Optical Force Based Detection and Characterization of Disease in Mammalian Cells

S.J. Hart, C.G. Hebert, A. Terray
LumaCyte, US

Keywords: sensors, optical force

Summary:

There is a compelling need to develop instrumentation capable of characterizing and sorting cells for medical research and disease detection that are sensitive, selective, automated, and cost effective. Our research seeks to develop laser based separations that do not rely on labels such as antibodies or fluorescent molecules for cell detection. Rather, we utilize inherent differences in optical force, which arise from variations in particle size, shape, refractive index, or morphology, as a means of separating and characterizing particles. Optical forces occur when photons reflect and refract through a transparent particle and impart momentum. In our system, individual cells are analyzed in series inside a microfluidic device using a near-infrared laser beam that exerts a physical force on the cells, which is then measured. The magnitude of the force on each cell is related to the intrinsic properties of the cell and varies across cell types and for differing diseases. Recently, changes in optical force have been measured for nano-coatings on beads that represent only very small difference in total particle size. These very sensitive measurements indicate that the use of optical force may be used for detection of small changes in cell membrane or other subtle changes within a cell. These results and other applications will be presented including cell differentiation, viral infection of cells, phagocytosis of bacteria, apoptosis, and detection of cancerous cells. These applications will be discussed in the context of automated label-free cell analysis and sorting.