The Walt Lab pioneered the use of microwell arrays for single-molecule detection and analysis, which has revolutionized the process of genetic and proteomic sequencing, enabling the cost of DNA sequencing and genotyping to plummet nearly a millionfold in the last decade. This technology is now the gold standard for sequencing in a wide variety of applications including screening embryos for genetic defects before in vitro fertilization, studying disease in preserved/frozen tissues, improving crop disease resistance, and identifying individuals’ metabolic profiles to ensure proper drug dosage. The current research employs optical fiber microarrays for the detection and analysis of single enzyme molecules to provide mechanistic insight into enzyme mechanisms. Based on this technology, the Walt lab has developed a technique known as Single Molecule Arrays (Simoa) for ultra-sensitive detection of analytes such as proteins and microRNAs. Using Simoa, the Walt lab is currently developing blood-based tests for various diseases including breast cancer, Parkinson’s, and Tuberculosis. In another project, the Walt Lab is investigating the limits of creating high-density sensing arrays containing thousands of microsensors and nanosensors, and are preparing arrays to perform high-density nucleic acid and protein analysis. Another application of this effort is an integrated diagnostic platform for performing medical diagnostics using saliva as a sample instead of blood. The arrays can also be used to study living cells, both as cell populations and as individual cells, and analyze the contents of individual cells by integrating microfluidics with single-molecule detection. They are also studying the behavior of large numbers of cells to understand the distribution of cell behaviors in a population.