Micro- and Macroencapsulation: Firms Try Different Approaches to Protect Islets

Just as islet research is developing at the university level, corporations are taking steps toward creating devices and technologies to aid islet transplantation.

One such company is VivoRx, founded by Patrick Soon Shiong, MD, who reports that VivoRx is making strides in technology to proliferate islets and to encapsulate them.

Proliferating islets is necessary for islet transplantation. Currently, not enough donor pancreases exist, making it difficult to obtain enough islets to transplant into all those who would benefit from an islet transplant. Proliferation involves reproducing human islets, so you can start with just one islet, but make enough for a successful transplant.

ViviRx is pursuing this technology, having abandoned its attempts to transplant porcine (pig) islets into humans.

“We made a decision, based on scientific and safety issues, to go back to human islets,” says Soon Shiong, citing the identification of viruses from pig islets as a potential danger.

In proliferating human islets, Soon Shiong and his team have identified “progenitor cells,” which are “not exactly” stem cells, but “early cells” that can be manipulated to secrete insulin.

“This work is still preliminary,” reports Soon Shiong.


VivoRx also has microencapsulation technology, the goal of which is to protect transplanted islets from the body’s immune system. Islets are placed in VivoRx’s own capsule technology, where the hope is they will be protected without the need for immunosuppressive drugs. Soon Shiong’s team will begin clinical trials on type 1 humans without immunosuppression.

Macroencapsulation: Islet Sheet Medical

Islet Sheet Medical, started by type 1 Scott R. King, is working on a different method of protecting islets. It is called macroencapsulation. Instead of encapsulating each islet individually (called microencapsulation), it encapsulates many islets, up to about 160,000, to be exact. It’s done with the company’s namesake, an islet sheet.

But, what is an islet sheet? According to King, “It’s like a really big contact lens.” Like other encapsulation devices, it has to keep the body’s immune attack forces out, allow in substances necessary to keep the islets working, and let out insulin. King says the sheet has proven it can do all of this in dogs, and he looks forward to beginning more trials.

Leave a Reply

Your email address will not be published. Required fields are marked *

Time limit is exhausted. Please reload CAPTCHA.