MICROFLUIDIC DEVICE AND METHODS FOR DIGITAL ASSAYS IN BIOLOGICAL ANALYSES

摘要

An electrowetting on dielectric (EWOD) device and a related method of performing a digital biological assay in an EWOD device are described. The method includes the steps of: inputting a sample reservoir containing biological entities and assay reagents into the EWOD device; partitioning the sample reservoir into partitions for the biological assay by performing electrowetting operations with the EWOD device; measuring a volume of each partition; changing a condition of the partitions to initiate the biological assay, wherein the changed condition results in the biological entities performing a biological process to generate a product substance; and performing the biological assay by the steps of: measuring a partition property and a volume of each partition in real time, wherein the partition property is indicative of the product substance generated by the biological process of any biological entity or entities within a respective partition; determining a concentration of the product substance in each partition based on the measured partition property and volume; and categorizing the partitions by a number of biological entities contained in each partition based on the determined concentration of the product substance. Based on such categorization, the number of biological entities may be calculated, which in turn may be used to calculate the total number of biological entities or concentration in the sample reservoir. The method further may include an enhanced partitioning process that minimizes variation in the volume of the partitions.