Figure 1.
Microfluidic chip for real-time electrical impedimetric monitoring of blood coagulation process.
(a) Illustration of the experimental setup. (b) Photograph of the microfluidic chip. The blood samples were loaded to the measurement wells respectively.
Figure 2.
Fabrication process of the microfluidic chip.
(a) Fabrication of the electrodes on glass substrate. (b) Fabrication of the PDMS wells. (c) Assembly of the microfluidic chip.
Figure 3.
Equivalent electrical model of the whole blood. Rp represents the plasma resistance.
Ri represents the red blood cell interior resistance. Cm represents the red blood cell membrane capacitance. CDL presents the double layer capacitance between the electrode and the electrolyte.
Figure 4.
Impedance spectrum (magnitude and phase angle) of the whole blood between 100 Hz to 10 kHz.
Blood sample in hematocrit of 45% was measured at 37°C. The solid line represents the impedance magnitude and the dash line represents the phase angle.
Figure 5.
Impedance spectrum of the whole blood and the blood clot.
The blood clot shows insulated, providing the impedance is high and the spectrum is fluctuated. Blood sample in hematocrit of 45% was measured at 37°C. The solid line and dash line represent the impedance spectrum of the whole blood and the blood clot, respectively.
Figure 6.
Blood coagulation process represented by the impedance magnitude at 1000 Hz.
The starting time of the blood coagulation is defined at the impedance magnitude which is 2 times the magnitude of the whole blood. Blood sample in hematocrit of 45% was measured at 37°C.
Figure 7.
Blood coagulation time under temperature variations of 18, 30, 37, and 50°C.
(a) Blood coagulation response under temperature variations. (b) Correlation between coagulation time and temperature. The impedance magnitude of the blood sample was measured at 1000 Hz. Blood sample in hematocrit of 45% was used. Error bars represent the standard deviations of three repeated measurements.
Figure 8.
Correlation between blood coagulation time and hematocrit of 30, 40, 45, and 50%.
The impedance magnitude of the blood sample was measured at 1000 Hz and 37°C. Error bars represent the standard deviations of three repeated measurements.