Abstract

In this study, an optical signal recording method for optogenetics stimulation of ChR2 channels expressed in human pulp dental (HPD) cells by using a fiber optic refractive index (RI) sensor based on all fiber Mach-Zehnder interferometer was proposed. All-fiber Mach-Zender interferometric biosensor is composed of a specially fabricated twin-core fiber spliced between two pieces of a single-mode fiber which one of the cores was doped with germanium and the other with phosphorous [1]. The interference pattern in the fiber Mach-Zehnder interferometer is occurred by coupling of the propagation lights of both fiber cores. For coupling the light into both cores, a short length of a coreless fiber optic was used. The length of twin-core fiber was 40 cm. Here, one core of the fiber acts as a reference arm and the other cores as sensing arm. For increasing evanescent wave around the sensing arm of the fiber optic biosensor, a short section of the cladding of the twin-core fiber about 2 cm was etched with HF solution. For this propose, after determining the direction of the cores so that the two cores were in the vertical direction, one side of the twin-core fiber was fixed on Plexiglas substrate by using UV glow and the upper side of the sensor was etched.

© 2019 IEEE