IIT-M researchers are developing a technology to accurately measure blood clotting time; For use by manufacturers who make implants

Researchers at IIT Madras have patented a technology that uses changes in light reflected on the surface of implants to detect blood clot formation. While it will allow manufacturers to use this technology 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.

Improving thrombotic testing

Hemocompatibility is the ability of a substance or medical device to interact with the blood without causing some harmful reaction, including clotting. This remains an important criterion to consider before developing any material for a device design, including stents, heart valves and catheters, that will come into contact with blood.

Hemocompatibility testing also helps in planning and titrating the dose of anticoagulant medication that will be given to the patient after 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 describe this 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 starts to clot. When we plan to build implants, we need to check the amount of time it takes for the blood to clot over the foreign device. Despite many technological advances in biomedical devices, issues related to blood clotting remain an ongoing challenge,” explains Ms. Mishra. She says that the two methods used today – the mechanical tilt method and the free hemoglobin method – are not accurate.

“We set out to address the shortcomings of traditional techniques for measuring blood clotting,” she also says. The researchers used optics to measure blood clotting time. “The surface of any implantable device will have a reflective surface. When blood touches that surface, and the blood clotting process begins, the surface will become turbid, and the reflectivity of the surface will change. When that happens, it will trigger a voltage change in a connected, very sensitive photodetector. The time taken for this ‘voltage change’ corresponds to the clotting time. The results, from our study, were accurate, and are calculated even to the millisecond,” says Ms. Mishra.

Potential wider applications

“We patented this technology last year,” says Somnath Chanda Roy, professor of the Department of Physics at the Indian Institute of Technology Madras. We are in the first phase of discussions with manufacturers – this will enable them to quantitatively screen the material for blood compatibility in the research phase. He adds that it can help them distinguish between substances that may be similar but behave very differently during clot formation, and has the potential to significantly reduce clot-related risks for patients.

The team is also looking to deploy this technology in other real-world applications, says Professor Roy, primarily to measure water purity. “With the substrate, and some changes, it will be able to check for even small impurities in the water. There will be obvious industrial uses for this as well.”