Cutting-edge research in biomechanics led by UCR Professor of Mathematics Mark Alber and researcher Oleg Kim, along with the School of Medicine at the University of Pennsylvania, are leading advancements in stroke and heart attack treatments. Heart attacks and strokes are mainly caused by blocked blood pathways from the heart to the brain. This new approach studies blood clotting with relation to the physical movement of blood platelets.

Blood clotting plays a major role in the prevention or induction of blood flow. One of the crucial aspects of blood clotting is finding a happy medium, or homeostasis, between not clotting

enough, leading to internal bleeding, and clotting too much and blocking blood flow. So far, scientists have a good understanding about how and why blood clots form, but very little is known about how they regulate themselves in perfect sizes to maintain a good blood flow.

Mark Alber, a distinguished professor of mathematics at UCR, along with the rest of the intercollegial research team are using biomechanics, advanced bioimaging techniques and physics to run time lapses of blood clotting to figure out exactly how blood clots begin and contract when they are no longer needed.

Blood clots form as a result of hormonal response in the blood stream as sticky blood platelets are released to fill in the gap between the torn blood vessels, which are made out of muscles and consists of fibrin chains (fibers) and filaments that hold each other together. A unique feature of the fibrin chains is their flexibility. According to the recent discoveries of this study, the platelets appear to pull the fibers and filaments together while the platelets themselves contract and shrink, allowing for regular blood flow.

Alber and his colleagues are using high-end bio imaging techniques to visualize how the filaments and blood clots move. Some methods include high-resolution confocal microscopy and rheometry (using contrast images and time lapse techniques combined) to output three-dimensional dynamic structural and mechanical measurements of the platelet-fibrin meshwork over the course of clot contraction in a short movie animation.

By analyzing each step of the clot contraction and shrinking process, Alber and his team are able to detect the physical changes the fibrin and the platelets undergo as the platelets clearly pull on the fibrin while slowly coiling around themselves and shrinking to eventually detach into the bloodstream. This process, however, is done in series as multiple platelets work at the same time to achieve recovery in an efficient time.

This research has made a crucial discovery about the structural mechanism by which local platelet-fibrin interactions result in dramatic modifications of the whole clot architecture. Results clearly prove that platelets bend and shorten fibrin fibers while they themselves shrink as the fibers come closer to each other and attach maintaining regular blood flow. This research opens great doors into the future to prevent many blood clotting disorders and other serious medical issues.