Developing Polyphosphate Bound Nanoparticles for Inducing Quick Blood Clotting
Ransom, Ross S.
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Administering a treatment for internal hemorrhaging in many scenarios, such as in a wartime battlefield, is challenging because the bleeding is hard to localize and cannot be stopped by external measures alone. The recent discovery of the role of polyphosphate (polyP) in the blood clotting cascade provides a unique pathway for a novel treatment of internal bleeding. This thesis seeks to develop nanoparticles containing distinct numbers of polyP chains bound to a core as a first step towards a localized blood clotting treatment. Three core particles, G4 PAMAM dendrimer, polystyrene, and gold nanoparticles, are investigated for their ability to covalently bond and provide an anchor for polyP. Gold nanoparticles (GNPs) are found to be the most effective to bind polyP of the three cores tested. GNPs of 5nm, 10nm, 15nm, and 50nm in diameter were reacted with polyP by using cysteamine and cystamine as the linker between the primary amine-polyP bond and the thiol bond on the surface of the gold nanoparticle. Centrifugation proves to be an effective purification method for gold nanoparticles, and centrifugation parameters are optimized for each sized particle to recover the maximum amount of gold nanoparticles and minimizing remaining unreacted free polyP. 10nm and 15nm gold nanoparticles are successfully and purified with the maximum number of ligands per nanoparticle (aggregation number. Blood clotting kinetics of successfully bound gold nanoparticles are then tested by mediating Factor Xa. First, polyP bound gold nanoparticles are found to influence blood clotting similarly to equal concentrations of free floating polyP, successfully providing an anchor for polyP while allowing for an impact in the blood clotting cascade. Second, while maintaining a constant concentration of polyP, 10nm gold nanoparticles of varying aggregation number are tested again for Factor Xa mediated kinetics. The aggregation number is found to not have an influence on blood clotting kinetics. The results of this study can be used to develop a nanoparticle that can localize blood clotting.