A form of long-acting insulin that automatically activates itself in response to blood sugar levels has been engineered by scientists in the US.
Treatment with insulin has revolutionised the control of the disease diabetes, which occurs when individuals cannot produce enough of the hormone.
This leads to high blood sugar levels and damage to organs including the eyes, kidneys, nervous system and blood vessels.
However, despite rigorous compliance with treatment, diabetics are still at risk of side effects caused by low and high blood sugar levels because administering just the right amount of insulin by injection is difficult.
Now Daniel Anderson and his colleagues at MIT have engineered a form of insulin that circulates in an inactive state in the blood for an extended period and springs to life in response to blood sugar levels.
Their new agent comprises an insulin molecule coupled to a fatty-acid hydrocarbon chain that binds onto the proteins in the bloodstream.
At the end of this chain is a molecule called phenylboronic acid (PBS), which acts as a glucose sensor, releasing the insulin from its coupling to the plasma proteins only when needed in response to high blood glucose.
Injected into mice with the rodent equivalent of diabetes, the new drug controlled blood sugar levels including infusions of sugar to mimic meals, for many hours.
According to study co-author Matthew Webber, "this could work as a once-a-day injection for people with diabetes, helping them to achieve much better control of blood sugar..."