MicroRNAs (miRNAs) are small RNA molecules that regulate the expression (activation) of genes. Recent studies of miRNA expression implicate these molecules in early development, brain development, cell proliferation and cell death. They are also implicated in disease states, such as chronic lymphocytic leukemia. Determining how, when, and where miRNAs are produced and function in cells and tissues would have profound impact on medical disciplines ranging from embryology to cancer diagnosis and therapy. The genes expressed in miRNA differ between developing and mature tissues, and comparing normal tissues to tumour tissues also reveals different miRNA expression profiles. Further studies looking at differentially expressed miRNAs could help identify those miRNAs involved in human cancer development. Unfortunately, traditional expression profiling techniques are laborious, costly, slow, or lack the sensitivity to effectively screen populations of cells and quantify miRNA content. A promising approach to overcome these limitations is the use of microfluidics technology. This technology involves constructing small chips with thousands of fluid-filled chambers, which can each contain a single cell. This reduces the number of cells used and the cost of each experiment, and allows thousands of experiments to be performed on a single chip simultaneously. Adam White is developing a microfluidic device capable of inexpensive miRNA expression profiling of many single cells at the same time. Upon successful development of this new microfluidic tool, he will work with other scientists to look for differentially expressed miRNAs in blood related cancers such as acute myeloid leukemia. The development of a microfluidic device for single cell analysis of miRNA would greatly accelerate the identification of those miRNAs involved in cancer development, and ultimately improve methods of cancer diagnosis and treatment.