Double-pass Mach–Zehnder fiber interferometer pH sensor
Tou, Zhi Qiang
Chan, Chi Chiu
Tan, Eddie Khay Ming
Tan, Terence Aik Huang
Date of Issue2014
School of Chemical and Biomedical Engineering
A biocompatible fiber-optic pH sensor based on a unique double-pass Mach–Zehnder interferometer is proposed. pH responsive poly(2-hydroxyethyl methacrylate-co-2-(dimethylamino)ethyl methacrylate) hydrogel coating on the fiber swells/deswells in response to local pH, leading to refractive index changes that manifest as shifting of interference dips in the optical spectrum. The pH sensor is tested in spiked phosphate buffer saline and demonstrates high sensitivity of 1.71 nm/pH , pH 0.004 limit of detection with good responsiveness, repeatability, and stability. The proposed sensor has been successfully applied in monitoring the media pH in cell culture experiments to investigate the relationship between pH and cancer cell growth.
Journal of biomedical optics
© 2014 Society of Photo-Optical Instrumentation Engineers. This paper was published in Journal of Biomedical Optics and is made available as an electronic reprint (preprint) with permission of Society of Photo-Optical Instrumentation Engineers. The paper can be found at the following official DOI: http://dx.doi.org/10.1117/1.JBO.19.4.047002. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.