A novel thermometer-type hydrogel senor for glutathione detection

A thermometer-type visual sensor for glutathione (GSH) sensing was developed with stimulus-responsive fluorescent hydrogel which was obtained by using 5, 6-bicarboxylic fluorescein crossli`nked partly ammoniated polyacrylamide. Various experimental parameters such as the particle size of hydrogel, buffer solution and swelling time were optimized. It is accessible to measure the volume change of hydrogel with the sensor by reading the graduation on a pipette like thermometer with naked eye. The concentration of the GSH depended on the volume in a certain range as the signal. Satisfactory agreements between the sensor and HPLC results for atuomolan tablet assays indicated the capability of the thermometer-type sensors for the analysis of real samples. These findings proved the utility of stimulus-responsive, intelligent hydrogel and the suitability of thermometer-style visual sensor design for quantitative assays. 5,6-dicarboxylic fluorescein (5,6-DCF) cross-linked amine-functionalized polyacrylamide (PAM) hydrogel for volumetric response to glutathione. Photographic images of the hydrogel sensor and its responses to glutathione which can be quantitatively distinguished like a thermometer-style by the naked eye. [Display omitted] •A thermometer-type sensor with convenience, smartness, low-cost versions was developed with stimuli-responses of hydrogel.•The sensor undergoes volume response to glutathione, which enables naked-eye detection by reconstructed pipette.•The challenge for the difficulty of measuring hydrogel volume changes became easy.•Our design stands out visual detection without instruments or power sources.