Extensional flow-based microfluidic device: deformability assessment of red blood cells in contact with tumor cells

Red blood cell (RBC) deformability has become one of the important factors to assess blood and cardiovascular diseases. The interest on blood studies have promoted a development of various microfluidic devices that treat and analyse blood cells. Recent years, besides the RBC deformability assessment, these devices are often applied to cancer cell detection and isolation from the whole blood. The devices for cancer cell isolation rely mainly on size and deformability of the cells. However, the examination of deformability of the RBCs mixed with cancer cells is lacking. This study aims at determining the deformation index (DI) of the RBCs in contact with cancer cells using a hyperbolic microchannel which generates a strong extensional flow. The DIs of human healthy RBCs and human RBCs in contact with a tumor cell line (HCT-15, colon carcinoma) were compared by analyzing the flowing RBCs images captured by a high speed camera. The results reveal that the RBCs that were in contact with HCT-15 cells have lower deformability than the normal RBCs.The authors acknowledge the financial support provided by: Student Mobility Placements with the program Lifelong Learning (Erasmus Program), 2007 Global COE Program “Global Nano-Biomedical Engineering Education and Research Network”, Japan. Grant-in-Aid for Science and Technology (PTDC/SAU-BEB/105650/2008, PTDC/EME-MFE/099109/2008 and PTDC/SAU-ENB/116929/2010) from the Science and Technology Foundation (FCT) and COMPETE, Portugal. The authors are also very grateful to Professor Mónica S.N. Oliveira (Strathclyde University), Professor Geyong M. Kim (University of Navarra) and Professor Sergio Arana (University of Navarra) for their discussion and suggestions to this research work