Scientists use nano technology to deliver insulin doses

by Barbara Hewitt on November 27, 2013

Nanotechnology could be the future for type 1 diabetics to regulate their blood sugar levels with a new technique that releases insulin under the skin.

It could give the freedom to release insulin painlessly using a small ultrasound device, allowing diabetics to go days between injections rather than using needles to give themselves multiple insulin injections each day.

The technique has been developed by researchers at North Carolina State University and the University of North Carolina at Chapel Hill. ‘This is hopefully a big step toward giving diabetics a more painless method of maintaining healthy blood sugar levels,’ said Dr. Zhen Gu, senior author of a paper on the research and an assistant professor in the joint biomedical engineering programme at the university.

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Patients can use a small, hand held device to apply ultrasound waves to the site of the nano network, painlessly releasing the insulin into the bloodstream

He explained that it involves injecting biocompatible and biodegradable nano particles into a patient’s skin. The nano particles are made out of poly(lactic-co-glycolic) acid (PLGA) and are filled with insulin.

Each of the PLGA nano particles is given either a positively charged coating made of chitosan, a biocompatible material normally found in shrimp shells, or a negatively charged coating made of alginate, a biocompatible material normally found in seaweed.

When the solution of coated nano particles is mixed together, the positively and negatively charged coatings are attracted to each other by electrostatic force to form a nano network. Once injected into the subcutaneous layer of the skin, that nano network holds the nano particles together and prevents them from dispersing throughout the body.

The coated PLGA nano particles are also porous. Once in the body, the insulin begins to diffuse from the nano particles. But the bulk of the insulin doesn’t stray far and is suspended in a de facto reservoir in the subcutaneous layer of the skin by the electrostatic force of the nano network. This essentially creates a dose of insulin that is simply waiting to be delivered into the bloodstream.

Using the new technology developed by Gu’s team, a diabetes patient doesn’t have to inject a dose of insulin as it is already there. Instead, patients can use a small, hand held device to apply focused ultrasound waves to the site of the nano network, painlessly releasing the insulin from its de facto reservoir into the bloodstream.

The researchers believe the technique works because the ultrasound waves excite microscopic gas bubbles in the tissue, temporarily disrupting the nano network in the subcutaneous layer of the skin. That disruption pushes the nano particles apart, relaxing the electrostatic force being exerted on the insulin in the reservoir. This allows the insulin to begin entering the bloodstream, a process that is made faster by the effect of the ultrasound waves pushing on the insulin.

‘We know this technique works, and we think this is how it works, but we are still trying to determine the precise details,’ said Dr. Yun Jing, an assistant professor of mechanical engineering at NC State and co-author of the paper.

Gu said the team has done proof of concept testing in laboratory mice with type 1 diabetes. ‘We found that this technique achieves a quick release of insulin into the bloodstream, and that the nano networks contain enough insulin to regulate blood glucose levels for up to 10 days,’ he pointed out.

He added that when the insulin runs out then the patient injects a new nano network. The previous nano network is dissolved and fully absorbed into the body in a few weeks.

‘This advance will certainly give millions of people with diabetes worldwide hope that better days are ahead. We must work to translate these exciting studies in the lab to clinical practice,’ said Dr. John Buse, director of UNC-Chapel Hill’s Diabetes Care Center.


The opinions expressed in this article do not necessarily reflect the views of the DiabetesForum.com Community and should not be interpreted as medical advice. Please see your doctor before making any changes to your diabetes management plan.

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