Rapid and Nondestructive Evaluation of Platelet Function in Whole Blood by Microfluidic Deterministic Cytometry

Platelet size is a determinant of platelet function. Here, a new microfluidic deterministic cytometry packed with S-shaped micropillars (S-MDC) was developed to rapidly and sensitively determine the apparent size (D_app) of platelets, which was used to evaluate platelet function. The platelet D_app in the diluted whole blood was rapidly and label-freely measured by S-MDC within 2 min under shear rates (0.4 mm/s) that mimicked physiological conditions. The level of CD62p on platelets scarcely changed before and after platelets went through the whole S-MDC, indicating that the platelet function was nondestructive. Notably, the human platelet D_app determined before and after thrombin addition by S-MDC was highly coincident with the levels of CD62p on the platelet surface by flow cytometry (r = 0.819), revealing that the human platelet D_app was available to assess the platelet activation state. In addition, the results of the rat platelet D_app were consistent with myocardial injury of rats with myocardial ischemia before and after treatment with antiplatelet agents, suggesting that rat platelet D_app can be used to reflect myocardial injury in vivo outcomes. These findings reveal that S-MDC is a promising technique for screening tests for a bleeding disorder, in addition to monitoring antiplatelet drugs.