Polymers for the rapid and effective activation and aggregation of platelets

Platelets are responsible for plugging sites of vascular injury, where upon activation they spread out and become cross-linked, preventing further blood loss. It is desirable to control the activation process on demand for applications such as the rapid staunching of blood flow following trauma. Polymers are the material of choice in many biological areas, with physical properties that allow control of morphology as well as ease of functionalisation and production. Herein, polymer microarrays were used to screen a complex human fluid (platelet rich plasma) to identify polyacrylates that could be used to modulate platelet activation. Several polymers were identified which rapidly activated platelets as determined by CD61P binding and subsequent confirmation by scanning electron microcopy analysis. This approach enabled a direct comparison between the natural agonist collagen and synthetic polymers with respect to the activation status of the platelets as well as the number of bound platelets. Further investigations under physiological flow demonstrated that the static microarray experiments gave viable candidates for potential medical applications while specific protein binding to the polymers was identified as a possible mode of action. The approach demonstrates the ability of polymer microarrays to identify new polymers for specific biological activation events and in this case allowed the identification of materials that allowed higher levels of platelets to bind in advanced activation states than the natural standard collagen in static and flow studies.