This lecture covers the capillary flow progression in paper microfluidics, discussing the equilibrium between capillary force and flow resistance force, the differential equation governing the liquid front progression, lateral flow assays formats, and the principles of lateral flow assays for SARS-Cov-2 detection. It also explores the use of gold nanoparticles in bioassays, automated LFA readers, evaluation of test results accuracy, and the application of paper microfluidics in controlling flow progression.