IIT-M researchers develop technique to accurately measure blood clotting time; of use to manufacturers making implants Premium

IIT Madras researchers patent a technique to measure blood clotting time, enhancing implant safety and water purity testing.

Researchers at IIT Madras have secured a patent for a technique that uses changes in reflected light on the surface of implants, to detect blood clot formation. While it will allow manufacturers to use this technique while researching the viability of materials to be made into implants, it also has applications in real world issues such as testing water purity, they claim.

Haemocompatibility is the ability of a material or medical device to interface with blood without inducing some adverse reactions, including clotting. It remains an important parameter to be considered before developing any material to fashion a device, including stents, heart valves and catheters, that will come into contact with blood.

The haemocompatibility test also helps to plan for and titrate the dose of anti-coagulation medicine to be given to the patient, post surgery. This is where researchers at IIT Madras have stepped in, to offer an optics-based solution to improve the accuracy of this test. Subhashree Mishra, Govinda Chandra Behera, Vignesh Muthuvijayan and Somnath Chanda Roy describes the technique in an article published in the journal Review of Scientific Instruments.

“When blood comes into contact with a foreign material (as used in implants) it begins to clot. When we plan to build implants, we need to check how much time blood is taking to clot over the foreign device. Despite several technological advancements in biomedical devices, issues related to thrombosis remain a persistent challenge,” explains Ms. Mishra. The two techniques are used today, she says -- mechanical tilting method, and free haemoglobin method — are not precise.

“We set out to address the shortcomings of the conventional techniques to measure blood clotting,” she further says. Researchers used the optics to measure this blood clotting time. “The surface of any implantable device will have a reflective surface. When blood touches this surface, and the blood clotting process begins, the surface becomes turbid, and the reflectivity of the surface will change. When it does, it will trigger a change in voltage in a connected, highly sensitive photodetector. The time taken for this “voltage change” corresponds to clotting time, Ms. Mishra says. The results, from our study, were accurate; and even milliseconds are counted,” she adds.

“We have received the patent for this technique, last year,” says Somnath Chanda Roy, professor, department of Physics, IIT Madras. We are at the initial stage of discussions with manufacturers – this will enable them to quantitatively screen materials for blood compatibility at the research stage. It can help them distinguish between materials that may be similar but behave very different during clot formation, and has the potential to significantly reduce clot-related risks for patients, he adds.