At the injection session, the research nurse will perform a single standard antecubital blood draw (35 mL). The PRP will be obtained from this sample using a two-stage spinning technique: the 1st separates red blood cells from platelets, and the 2nd concentrates the platelets to yield approximately 4 mL of concentrated autologous platelet. This layer of platelet rich plasma will be placed in the syringe by the centrifuge machine.