The present study, aims to investigate and compare the effect of insulin and embryonic stem cells (ESC) loaded nanoparticle formulations (NPs) on pancreatic-beta-TC-cell regeneration. Characterization studies of NPs were performed. Permeability of insulin and the effect of ESC on pancreatic beta cells were investigated. Insulin or glucose levels were determined and histologic investigations were also performed. ESC encapsulation efficiency was calculated by western blot analysis. The particle sizes of insulin and ESC-loaded-NPs were determined as 0.665 +/- 0.202 mu m and 0.650 +/- 0.310 mu m. The mean zeta potentials of insulin and ESC-loaded-NPs nanoparticles were found as 6.88 +/- 0.729 mV, 5.13 +/- 0.631 mV. The polydispersity index of insulin and ESC nanoparticles were 0.660 +/- 0.175, 0.620 +/- 0.205 respectively. Encapsulation efficiency of insulin and ESC-loaded-NPs were found to be 50 +/- 1.53% and 51%. Insulin release from nanoparticles was found to be 72.8% over 48h. Glucose concentrations were decreased to 201 and 202.7 mg/dL from 250 mg/dL in streptozocin (STZ) induced diabetic mice group after insulin and ESC-loaded-NPs administration. Insulin and ESC-loaded-NPs improved the blood insulin levels in all experimental groups. These NPs may be used for repairing of pancreatic cells. Healing or some degree of regeneration was observed when insulin and ESC-loaded-NPs were administered to mice. ESC-loaded-NPs can be a potential source for cell replacement therapy in the treatment of diabetes.