Blood Separation in Microfluidic Devices Group #5 Eric Chung Scott Darby Casey Reynolds Jeff Turner

Background Microfluidic Devices: ▫Uses:  Point-of-care diagnosis  Low-Cost for mass production  Laminar Flow White Blood Cells: ▫Comprise most of the adaptive immune response ▫Intercellular Pathways must be completed for activation TypeFunction%in Humans Neutrophil Defense against infection 65% Eosinophil Parasitic Infection 4% Basophil Allergic responses 1% Lymphocyte Immune System 25% Monocyte Vacuum Cleaner ~3% Macrophage Phagocytosing macrophage ~3%

Whole Blood Valve Bank (With Fluorescent Dyes A, B, and C) Reverse Aspiration Pump Close-up of Device Valve Pressure Releases Specific Dye Marker (C) Direction of Flow Confocal Microscope Direction of Experiment Red Blood cells, unaffected by dye, and free to flow through filters. B-Cells, marked with dye marker C and contained within traps. Other types of Leukocytes, unaffected by dye. PDMS Traps

Current Technologies Flow Cytometry (FACS) ▫High cost ▫Requires relatively large fluid samples ▫Size limitations ▫Only analyzes large numbers of cells ▫No time scale

Design Objectives To create: ▫A microfluidic blood cell sorter used for taking multiple measurements of single B-cells over time  Physical Size  CD markers ▫A novel pump system using reverse aspiration ▫A valve bank that allows for regulated inputs in real-time  Reduces opportunity for air bubble formation

Device Uses Trapping and targeting of white blood cells, focusing on B-cells Identifying disease specific pathways ▫Can find specific action of pathogen to enhance targeting of drugs Regulation of a variety of inputs with a single input source

Valve Bank Pressure Valves

Microfabrication – Blood Sorter Device constructed from PDMS plasma bonded to glass cover sheet

Whole Blood Valve Bank (With Fluorescent Dyes A, B, and C) Reverse Aspiration Pump Close-up of Device Valve Pressure Releases Specific Dye Marker (C) Direction of Flow Confocal Microscope Direction of Experiment Red Blood cells, unaffected by dye, and free to flow through filters. B-Cells, marked with dye marker C and contained within traps. Other types of Leukocytes, unaffected by dye. PDMS Traps

Questions What is the most efficient flow rate for cell trapping? What cell markers elicit the best response from B-cells? Does reverse aspiration provide adequate pressure to flow whole blood? Can a valve bank be utilized without introducing air into such a sensitive system? Will this process be detrimental to cell integrity to a point where test results are unreliable?

Progress Completed: ▫To create a flow system powered by reverse aspiration ▫Receive approval for human blood experimentation ▫To successfully separate white blood cells from whole blood In Progress: ▫To create a valve bank capable of switching chemical reagents while maintaining continuous flow Long Term: ▫To simulate intermediary cell cycle steps with our trapped cells