Lifted Bottom of Microfluidic Channel for Cell Absorption Spectroscopy Using Optical Fibers

Abstract

A Si microoptical bench has been developed for measuring the absorption spectrum of cells in suspension. Optical fibers are the elements for constructing a light path inside a Si chip. The sensing light is introduced, transmitted through the sample, and detected. The light propagates in the core. A thick surrounding cladding protects the beam from optical disturbance. In many cases, the cells in suspension tend to sink to the bottom of the microfluidic channel because their density is higher than that of water. For bringing the cell in the sensing light beam, the bottom of the microfluidic channel is lifted up to the core height of the optical fiber in the device. The absorption caused by the chlorophyll of the chlorella is observed.