Polarization Raman study of protein ordering by controllable RBC deformation

Polarized Raman spectroscopy is used to provide evidence of hemoglobin protein ordering as the red blood cell (RBC) is stretched with optical tweezers. The stretching of the cell is intended to mimic the deformation that it experiences as it travels through vessels and capillaries. The depolarization ratios for a number of heme Raman bands change as the cell is stretched, confirming the semi‐ordered nature of the hemoglobin ensemble in the cytoplasm. Furthermore, trends observed in the ratio shifts point to increased packing and ordering of the Hb after cell stretching. This evidence should shed more light on to the role of deformation in the RBC function. Copyright © 2009 John Wiley & Sons, Ltd. Red blood cells are stretched using optical tweezers while simultaneously recording their Raman spectrum. The depolarization ratios of the heme Raman bands change upon stretching, which indicates the existence and deformation‐induced altering of protein ordering in the cell. The result points to a larger role of deformation in the functionality of the red blood cell.