Experts from US hospitals and institutions including Harvard University managed to transplant cells into mice, which immediately began producing insulin.
The team was also able to show they could prevent the cells being rendered useless by the body’s own immune system, which was effectively “switched off” thanks to scientific work.
It means a cure for Type 1 diabetes – which affects 400,000 people in the UK – could be much closer. Scientists are now working to replicate the results in people with the condition.
The findings build on the news at the end of 2014 that experts had discovered how to make huge quantities of insulin-producing cells.
The man who led that breakthrough – Harvard professor Doug Melton who has been trying to find a cure for the disease since his son Sam was diagnosed with Type 1 diabetes as a baby – also worked on the new studies.
The human islet cells used for the new research were generated from stem cells developed by Prof Melton.
Following implantation in mice, the cells immediately began producing insulin in response to blood glucose levels and were able to maintain blood glucose within a healthy range for 174 days.
The findings are published in the journals Nature Medicine and Nature Biotechnology and were made possible with funding from the Juvenile Diabetes Research Foundation (JDRF).
In one study, experts were able to create a newly-modified alginate material to encapsulate human pancreatic islet cells – a way of making the body adopt them.
The modified alginate, a material originally derived from brown algae, was used to prevent the body triggering an immune response which can lead to the build-up of scar tissue and the cells ultimately being rendered useless.
Scientists created a library of almost 800 alginate derivatives and evaluated the immune response to each of them. This led them to focus on one called triazole-thiomorpholine dioxide (TMTD), which had a minimal immune response in mice and large animals.
The researchers then implanted human islet cells encapsulated in TMTD in mice, which provided the success for the study.
Sarah Johnson, UK director of policy and communication at JDRF, said: “It’s significant to see a study of this length return such promising results.”