Notably, not only was the percent of RPVIM devices showing signal significantly greater than SIM and SPVIM devices, but the intraperitoneal glucose tolerance tests and histological analyses showed that encapsulated stem‐cell derived insulin‐producing beta cell clusters retained their function in the RPVIM devices, which is crucial for the successful management of T1D. The gene discussed is INS; the disease is type 1 diabetes mellitus.