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Auto-Antithrombotic Patch: Intelligent Subcutaneous Drug Delivery and Drug Release

2016-11-29 来源:亚科官网
29 November 2016
   Last week, an article entitled "Thrombin-Responsive Transcutaneous Patch for Auto-Anticoagulant Regulation"[1] was published by <Advanced Materials>, a leading academic journal in the field of materials science, researchers from the University of North Carolina at Chapel Hill and North Carolina State University developed an intelligent polymer antithrombotic patch that provides a new strategy for the prevention and treatment of thrombosis.
advanced materials
   Thrombosis is a blood clot that occurs in the circulating blood, or blood deposits on the walls of the heart or blood vessels, due to some inducements of the human or animal during their survival. These deposits can block the body's normal blood circulation, leading to pulmonary embolism, heart disease or stroke and a series of serious consequences. According to statistics, China has the largest number of thrombosis incidence; in the United States, 100-300 thousand people died of venous thrombosis every year, the relevant hospitalization is more than 500 thousand.
   There are many clinical antithrombotic drugs, in general, it can be divided into two types——antiplatelet drugs and anticoagulants. The common antiplatelet agents are aspirin (acetylsalicylic acid), clopidogrel (2-thiophene ethylamine and 2-thiophene ethanol), Tigreilo, cilostazol. The common anticoagulants are heparin, low molecular weight heparin and warfarin, dabigatran etexilate, rivaroxaban, apixaban and so on. Although these drugs are effective, they are very cumbersome in the actual use of the process. The purpose of anti-thrombosis could not be achieved if the patients take less than need, if more are taked, there will be the risk of bleeding. To ensure the amount of drugs in the appropriate range, the patients need to test coagulation function regularly. 
  The researchers developed a system that reacts to thrombin: heparin is added to the system, when thrombin is activated, the system could cut off the specific polypeptide chain, release heparin. In recent years, the team has pioneered the idea of a biologically responsive transdermal microneedle patch that delivers dose-controlled, intelligent subcutaneous delivery: it automatically releases the drug when the patient needs it. It will be a self-regulation system with the physiological signal response. They have developed intelligent insulin patch, islet cell patch, and patches that can respond to the tumor microenvironment with antibodies to the immune checkpoint (PD-1/CTLA4).
microneedles
  Researchers have created a patch of "microneedles", consisting of hyaluronic acid polymers that are attached to heparin by a specific polypeptide chain. Researchers hope that these polymers can release of heparin after they are exposed to thrombin in the blood. The more thrombin in the blood, the more heparin required to reduce the risk of coagulation. This disposable patch will release more heparin with the increase of thrombin in blood.
Auto-Antithrombotic Patch
  To test the difference between this patch and heparin injections, the researchers conducted two trials: Tests for short-term prevention and long-term prevention.
Short-term prevention:
   In this study, mice in the experimental group received either heparin or a smart patch; the control mice did not use any effective prophylactic means. Ten minutes after the prophylactic treatment, these mice received a thrombogenic injection sufficient to kill. However, only mice in the control group died, and mice in the experimental group survived.
  This result shows that there is no significant difference between smart patch and heparin injection in the short-term ability to prevent thrombosis.
Long-term prevention:
  A lethal dose of thrombin was injected into the mice 6 hours after heparin or smart patch. In just 15 minutes, mice that received only heparin had a mortality rate of 80%, whereas mice using the smart patch were asymptomatic.
  This result shows that, the smart chip is better than ordinary heparin injection in the long-term prevention effect.
  These results are expected to lead to a self-regulating closed-circuit smart patch, the more accurate while reducing the cost of treatment. Researchers are now trying to further increase the amount of drug loading in the patch, making the drug content can be adjusted according to the different needs of each patient, more pre-clinical trials are expected in the near future. The early transformation of this smart patch will benefit more patients living in the risk of thrombosis.
References
[1] Yuqi Zhang, Jicheng Yu, Jinqiang Wang, et al. Thrombin-Responsive Transcutaneous Patch for Auto-Anticoagulant Regulation. Advanced Materials 2016, doi: 10.1002 / adma.201604043.
Related links: 2-thiophene ethylamine
                      
2-thiopheneethanol
                      
Acetylsalicylic acid
Edited by the Editorial Office of Suzhou Yacoo Science Co., Ltd.