Currently, the FDA mandates that platelets be stored at 22-24 degrees Celsius for a maximum of five days. The short shelf life and storage conditions create supply limitations, increase costs and increase the risk of bacterial Contamination. The long term project objective is to commercially develop a platelet preservative that will allow extended 4 degrees Celsius or lower storage of platelets. The addition of a cell permeant calcium chelator (EGTA-AM) and cytochalasin B, an inhibitor of actin filament polymerization, have been shown to be reversible inhibitors of cold induced platelet shape change and the subsequent reduction in platelet function that accompanies shape change. The hypothesis is that preserved platelets stored at 4 degrees Celsius for up to 21 days will perform in a superior or equivalent manner in in vitro platelet function assays than 5-day-old conventionally stored platelets. The hypothesis will be tested by Comparing 5-day-old conventionally stored platelets to preserved platelets stored at 4 degrees Celsius for increasing lengths of storage time in the following assays: platelet morphology, platelet aggregation, hypotonic stress response, pH, cell count, and flow cytometric analysis of platelet surface markers including but not limited to P-selectin, CD6I, and annexin V. Positive statistical results in 50% or more of the assays will justify further product development. PROPOSED COMMERCIAL APPLICATION: Commercial applications include the development of a platelet additive solution that would extend the current 22 degrees Celsius, 5 day storage for up to 3 weeks at 4 degrees Celsius. The potential benefits of this technology would include increased flexibility in platelet inventory, storage, outdating and shipping requirements and diminished risk of bacterial contamination. In addition, a three-week storage would allow autologous donation for chemotherapy and surgical candidates, thus reducing the risk of infectious disease transmission and HLA incompatibilities.