Smartphones for control and detection of rapid diagnostic tests

Abstract

This dissertation discloses smartphone audio-powered microfluidic technologies for flow control and detection in point-of-care rapid diagnostic tests. This work builds on the classic electric-hydraulic analogy and the concept of frequency-tuning to create, model, and characterize microfluidic equivalents of RLC electrical circuits with resonance in the audio range. These microfluidic resonant circuits were used to create novel microfluidic pump devices that provide both flow magnitude (on/off) and direction (forward/backward) control. The resonance frequency of microfluidic devices was most sensitive to the deformable part of the device that acts like a fluidic capacitor. By physically coupling this elastic capacitor to a clotting sample of plasma, enzymes essential to inducing elasticity to the blood clot, like fibrin cross-linking activator FXIIIa, can be functionally detected as resonance frequency shifts from the decreased total capacitance. Since flow control and analyte detection – two core components of a rapid diagnostic test – occurs in the audio frequency range, this microfluidic technology is well-suited to be paired with any audio device, like a smartphone, to serve as a replacement for the instrumentation commonly required in disease testing.