Raman imaging of neoplastic cells in suspension

摘要

The combination of Raman spectroscopy and Optical Tweezers has been used to trap living cells and collect information about their biochemical state. Cells can continue living in such traps for periods of hours, allowing acquisition of time resolved Raman spectra. However no spatial information can be acquired as the cells continue to rotate and move in the single beam trap. Here we describe the development of Holographic Optical Tweezers (HOT) for the controlled movement of floating cells in order to construct their Raman images. Instead of a single trap, rapidly programmable multiple trapping points can be produced around the periphery of the cells to impede the rotational motion of the cell. By trapping and scanning the cell using HOT relative to a fixed Raman exciting laser, a point by point image of the cell can be constructed. We use an interactive program that permits us to position the trapping points relative to the live image feed we see from the microscope, using point and click. To demonstrate the possibilities of this technique images are shown of floating Jurkat cells.