MICROFLUIDIC SAMPLE PREPARATION OF PLEURAL EFFUSIONS FOR CYTODIAGNOSTICS Albert J. Mach 1 , Derek E. Go 1 , James Che 1 , Ish Talati 1 , Yong Ying 2 , Rajan Kulkarni 3 , Jianyu Rao 2 , Dino Di Carlo 1 1 Deparment of Biomedical Engineering, University of California, Los Angeles, USA, 2 Department of Pathology and Laboratory Medicine, UCLA, USA, 3 Department of Dermatology, UCLA, USA ABSTRACT Pleural effusions – fluids that build up surrounding the lungs - can harbor malignant cells which are important to identify for diagnosis of cancer. However, rare malignant cells may lead to misleading diagnoses and a large background of leukocytes can prevent accurate identification of mutations of interest for targeted anti-cancer therapies. We developed a miniaturized microfluidic system that employs microscale vortices for the size-based isolation of malignant cancer cells and mesothelial cells. By processing mL volumes of pleural effusions and enriching target cells over a background of blood cells, we replace the traditional centrifugation step in the clinical lab. We demonstrate higher purity in 100% of the samples (n=30) where cells are made readily available for immunolabeling, standard cytology analysis and molecular analysis. KEYWORDS Laminar Microvortices, Liquid-Based Preparation, Inertial Microfluidics INTRODUCTION Pleural fluids abnormally accumulate in patients with cancer or other diseases and are extracted to determine the cause and to provide relief to the patient. Cytopathologists analyze pleural samples to determine the cause (presence of absence of cancer) by examining stained cell smears on a glass slide prepared via centrifugation and labeling [1]. However, blood cell components (leukocytes/erythrocytes) and other non-cellular materials in the sample create a background, making it difficult to locate potentially malignant epithelial cells of interest over a large field of view necessary for diagnostic accuracy. Harvesting large quantities of tumor cells in high purity could improve cytology-based diagnoses. We have previously demonstrated a miniaturized microfluidic system that recapitulates the high-throughput operations of enrichment and concentration of a standard laboratory centrifuge [2]. Here, we use the “Centrifuge Chip” for the isolation of larger cancer cells and mesothelial cells at high purity from complex biological fluids such as pleural effusions as a preparation step for analysis by traditional cytology. By processing a large volume of fluid and selectively enriching larger cells over a background of red and white blood cells we replace the traditional centrifugation step in the clinical lab while also potentially enabling more sensitive analysis of pure preparations originating from a larger volume. Figure 1: Device Design and Setup. (a,b) Schematic of selective cell trapping in a single microscale vortex and parallel device design. (c) Artist rendering of cancer cell capture from a bloody pleural sample (d,e) Centrifuge Chip device connected to an automated fluidic instrument to deliver patient pleural samples and saline wash through the Centrifuge Chip into the waste bottle. Trapped epithelial cells are made readily available 1) into a collection tube for further cytology slide comparisons with the original (Fig. 4) and/or 2) a well-plate for immunolabeling, imaging and analysis. 16th International Conference on Miniaturized Systems for Chemistry and Life Sciences October 28 - November 1, 2012, Okinawa, Japan 978-0-9798064-5-2/μTAS 2012/$20©12CBMS-0001 803