Authors:
Rutjaphan Kateklum
1
;
Bernard Gauthier-Manuel
1
;
Christian Pieralli
1
;
Samlee Mankhetkorn
2
and
Bruno Wacogne
3
;
1
Affiliations:
1
FEMTO-ST Institute, Univ. Bourgogne Franche-Comté, CNRS, France
;
2
Center of Excellence in Molecular Imaging, Chiang Mai University, Thailand
;
3
INSERM CIT1431, Besançon University Hospital, France
Keyword(s):
in Vivo pH Sensing, Fluorescence, Optical Fiber, pH Sensor, Modelling, Calibration Free Measurement.
Abstract:
Organic functions of the human body are related to biological constants. Variations of these constants, among
them pH, induce pathological troubles. The general goal of our work is to fabricate a fluorescent pH sensor
at the end of an optical fiber for in vivo pH measurements. One difficulty using fluorescence indicators is the
need to perform an accurate calibration. In this communication, we present methods used to simplify and
potentially avoid calibration procedures of fluorescence indicators. The first method concerns the
simplification of calibration procedures making them independent of the indicator’s concentration, path length
and equipment used. The second method concerns modelling the fluorescence emission of the molecules as a
function of pH only. This model is used to fit the exact shape of C-SNARF-1 fluorescence spectra obtained
at any pH. Subsequently, the pH of a solution can be computed with an accuracy of 0.1 pH unit without the
calibration procedure employ
ed up to now. These methods constitute the first steps toward calibration free
pH measurements. They can be applied to any fluorescent indicator exhibiting a dual emission peak. As a
conclusion, this is the first time that fluorescence properties of C-SNARF-1 are fully mathematically
described.
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