Many people have heart attacks and strokes, because they are prone to forming blood clots. Deep vein thrombosis and pulmonary embolism are also caused by blood clots. Aspirin and Coumadin are two widely used drugs to prevent inappropriate formation of blood clots. Aspirin works by preventing platelets from sticking together and Coumadin works by inhibiting vitamin K-dependent clotting factor activation. Both these drugs can have serious side effects. A study in the online scientific journal ACS Nano found that injection of nano silver particles into mice prevented platelets from sticking together without causing side effects.
Without blood clotting, we would all bleed to death following an injury. An injury activates blood platelets and causes them to become sticky. They aggregate and help form the blood clot. Unfortunately, blood clots often form in blood vessels for unknown reasons, break loose, travel and block the blood supply to critical organs. Atherosclerotic plagues in arteries also activate the clotting mechanism and make platelets sticky.
Researchers found that mice, prone to blood platelet aggregation, when treated with nano silver, kept platelets from being activated. The nano particles prevented the platelets from sticking together and forming clots. The anti-sticking effect could be seen both in a Petri dish and in the blood of live animals. Nano silver was far more effective in these experiments than any other drug directed at stopping platelet aggregation.
Colloidal silver is a solution of suspended particles with sizes ranging from 1-1000 nanometers. It has been used historically to disinfect and treat infections. It is still used for these purposes in many developing countries and in alternative medicine. You can buy colloidal silver in health food stores. Wound dressing with impregnated silver are still used in medical procedures today. Numerous medical devices also incorporate silver for its antiseptic properties.
Silver is toxic for bacteria, algae and fungi, but relatively non-toxic for humans. However, serious side effects like argyria occur with ingestion of high concentrations of colloidal silver. Argyria manifests itself as a permanent blue/gray coloration of skin. Other reported side effects are seizures, kidney damage and stomach distress.
There is great variation in concentration, particle size and additives in solutions of colloidal silver. Before nano silver particles can be used as an alternative to anti-clotting or anti-platelet drugs, studies need to determine at what concentrations they are safe and non-toxic for people. Another critical question is: Will these silver particles interfere with normal blood clotting? Although nano silver particles were safe and effective in mice, human studies are needed.
Shrivastava S. Characterization of antiplatelet properties of silver nanoparticles. ACSNano (2009) 3, 1357