Key facts:
- Millions are already taking tablets containing heparin to reduce the risk of clots
- The new patch automatically injects the same drug through miniature needles
- This prevents patients from taking too much, which can cause fatal bleeding
A high-tech skin patch could prevent deadly blood clots that cause strokes and heart attacks. The patch detects when a clot is in danger of developing and automatically releases a blood thinner into the bloodstream in time to halt it.
How it works?
It is done through micro-needles in the patch which gently pierces tiny blood vessels called capillaries just beneath the skin. The needles thinner than the strands of hair, monitors thrombin levels as blood passes by and detects when it is becoming riskily thick and prone to clotting.
If thrombin levels are abnormally high, tiny amounts of heparin are released into the blood reducing the clot formation risk. Heparin works by ‘turbocharging’ the body’s own blood-thinning molecule, called antithrombin III, making it up to 2,000 times more effective.
Anticoagulants necessity:
Millions of people in Britain take heparin tablets daily to reduce the risk of clots, thrombosis. Some people are prescribed for Atrial fibrillation, an irregular heartbeat that causes blood stasis, increasing the chances of a clot breaking away and travelling to the brain-causing stroke. Others take the drug because they already have stroke and are at high risk of developing another.
Patients who had undergone major surgeries like- hip or knee replacement are also put on short courses of heparin tablets or injections as immobility puts them at higher risk of blood pooling and formation of clots.
Patients on anticoagulants like heparin require blood tests to ensure they are receiving the exact dose. Too much medicine can cause fatal bleeding, because blood is too thin to clot. Too little can cause lethal clot.
The High-tech patch:
The postage stamp-sized patch, developed at North Carolina State University, keeps a round-the-clock check on thrombin levels and so does away with the need for repeated blood tests. On one side it is covered in more than 100 miniature plastic needles. These are covered in a coating containing liquid heparin and a special chemical containing amino acids that binds the drug to the surface of the needles.
Mechanism of the patch:
When thrombin levels are elevated, a chemical reaction takes places within the amino acid coating- and releases heparin into the blood. So far, the disposable patch, which can be changed daily, has only been tested on mice.
Scientists injected them with large amounts of thrombin- enough to cause a fatal blood clot- after applying the patch or a heparin jab.
The results published last month in the Journal of Advanced Materials, showed all the mice with the patch survived but 80% of those on a heparin injection died from the results of a clot.
Researchers suggest the patch has far better results compared to oral ingestion of heparin and is now planning to test the patch on patients. Professor Martin Cowie, a professor of cardiology at Imperial College London, says the smart patch could improve anticoagulation for patients at risk of clots. The concept of a self-regulating patch that tailors the release of a drug as needed into the body is very innovative. It’s well worth pursuing,’ he adds.
Professor Jeremy Pearson, an associate medical director at the British Heart Foundation, believes that the patch is ‘an ingenious approach’.
The initial results in mice shows promising results and would have advantages in human anticoagulation therapy over the current treatment which requires repeated injections of heparin.