THERMAL ANALYSIS OF A MODULAR, MICROFLUIDIC DEVICE FOR THE RAPID DETECTION OF STROKE

A modular, microfluidic device was designed to aid in the rapid detection and treatment of stroke. The device modules process whole blood for the detection of genes expressed in response to a stroke event using a series of assay steps including: cell capture using antibodies, thermal lysis, solid-phase reversible immobilization (SPRI) of nucleic acids, reverse transcription (RT), ligase detection reaction (LDR), and single pair fluorescence resonance energy transfer (spFRET) readout. Cell lysis, RI, and LDR require temperatures of 90 degrees C, 37 degrees C, 65 degrees C and 95 degrees C respectively, therefore strict thermal isolation constraints between thermal zones in the device modules were necessary. Thermal isolation was accomplished using 2 mm and 1 mm air gaps between the fluidic modules and heating elements in the polymer device. Finite element mathematical models (ANSYS v. 12.1, Houston, PA) were used to characterize the thermal zones in two 2D simulations. Section 1 simulation results showed +/- 1.5 degrees C in cell lysis, +/- 1.6 degrees C in RT, and +/- 1.6 degrees C in the denaturation section of LDR. Section 2 simulation showed +/- 2.6 degrees C in denaturation and +/- 0.4 degrees C in the annealing/extension zone of LDR.