Measuring micro-interactions between coagulating red blood cells using optical tweezers

Agents that alter the dynamics of hemostasis form an important part in management of conditions such as atherosclerosis, cerebrovascular disease, and bleeding diatheses. In this study, we explored the effects of heparin and tranexamic acid on the efficiency of blood coagulation. Using optical tweezers, we evaluated the pN-range micro-interaction between coagulating red blood cells (RBCs) by measuring the minimum power required to trap them. By observing the mobility of RBCs and the intensity of cellular interactions, we found that the coagulation process can be separated into three phases. The effects of heparin and tranexamic acid were examined by observing variations in cellular interaction during the coagulation phases. Heparin attenuated the interaction between RBCs and prolonged the first phase whereas the samples containing tranexamic acid bypassed the first two phases and immediately proceeded to the final one.