GCG and type 2 diabetes mellitus: For patients with type 1 diabetes, insulin replacement is important to regulate blood glucose levels (BGLs) by mimicking natural fluctuations in insulin levels.10 For type 2 diabetes, exercise and regulation of meals can effectively delay disease progression.7 But for advanced type 2 diabetic patients, injection of insulin or other diabetic therapeutics, like glucagon‐like peptide 1 (GLP‐1), are also required to control the BGLs.10, 11 However, the traditional subcutaneous injection is painful and inconvenient.