drugs has a significant impact on the surface drug concentrations
of the diseased aortic walls, especially for aortic aneurysms. This study
preliminary demonstrates the feasibility of shear-activated targeted
nanoparticle drug delivery in the treatment of aortic diseases and provides a
theoretical basis for developing the drug delivery system and novel therapy.
