Peptide-Modified Sulfonated Styrene Block Copolymers for Vascular Applications

Period of Performance: 04/15/2008 - 08/31/2009


Phase 1 SBIR

Recipient Firm

Aegis Biosciences, LLC
Spokane, WA 99202
Principal Investigator


DESCRIPTION (provided by applicant): A novel sulfonated polymer with unique chemically tailorable properties and processing characteristics has shown considerable promise as a thrombo- resistant surface and has been proven to be effective inhibitor against neutrophil- derived proteases. A phase 1 SBIR testing is proposed to investigate this polymer as a tailorable interface coating for blood-contact biomaterial substrates. The major specific aims of the proposed research involves the fabrication and investigation of several chemically modified versions of the sulfonated polymer, not only to minimize platelet adhesion and activation, but also, to encourage the shear-stable attachment and proliferation of healthy endothelial cells. This innovative and rational approach to a bioengineered, biomimetic, & thromboresistant blood contacting biomaterial surface is founded on the basis of several different studies that have revealed promising bioapplicable attributes of this polymer. The end-goal of this Phase 1 SBIR is to develop and identify an inherently non-thrombogenic, endothelialized and antiinflammatory hydrogel surface with application to a wide array of lifesaving cardiovascular devices.Project Narrative: Cardiovascular disease is the leading cause of death and disability for both men and women in the U.S., affecting more than 70 million Americans at present. Overall, more than 6 million hospitalizations occur each year for treatment of cardiovascular diseases. Consequently, the economic impact of cardiovascular diseases on our nation's health care system continues to grow, especially as the population ages. The cost of heart disease and stroke in 2006 (U.S.) was greater than $400 billion, when healthcare cost expenditures and lost productivity from death and disability are accounted for. Under the umbrella of cardiovascular diseases, atherosclerosis-induced peripheral artery disease (PAD), coronary artery disease (CAD) and cerebrovascular disease all suffer from the primary event of vessel narrowing (stenosis) and/or occlusion due to dysregulated formation of clots and associated inflammatory events involving smooth muscle cell (SMC) infiltration, neointimal proliferation and maladaptive vascular remodeling. Stenosis and occlusion lead to reduction/loss of antegrade blood flow. For PAD, this may lead to claudication and tissue morbidity of peripheral extremities, while for CAD this can lead to ischemia and often fatal myocardial infarction and, for cerebrovascular situations, this may lead to stroke. Interventional endovascular and/or surgical treatment to remove thrombus and to reestablish vascular flow is necessary for clinical management of these diseases. Endovascular treatments involve mechanical approaches like catheter-mediated angioplasty, cryoplasty and enderactomy and, pharmacotherapeutic approaches like transcatheter delivery of thrombolytic, anti-platelet and anti-proliferative drugs. Often these approaches are combined with stenting. Recent years have seen the development of drug eluting stents (DES) where the metal stent surface is coated with a drug-loaded polymer matrix for sustained release of therapeutic agents. Surgical approaches involve bypass grafts, many of which are made of synthetic polymers (e.g. ePTFE). For other cardiovascular diseases biomaterials also play an important role. Devices including pacemakers, ventricular assist devices, and the total artificial heart are used. All of the aforementioned devices depend upon synthetic materials that come into contact with flowing blood. These materials are prone to rapid protein (e.g. fibrinogen, fibrin) deposition, denaturation and subsequent adhesion and activation of blood platelets potentially leading to clot formation and the subsequent activation of coagulation and inflammatory events. In turn, material performance can be compromised necessitating recurring endovascular or surgical procedures. As such, these patients generally require perpetual anticoagulation therapy in order to prevent stroke and/or device failure. Thus, protein- and platelet-resistant blood-contacting interfaces on devices as mentioned above can improve patient outcomes and reduce the overall cost of care. In this application, an interface material of novel design that leverages the functional tailorability of a novel polymeric biomaterial is the subject of our investigation. The polymer is a sulfonated block copolymer which is non-thrombogenic and can be readily modified to include one or more biofunctional therapeutic agents and/or cell-signaling molecules as a means of guiding the `healing response' to the designer surface. We anticipate that the designer surfaces resulting from these studies will provide an extremely efficient surface-modification treatment for blood-contacting biomaterials, at a reduced cost when compared to current treatment regimens.