Laser Power Dependent Oxygenation States of Normal and Sickle Red Blood Cells

Friday, October 28, 2011
Hall 1-2 (San Jose Convention Center)
Lena Zheng , NSF Center for Biophotonics Science and Technology, Sacramento, CA
Rui Liu, Masters , NSF Center for Biophotonics Science and Technology, Sacramento, CA
James Chan, PhD , Center for Biophotonics Science and Technology, University of California, Davis, Sacramento, CA
Optical tweezers have become widely used for the manipulation and analysis of individual

biological cells. A simple and most commonly used configuration is the single beam optical trap in

which a tightly focused laser beam optically immobilizes individual cells within the laser focus. The

perturbative effect of an optical trap operating under such a tight focusing condition on the function

and biochemistry of a live cell is often a concern, with photoinduced damage typically being a primary

focus. Mechanically induced biochemical changes, however, have not been as extensively studied,

even though it is known that optical forces are imposed on a biological cell by a single beam optical

trap that are often strong enough to modify its shape. Herein, we report that a red blood cell (RBC) in a

single beam optical trap transitions from an oxygenated to a partially deoxygenated state with

increasing trapping power using laser tweezers Raman spectroscopy (LTRS). In addition, the

oxygenation states of different types of red blood cells, such as sickle cells and normal adult red blood

cells, reacts differently with the increased optical trapping power ranging from 1.6mW to 20mW,

which provides the rationale for function analysis of the oxygen carrying capacity of different types of

RBCs.