Coagulation
monitoring is essential for perioperative care and
thrombosis treatment. However, existing assays for coagulation monitoring
have limitations such as a large footprint and complex setup. In this
work, we developed a miniaturized device for point-of-care blood coagulation
testing by measuring dynamic clot retraction force development during
blood clotting. In this device, a blood drop was localized between
a protrusion and a flexible force-sensing beam to measure clot retraction
force. The beam was featured with micropillar arrays to assist the
deposition of carbon nanotube films, which served as a strain sensor
to achieve label-free electrical readout of clot retraction force
in real time. We characterized mechanical and electrical properties
of the force-sensing beam and optimized its design. We further demonstrated
that this blood coagulation monitoring device could obtain results
that were consistent with those using an imaging method and that the
device was capable of differentiating blood samples with different
coagulation profiles. Owing to its low fabrication cost, small size,
and low consumption of blood samples, the blood coagulation testing
device using carbon nanotube strain sensors holds great potential
as a point-of-care tool for future coagulation monitoring
