Leveraging Microfluidics and Electrokinetics to Improve Sample Preparation and Biomarker Detection.

다국어 초록 (Multilingual Abstract)

With the advent of global pandemics, the world has developed a demonstrable need for rapid and low-cost testing platforms for diagnostics. Microfluidic diagnostics can meet this demand due to the versatility and scalability of microfluidic devices. However, two components of microfluidic diagnostics, sample preparation and biomarker detection, require further innovation for effective use within microfluidics. In this work, improvements to microfluidic sample preparation and biomarker detection are presented. To improve microfluidic sample preparation, the leading electrolyte (LE) in free-flow isotachophoresis (FFITP) was replaced with a conductive wall, limiting system complexity and analyte-electrolyte interactions. This new system, called free-flow teichophoresis (FFTPE), was used to concentrate protein, separate multiple proteins, and concentrate nucleic acids. To improve microfluidic biomarker detection, a novel heating method called Electrokinetic Nucleic Acid Amplification (E-NAAMP) was developed. E-NAAMP replaces traditional boundary-driven heating techniques found in microfluidic nucleic acid amplification (NAA) by applying electric current directly to the reaction. E-NAAMP was used to drive NAA using both Loop-Mediated Isothermal Amplification (LAMP) and the Polymerase Chain Reaction (PCR). Finally, improvements were made to E-NAAMP by incorporating it into a novel paper microfluidic platform called Microfluidic Pressure-in-Paper (μPiP). Paper E-NAAMP was used to amplify nucleic acids with LAMP. It was also demonstrated that paper passivation via a carrier protein is necessary for paper E-NAAMP success. With these improvements, we envision an all-in-one chip where FFTPE is used to remove NAA inhibitors from biological samples and E-NAAMP is subsequently used to amplify these inhibitor-free nucleic acid samples.