Single-Cell Detection Using Optofluidic Intracavity Spectroscopy

Optofluidic intracavity spectroscopy was used to realize label-free detection of single biological cells, including yeast cells and human blood cells, as well as polystyrene spheres in a microfluidic Fabry-Perot cavity. The design, fabrication, and testing of the cavities are discussed, along with the sensing mechanism. The resonant conditions of the microfluidic cavity were modified by the cells and microspheres inside the cavity due to the effective refractive index profile of the cells. Transmission spectra of single cells in the cavity, measured using a customized microscope system, exhibited cell-type specific higher order transverse mode features, including the number of transverse modes, mode shape, and the relative mode spacing. A correlation method for the cell-induced spectra is reported and provides a preliminary demonstration that some types of single cells can be differentiated. After further development, the method may provide a useful label-free optical technique for recognizing cells in a microfluidic environment