A microfluidic blood-clogging valve for on-chip blood analysis

The lack of simple but reliable microvalves is still a serious problem for many lab-on-a-chip applications. This work studied the use of blood coagulation, the transformation of liquid blood into solid coagulum, as a possible valving mechanism for microfluidic control and demonstrated a one-time open-to-close valve. This is done by creating a solidified blood coagulum, which clogs a normally-open fluidic channel as a closed valve. Local thermal coagulation is demonstrated using a focused laser for blood heating. This clogging valve can withstand a back pressure of 22 psig or higher and its simple structure is well-suited for disposable devices.