A sol–gel based fiber optic sensor for local blood pH measurements

Abstract

This paper describes a fiber optic pH sensor based upon sol–gel encapsulation of a self-referencing dye, seminaphthorhodamine-1 carboxylate (SNARF-1C). The simple sol–gel fabrication procedure is ideal for encapsulation and immobilization of dye molecules onto the end of an optical fiber. A miniature bench-top fluorimeter system was developed for use with the optical fiber to obtain pH measurements. Linear and reproducible responses were obtained in human blood in the pH range 6.8–8.0, which encompasses the clinically-relevant range. The sensor was also shown to have low coating leachability. This sensor will be used as part of an array of sensors being developed to monitor stroke patients.