GCG and type 2 diabetes mellitus: Furthermore, as a proof-of-concept, we show that subcutaneously implanted microencapsulated Glow-controlled engineered human cells can effectively treat diabetes and associated symptoms, including postprandial hyperglycemia, insulin resistance, fasting blood glucose levels, and obesity, in a mouse model of type-2 diabetes by means of percutaneously remote-controlled release of human glucagon-like peptide-1 (hGLP1) using programmed green-light illumination.