Collections of single cell types are used in a variety of clinical applications, notably transfusion medicine, and in diverse research applications such as vaccine development, tissue culture, and pathogen detection. In all of these applications, it is often necessary to remove unwanted media, select only the cells of a given type or size, wash away contaminants, and possibly add different reagents to the cells. A revolutionary elutriation system has recently been developed to achieve all of these functions thoroughly and efficiently, in a single processing step. Unlike conventional elutriation systems in which the cells are progressively swept away in stronger and stronger fluid flows, a unique separation chamber in the new device selectively retains only a specified range of particle sizes and densities. Designed with the aid of extensive computer programs, this new chamber has already been used to reduce residual white blood cells in red cell concentrates to the level of detection, while also removing all residual plasma. The goals of this project are to extend and refine the capabilities of this prototype. First, because the prototype is currently limited to the relatively narrow size range of red blood cells, the device will be modified to handle the entire size range of the buffy coat, extending from the smallest platelets to the largest monocytes. Although not of immediate clinical use, this extended capability is necessary to demonstrate the wide range of cells that the technology can handle. Next, the device will be used to process platelets to demonstrate clinical utility. The problems to be addressed include the need to leukoreduce the platelets without excessive cell loss, remove residual plasma, and remove most of the bacterial contamination. If successful, this technology can then be applied in all cellular manufacturing processes, including recombinant work and genetic engineering technologies. Relevance to Public Health: Single cells are the smallest units of life. In clinical practice, this new technology can clean and sort single blood cell types, thereby making transfusions safer and more effective. In research and emerging manufacturing applications, this new technology can prepare better cells for vaccine development, tissue culture, and disease outbreak detection. [unreadable] [unreadable]