Microencapsulation of pancreatic islets for the treatment of Type I Diabetes Mellitus (T1DM) generates a high

quantity of empty microcapsules, resulting in high therapeutic graft volumes that can enhance the host

’

s immune

response. We report a 3D printed micro

fl

uidic magnetic sorting device for microcapsules puri

fi

cation with the

objective to reduce the number of empty microcapsules prior transplantation. In this study, INS1E pseudoislets

were microencapsulated within alginate (A) and alginate-poly-L-lysine-alginate (APA) microcapsules and pur-

i

fi

ed through the micro

fl

uidic device. APA microcapsules demonstrated higher mechanical integrity and stability

than A microcapsules, showing better pseudoislets viability and biological function. Importantly, we obtained a

reduction of the graft volume of 77.5% for A microcapsules and 78.6% for APA microcapsules. After sub-

cutaneous implantation of induced diabetic Wistar rats with magnetically puri

fi

ed APA microencapsulated

pseudoislets, blood glucose levels were restored into normoglycemia (< 200 mg/dL) for almost 17 weeks. In

conclusion, our described micro

fl

uidic magnetic sorting device represents a great alternative approach for the

graft volume reduction of microencapsulated pseudoislets and its application in T1DM disease.