Exploring the Impact of Hemodynamic and Hemorheology in the Design of Carrier for Vascular-Targeted Drug Delivery in Atherosclerosis.

Recently, vascular targeting drug carriers (VTCs) have become one of the most distinguished aspects in pharmaceutical engineering.In order to sustain the ability of localized drug release over time, a carrier must survive through the circulation and be retained at a specific site.Therefore, a multitude of strategies have to be considered to achieve an optimal performing VTC design. Herein, the presented studies aim to elucidate the effect of VTC physical and material properties and the characteristics in prescribing the efficiency of VTCs to marginate to the vascular wall in atherosclerosis via in vitro flow assays and a mouse model atherosclerosis. In the first study, we explore the impact of VTC shapes on their functionality in targeting atherosclerosis and found that microrods were more effective at adhering to mouse aortas than micro and nanospheres, while nanorods particles displayed the same minimal levels as nanospheres due to poor localization to the vessel wall. We also found that targeted microparticles were retained at high levels in the lungs,likely due to molecular interaction with the pulmonary endothelium. In the second study, we explore how particle size, along with hemodynamics and hemorheology affect the adhesion of VTCs in a microfluidic assays. Microspheres were found to exhibit disproportionately higher vascular wall adhesion than nanospheres in all hemodynamic conditions, due to the higher ability to localize to the wall. Moreover, we also investigate the role of hemorheology(RBC’s dimension) in dictating the binding efficiency of spherical VTCs. Our results suggest that the ratio of RBCs size to the carrier size dictate the particle binding. Finally, we study the potential role of plasma proteins and material types which affect the adhesion of VTCs. The results show that the plasma proteins in different species have different effects on particle binding. This study offers the first evaluation of plasma proteins in different animal species to determine how they affect VTCs. In conclusion,we address the crucial factors of hemodynamics, hemorheology and plasma protein to VTC design. This important for many research fields, particularly in cardiovascular diseases as these parameters can be used to improve drug carrier performance.PhDBiomedical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111579/1/katanamd_1.pd

Surface modification of gold nanoparticles with neuron-targeted exosome for enhanced blood–brain barrier penetration

Gold nanoparticles (AuNPs) have been extensively used as nanomaterials for theranostic applications due to their multifunctional characteristics in therapeutics, imaging, and surface modification. In this study, the unique functionalities of exosome-derived membranes were combined with synthetic AuNPs for targeted delivery to brain cells. Here, we report the surface modification of AuNPs with brain-targeted exosomes derived from genetically engineered mammalian cells by using the mechanical method or extrusion to create these novel nanomaterials. The unique targeting properties of the AuNPs after fabrication with the brain-targeted exosomes was demonstrated by their binding to brain cells under laminar flow conditions as well as their enhanced transport across the blood brain barrier. In a further demonstration of their ability to target brain cells, in vivo bioluminescence imaging revealed that targeted-exosome coated AuNPs accumulated in the mouse brain after intravenous injection. The surface modification of synthetic AuNPs with the brain-targeted exosome demonstrated in this work represents a highly novel and effective strategy to provide efficient brain targeting and shows promise for the future in using modified AuNPs to penetrate the brain

Margination Propensity of Vascular-Targeted Spheres from Blood Flow in a Microfluidic Model of Human Microvessels

Many variants of vascular-targeted carriers (VTCs) have been investigated for therapeutic intervention in several human diseases. However, in order to optimize the functionality of VTC in vivo, carriers’ physical properties, such as size and shape, are important considerations for a VTC design that evades the reticuloendothelial system (RES) and successfully interacts with the targeted vessel wall. Nonetheless, little evidence has been presented on the role of size in VTC’s interactions with the vascular wall, particularly in the microcirculation. Thus, in this work, we explore how particle size, along with hemodynamics (blood shear rate and vessel size) and hemorheology (blood hematocrit) affect the capacity for spheres to marginate (localize and adhere) to inflamed endothelium in a microfluidic model of human microvessels. Microspheres, particularly the 2 μm spheres, were found to show disproportionately higher margination than nanospheres in all hemodynamic conditions evaluated due to the poor ability of the latter to localize to the wall region from midstream. This work represents the first evidence that nanospheres may not exhibit “near wall excess” in microvessels, e.g., arterioles and venules, and therefore may not be suitable for imaging and drug delivery applications in cancer and other diseases affecting microvessels

Differential Impact of Plasma Proteins on the Adhesion Efficiency of Vascular-Targeted Carriers (VTCs) in Blood of Common Laboratory Animals

Vascular-targeted carrier (VTC) interaction with human plasma is known to reduce targeted adhesion efficiency in vitro. However, the role of plasma proteins on the adhesion efficiency of VTCs in laboratory animals remains unknown. Here, in vitro blood flow assays are used to explore the effects of plasma from mouse, rabbit, and porcine on VTC adhesion. Porcine blood exhibited a strong negative plasma effect on VTC adhesion while no significant plasma effect was found with rabbit and mouse blood. A brush density poly­(ethylene glycol) (PEG) on VTCs was effective at improving adhesion of microsized, but not nanosized, VTCs in porcine blood. Overall, the results suggest that porcine models, as opposed to mouse, can serve as better models in preclinical research for predicting the in vivo functionality of VTCs for use in humans. These considerations hold great importance for the design of various pharmaceutical products and development of reliable drug delivery systems

Plasma protein corona modulates the vascular wall interaction of drug carriers in a material and donor specific manner.

The nanoscale plasma protein interaction with intravenously injected particulate carrier systems is known to modulate their organ distribution and clearance from the bloodstream. However, the role of this plasma protein interaction in prescribing the adhesion of carriers to the vascular wall remains relatively unknown. Here, we show that the adhesion of vascular-targeted poly(lactide-co-glycolic-acid) (PLGA) spheres to endothelial cells is significantly inhibited in human blood flow, with up to 90% reduction in adhesion observed relative to adhesion in simple buffer flow, depending on the particle size and the magnitude and pattern of blood flow. This reduced PLGA adhesion in blood flow is linked to the adsorption of certain high molecular weight plasma proteins on PLGA and is donor specific, where large reductions in particle adhesion in blood flow (>80% relative to buffer) is seen with ∼60% of unique donor bloods while others exhibit moderate to no reductions. The depletion of high molecular weight immunoglobulins from plasma is shown to successfully restore PLGA vascular wall adhesion. The observed plasma protein effect on PLGA is likely due to material characteristics since the effect is not replicated with polystyrene or silica spheres. These particles effectively adhere to the endothelium at a higher level in blood over buffer flow. Overall, understanding how distinct plasma proteins modulate the vascular wall interaction of vascular-targeted carriers of different material characteristics would allow for the design of highly functional delivery vehicles for the treatment of many serious human diseases

Immersion Vaccination by a Biomimetic-Mucoadhesive Nanovaccine Induces Humoral Immune Response of Red Tilapia (Oreochromis sp.) against Flavobacterium columnare Challenge

Immersion vaccination with a biomimetic mucoadhesive nanovaccine has been shown to induce a strong mucosal immune response against columnaris disease, a serious bacterial disease in farmed red tilapia caused by Flavobacterium columnare. However, the induction of a systemic immune response by the vaccine is yet to be investigated. Here, we examine if a specific humoral immune response is stimulated in tilapia by a biomimetic-mucoadhesive nanovaccine against Flavobacterium columnare using an indirect-enzyme-linked immunosorbent assay (ELISA), serum bactericidal activity (SBA) and the expression of immune-related genes within the head-kidney and spleen, together with assessing the relative percent survival of vaccinated fish after experimentally infecting them with F. columnare. The anti-IgM antibody titer of fish at 14 and 21 days post-vaccination was significantly higher in chitosan complex nanoemulsion (CS-NE) vaccinated fish compared to fish vaccinated with the formalin-killed vaccine or control fish, supporting the serum bactericidal activity results at these time points. The cumulative mortality of the unvaccinated control fish was 87% after challenging fish with the pathogen, while the cumulative mortality of the CS-NE vaccinated group was 24%, which was significantly lower than the formalin-killed vaccinated and control fish. There was a significant upregulation of IgM, IgT, TNF α, and IL1-β genes in the spleen and kidney of vaccinated fish. Significant upregulation of IgM and IgT genes was observed in the spleen of CS-NE vaccinated fish. The study confirmed the charged-chitosan-based mucoadhesive nanovaccine to be an effective platform for immersion vaccination of tilapia, with fish generating a humoral systemic immune response against columnaris disease in vaccinated fish

Immersion Vaccination by a Biomimetic-Mucoadhesive Nanovaccine Induces Humoral Immune Response of Red Tilapia (<i>Oreochromis</i> sp.) against <i>Flavobacterium columnare</i> Challenge

Immersion vaccination with a biomimetic mucoadhesive nanovaccine has been shown to induce a strong mucosal immune response against columnaris disease, a serious bacterial disease in farmed red tilapia caused by Flavobacterium columnare. However, the induction of a systemic immune response by the vaccine is yet to be investigated. Here, we examine if a specific humoral immune response is stimulated in tilapia by a biomimetic-mucoadhesive nanovaccine against Flavobacterium columnare using an indirect-enzyme-linked immunosorbent assay (ELISA), serum bactericidal activity (SBA) and the expression of immune-related genes within the head-kidney and spleen, together with assessing the relative percent survival of vaccinated fish after experimentally infecting them with F. columnare. The anti-IgM antibody titer of fish at 14 and 21 days post-vaccination was significantly higher in chitosan complex nanoemulsion (CS-NE) vaccinated fish compared to fish vaccinated with the formalin-killed vaccine or control fish, supporting the serum bactericidal activity results at these time points. The cumulative mortality of the unvaccinated control fish was 87% after challenging fish with the pathogen, while the cumulative mortality of the CS-NE vaccinated group was 24%, which was significantly lower than the formalin-killed vaccinated and control fish. There was a significant upregulation of IgM, IgT, TNF α, and IL1-β genes in the spleen and kidney of vaccinated fish. Significant upregulation of IgM and IgT genes was observed in the spleen of CS-NE vaccinated fish. The study confirmed the charged-chitosan-based mucoadhesive nanovaccine to be an effective platform for immersion vaccination of tilapia, with fish generating a humoral systemic immune response against columnaris disease in vaccinated fish

Sample images of activated HUVEC monolayers exposed to PLGA in different flow mediums.

<p>Phase image of 1.4 µm sLe^a-coated PLGA spheres bound to IL1-β-activated HUVEC monolayer after 5 min of flow of particles in (A) RBC-in-Buffer, (B) whole blood, and (C) plasma at 200 s⁻¹. Image taken at 20× magnification. sLe^a density  = 1500+/−100 sites/µm² (SEM). Particle concentration  = 5e5 particles/mL. Scale bar  = 20 µm</p

The average mean particle diameter (Z-average) and polydispersity indexes (PDI) for PLGA spheres in filtered phosphate buffer saline with calcium and magnesium ions (PBS+/+) are measured via dynamic light scattering (DLS) technique using a Malvern Zetasizer Nano ZSP equipped with a back scattering detector (173 degrees).

<p>The average mean particle diameter (Z-average) and polydispersity indexes (PDI) for PLGA spheres in filtered phosphate buffer saline with calcium and magnesium ions (PBS+/+) are measured via dynamic light scattering (DLS) technique using a Malvern Zetasizer Nano ZSP equipped with a back scattering detector (173 degrees).</p