This manuscript reports the application of the selective-withdrawal coating technique to the microencapsulation of insulin-producing pancreatic islets within thin poly(ethylene glycol) coatings. These polymer coatings permit the islets to respond to changes in glucose concentration by producing insulin with a dose-response profile that is substantially similar to that of unencapsulated islets. Furthermore, the hydrogel capsules exclude the large molecules of the immune system. These results suggest that the microencapsulation technique-which combines droplet formation from a flow of two immiscible fluids with polymerization chemistries-has the characteristics required for the transplantation of islets for the treatment of Type I diabetes.

After the publication of this article, the corresponding authors discovered that the results of Figure 6 could not be reproduced. Upon bringing this matter to the attention of the University of Chicago Academic Fraud Committee, the Committee came to the conclusion that Matthew Connors fabricated these data. The Committee determined that there was no evidence that the rest of the authors engaged in unethical behavior or were aware of the data being fabricated. No questions were raised with respect to the results describing the design of the apparatus for the selective withdrawal method and the photochemical cross-linking of a polymeric shell around the islets. The corresponding authors and the rest of the authors (other than Matthew Connors) have requested and agreed to this retraction.