Microfluidic platelet function analyzer for shear-induced platelet activation studies

Platelet function is suggestive of pathological conditions in heart related diseases. With current insufficient prognostic devices, we see the need for a device to assess complete platelet function. This work presents our preliminary microfluidic device for the analysis of shear-induced platelet activation, which is crucial in studying the pathological role of platelets. In our novel device, the polydimethylsiloxane microchannels were coated using a novel layer-by-layer self-assembly technique to provide controlled nanometer-thick layers of fibrinogen. Anticoagulated platelet rich plasma labeled with a fluorescin isothiocynate-tagged anti-GpIIb/IIIa-antibody was passed through these microchannels and several experimental runs for different shear rates were carried out. Finally, fluorescence assays confirmed the activation of platelets in the microchannels for various shear rates. Control experiments showed that the extent of adhesion on bare PDMS surfaces was less than on the surfaces assembled with fibrinogen. Based on image processing, the extent of platelet adhesion to the fibrinogen substrate was determined for each of the shear rates. The extent of adhesion (phi) was modeled as a third order polynomial in shear rate for substrate fibrinogen.