Presumably the pig beta cells will produce insulin when blood glucose is higher than normal pig blood glucose, whatever that is. The concept has been tested quite successfully with alginate encapsulated pig beta cells. But participants soon needed to supplement the insulin with injections. A trial subject in Auckland still had some beta cell function left after 9 years.
The encapsulation option seems more viable as the islets can be injected. Implanting this device would require a surgical procedure. By far the biggest hurdle will be negotiating the xenotransplantation issue and dealing with all the emotion it arouses.
