pH-sensing capsules that deliver optimal quantity of insulin under development

Researchers at Switzerland's ETH Zurich tested a molecular implant in mice that constantly monitors the blood's acidity and produces insulin.--Courtesy of ETH Zurich

Researchers at Switzerland's ETH Zurich say they successfully tested in mice a molecular implant that contains gene-based mechanisms for delivering insulin based on feedback from an associated pH biosensor. By maintaining a healthy pH level between 7.35 and 7.45, the therapy, consisting of different genes and proteins, would prevent potentially fatal metabolic shock (ketoacidosis) in diabetics.

The team delivered the therapy within millions of renal cells that were packaged into capsules, says the university's news release. In a study described in the journal Molecular Cell, the experimental mice controlled their insulin level in a manner similar to their healthy counterparts.

According to the study abstract, the team accomplished the feat by "functionally rewiring the human proton-activated cell-surface receptor TDAG8." The implant not only measures pH level via a molecular signaling cascade, it also coordinates the body's response to bring the pH level down from the high levels associated with Type 1 diabetes.

ETH Zurich says that this development is different from previous attempts to create a synthetic method of regulating insulin levels because the therapy relies on methods that are endogenous to the human body, for the TDAG8 surface receptor already exists in humans (though it must be rewired for the new task) and interprets signals that are naturally occurring. In contrast, a previous implant developed by the team of researchers had to be activated with a blue light.

"Applications for humans are conceivable based on this prototype, but they are yet to be developed," said ETH Zurich biotechnology professor Martin Fussenegger in the news release. "We wanted to create a prototype first to see whether molecular prostheses could even be used for such fine adjustments to metabolic processes." It appears that the answer to Fussenegger's query is "yes."

He added that the assistance of an industrial partner would be needed to commercialize the technology for human diabetics. Other possible applications of the breakthrough include uses in biopharmaceutical manufacturing and "lab-on-a-chip" technology.

- read the university news release
- here's the study abstract