Figure 2.

Implantable devices for blood-glucose monitoring. (a) Hydrogel-modified fibre with fluorescence responsivity operating in the ears of mice and responding to blood-glucose levels. Adapted with permission from Yun Jung Heo et al. [73], (b) Subcutaneous device with boronic acid-based glucose responsive fluorescent dye protected within a hydrogel doped by antioxidant enzymes. Adapted with permission from Sawayama et al. [74].