Simple and Precise Preparation of a Porous Gel for a Colorimetric Glucose Sensor by a Templating Technique

Red for danger! A glucose‐sensitive gel is systematically prepared by careful control of the gel recipe to produce the desired swelling ratio at a given glucose concentration. Subsequently, a periodically ordered porous gel is obtained from the bulk gel by using a closest‐packing colloidal crystal as a template; this template is subsequently removed. The gel exhibits expected structural color at certain glucose concentrations and thus can be used as a colorimetric glucose sensor, which may applied as a test for diabetes (see picture).