Insulin that "feels" blood sugar – type 1 diabetes solution?

7:00 am – wake up and check blood sugar. 9:00 am – eat breakfast, calculate carbohydrates, check blood sugar. 11:30 am – eat lunch and take insulin. 1:00 pm – eat a snack, calculate carbohydrates, take insulin. Repeat steps every 1-2 hours, depending on blood sugar levels.

This is what a typical day in the life of approximately 9 million people with type 1 diabetes (T1D) can look like. 

"With type 1 you have to think about every decision you make, right from the moment you wake up," says Grace Bennett, who works for the type 1 diabetes charity Breakthrough T1D. 

Grace was diagnosed with type 1 diabetes when she was 12.

"If I want to eat a snack, I have to ask myself if I want a snack badly enough, is my blood sugar at a point where I really should be having a snack, am I eating it because I am hungry?," says Grace.

The bodies of people with type 1 diabetes can't produce their own insulin, so they must regularly dose themselves with a synthetic version of the hormone. Living with the daily demands of T1D includes closely monitoring blood sugar and carefully regulating insulin doses.

But what if a single injection of insulin just once a week were enough? Or if the insulin formulation itself could "feel" levels of blood sugar, making hourly checks a thing of the past? 

Six new research projects in universities in the US, China and Australia are trying to achieve this as researchers develop newer and "smarter" insulins.

What is type 1 diabetes?

Sugar in the blood, also called blood glucose, is the primary source of energy for the body. 

When you eat food, the body breaks down most of it into glucose, which is released into the bloodstream. When glucose levels go up, the pancreas releases the hormone insulin. It helps glucose to be used as energy by your cells.

In people with type 1 diabetes, the pancreas either can't produce insulin or produces very little of it. No or low insulin prevents the uptake of glucose in the body's cells, causing it to build up in the bloodstream. 

High levels of glucose in the blood are dangerous. If left untreated, they can lead to heart disease, kidney problems, extreme fatigue and other serious conditions. 

In 2019, diabetes was the direct cause of 1.5 million deaths globally.

"You have this thing that runs essentially your entire life. At the same time, it's also a largely invisible illness, unless you see my insulin pump or my continuous glucose monitor," says Grace.

Why do we need better insulins?

Glucose levels in the blood change constantly. They go up and down depending on your stress levels, whether you have exercised, what foods you have eaten, and levels of other hormones in your body. Even the weather can affect them. 

"Insulin-wise, food-wise, exercise-wise, I can be doing things the exact same way as I did the day before. But my blood sugars might look vastly different, depending on hormones or exercise. It's not something you can ever not be thinking about," says Grace.

This makes it very hard for the bodies of people with type 1 diabetes to maintain stable levels of blood sugar, even with the newest technology available to monitor glucose and administer insulin when needed.

"There have been times where I've had to say to myself that I literally don't have an option. There is no 'Oh, I'll skip my medicine because I don't like the way it makes me feel' or 'I need a day off'. That's gonna end in an ER visit and possibly worse," says Grace.

What could "smart insulins" look like?

Glucose-responsive insulins (or smart insulins) promise an end to the constant glucose monitoring that can be so burdensome for many people with T1D.

Instead, they could take a pill or inject insulin once a day in the morning that remains inactive in the body until blood sugar levels rise. 

Once the smart insulin detects a change in glucose levels, it can "wake up" and stabilize them before returning to an inactive state again.

The effect would be similar to that produced by a functioning pancreas, which only releases insulin when it's needed in the body. 

For Grace, the possibility of using glucose-responsive insulins not only would impact the physical aspect of T1D, but ease out the mental burden that comes with daily routine.

"If I knew I was using an insulin that could sense what my blood sugar was and respond, that is less time that I have to think about what I'm doing. I could, for example, go for a walk around the block without having a packet of honey with me just in case I go low," says Grace.

Are we there yet?

Although research on smart insulins is still in its early stages, the hope is that one day they can take the pressure off people who currently have to monitor their blood glucose levels multiple times a day.

The Type 1 Diabetes Grand Challenge is funding six projects involving universities from the United States, China and Australia with more than €3 million (£2.7 million) to develop novel insulins. 

One of the projects at Stanford University in the US aims to develop an ultra-fast insulin which gets released more quickly in the bloodstream, mimicking a type of insulin cone snails use to immobilize prey. 

Another project from Zhejiang University in China hopes to reduce insulin injections to once a week by fine-tuning how the hormone is released from a reservoir in the body.

"If you told 12-year-old me that one day they would be researching insulins that might have the capability to behave like this in the human body, I'd be like 'No way, that's insane'. The progress that's been made in researching these novel insulins or management tools is truly incredible," Grace adds.