A smart hydrogel system for visual detection of glucose.

Glucose sensing is of vital importance due to the growing number of diabetes. In this study, we developed a visual detecting approach for glucose sensing based on a smart hydrogel system, by assembling of a photo-crosslinkable hydrogel and a pH-responsive nanogel, respectively. The hydrogel system showed fast response and high sensitivity to glucose in the physiological ranges, and enabled a visual detection of glucose both in vitro in glucose solutions and in vivo in diabetic mouse models. In normoglycemic state, the hydrogels showed large swelling, resulting in a large shape but with weak color or fluorescence intensity of the hydrogels. In hyperglycemic state, the hydrogels exhibited less swelling, resulting in a small shape but with strong color or fluorescence intensity of the hydrogels. Based on the observation of the size change and intensity change of the hydrogels, we can visual the glucose levels by either colorimetry or fluorescence imaging. This hydrogel system provides a novel means for visual detection of glucose. Our study broadens the current applications of hydrogels, extending their potentials in clinical diagnosis of diabetes or glucose-related analysis.