A patch for the prevention of thrombosis
An international team of researchers working at North Carolina State University and the University of North Carolina at Chapel Hill has created a "smart patch" that monitors the patient's blood condition and releases a blood-thinning drug to prevent the formation of life-threatening blood clots and subsequent vascular thrombosis.
Thrombosis develops in cases when blood clots disrupt normal blood flow in the body, which can lead to serious medical problems such as pulmonary embolism, heart attack or stroke. Modern methods of thrombosis therapy are based on the use of blood-thinning drugs, such as heparin, the selection of adequate doses of which requires regular blood tests. Too high dosages can cause problems such as spontaneous bleeding, while too low doses may not provide protection against recurrence of thrombosis.
The aim of the authors' work was to create a system that allows continuous monitoring of the state of the blood coagulation system and, if necessary, to release an additional dose of the drug into the bloodstream.
The patch they developed is covered with microneedles made of a polymer containing hyaluronic acid and the anticoagulant heparin. The polymer is modified in such a way as to respond to an increase in the concentration of thrombin, an enzyme that initiates the process of blood clotting.
When the concentration of thrombin in the blood increases, it destroys the specific amino acid chains that bind hyaluronic acid and heparin, releasing heparin into the bloodstream. At the same time, the higher the concentration of thrombin, the more heparin is released into the patient's blood.
Schematic image of a patch releasing heparin in contact with thrombin
The authors tested their "smart patch" on a mouse model. During the experiments, animals were injected with large doses of thrombin, which, without adequate therapy, would cause fatal pulmonary vascular thrombosis.
In the first experiment, the animals were divided into three groups: mice of one group were injected with heparin, mice of the second group were glued with an experimental patch, and animals of the control group were not subjected to interventions. 10 minutes after the intervention, all animals were injected with a potentially lethal dose of thrombin. 15 minutes after that, all the animals of the control group died, while the animals of the other two groups remained alive.
In the second experiment, thrombin was administered 6 hours after heparin administration and patch application. About 80% of the mice who received the heparin injection died 15 minutes after the introduction of thrombin, while all the animals with the experimental patch remained alive.
The authors are very inspired by the results of their work, as the self-regulating patch they created is able to help a huge number of people and at the same time significantly reduce the cost of thrombosis therapy. Currently, they are working on increasing the capacity of the patch, as well as on methods of regulating it depending on the individual needs of the patient.
Article by Yuqi Zhang et al. Thrombin-Responsive Transcutaneous Patch for Auto-Anticoagulant Regulation is published in the journal Advanced Materials.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru Based on materials from NC State University: Smart Patch Releases Blood Thinners As Needed, Prevents Thrombosis in Animal Model.
02.12.2016