Mechanical circulatory support devices and many prosthetic heart valves induce blood flow disturbances that are characterized by elevated shear stresses. As a result, many of these devices are burdened with thromboembolic risk and complications that mandate complex life-long anticoagulant/antithrombotic medication regimen for their recipients. These are applied systemically and uniformly affects the entire circulation, exposing the patients to risks of bleeding and toxicity. Here we propose a new technology for targeting clinically-used antithrombotic drugs exclusively to regions of high shear flow. Thus, potentially avoiding many of the complications of systemic delivery, while increasing its efficacy. The technology is based on DNA-origami, which allows designing of nanostructures at near- atomic precision. This proposal describes a comprehensive research and training program to prepare Dr. Oren Rotman, PhD, for an independent research career focused on developing novel nano-technological tools for targeted drug delivery in patients with cardiovascular diseases and devices. Under the mentorship of Drs. Danny Bluestein, PhD., and Nadrian Seeman, PhD., the applicant will use flow-based in vitro assays, microfluidics, computational fluid dynamics (CFD) simulations, and DNA nanotechnology methods to investigate the efficacy of the proposed technology, and do demonstrate proof of concept. Primary training objectives are to extend the candidate?s expertise in 1) DNA nanotechnology techniques, 2) advanced in-vitro blood flow testing assays, 3) turbulent CFD modeling, and 4) design and fabrication of microfluidic devices. The applicant will also undergo a comprehensive professional development plan, to be held primarily in Stony Brook University and partially in New York University. The long-term goal of this proposal is to develop a disruptive technology for shear-sensitive targeted drug delivery of antithrombotic drugs. The immediate goals are to expand the feasibility of this technology and demonstrate its proof of concept in- vitro. This will be achieved via the following specific aims: (SA1- mentored) characterization of the nano-carriers (NC) under flow in microfluidic devices (extensional flow traps and microchannels), which includes iterative process of flow testing, correlations with CFD analysis, and design modifications to the NC. Emphasis will be given on emulating shear flow patterns that are typical to cardiovascular devices. (SA2- mentored) Efficacy testing of drug-loaded NC to inhibit thrombin under controlled shear-stress patterns, both steady as well as dynamic, with emphasis on the dynamics of the application. Ultimately, (SA3- independent) testing efficacy of the drug-loaded NC to inhibit thrombin in human blood while flowing through clinically-used cardiovascular devices. The modified-prothrobinase (PAS) assay will be adopted for testing the inhibition of thrombin. By the end of this project it is expected that the proof of concept for the ability of the DNA-origami shear-responsive NCs to deliver Bivalirudin exclusively to high shear stress regions will be demonstrated in vitro. This may lead to a breakthrough of effective targeted anti-thrombotic drug delivery precision medicine for minimizing associated complications, and improving the clinical outcomes for the patients.
Current antithrombotic drug delivery affects the cardiovascular system systematically and thus exposes it to increased risks of bleeding and toxicity, in particular recipients of mechanical circulatory support devices and mechanical prosthetic heart valves. This study integrates research and training approaches to investigate a new nano-technology for targeting of antithrombotic drugs exclusively to regions of interest (e.g. aforementioned cardiovascular devices) based on characteristic blood flow patterns. This study will provide a foundation for new precision medicine technology to improve clinical outcomes in patients with cardiovascular diseases and devices.
