Abstract

Analysis of S-Nitrosothiols Using Paper-based Microfluidic Device (µPAD) by Colorimetry: Kinetics of Decomposition and Quantification

Abdulghani Ismail, Researcher, Chimie ParisTech, Unité de Technologies Chimiques et Biologiques pour la Santé

A disposable microfluidic paper-based analytical device (µPAD) was developed to easily analyze different S-nitrosothiols (RSNOs) through colorimetric measurements. RSNOs are carriers of nitric oxide (NO) that plays several physiological and physiopathological roles. The quantitation of RSNOs relies on their decomposition using several protocols and colorimetric detection of the final product, NO or nitrite. µPADs were fabricated by wax printing technology in a circular geometry for decomposition and detection of decayed products interconnected by microfluidic channels and one central sample inlet zone.  Different decomposition protocols including mercuric ion and light (UV, Visible, and Infrared) were tested on µPADs. A 3D printed holder was coupled with µPADs to make easy a simultaneous decomposition procedure using different light sources. Griess reagent was then added to detect NO and nitrite produced by the different decomposition methods. µPADs were then scanned using a flat board scanner. The limit of detection (LOD) values for nitrite and S-nitrosoglutathione (GSNO) using mercuric decomposition were 3 µM and 4 µM, respectively. The LOD reported herein is considered one of the lowest LOD already reported using paper microfluidic devices. The results also show that low molecular weight RSNO, namely S-nitrosocysteine decomposes more easily than high molecular weight RSNOs by light.