 One of the most critical factors in the fight against diseases such as cancer is the development of early stage detection methods. Cells, including tumor cells, regularly excrete nanoscopic particles called exosomes that contain molecular information from their cell of origin. Abundant in blood and other body fluids, these tiny vesicles are about 100 times smaller than a red blood cell, making them difficult to separate using traditional technologies. IBM has developed a chip-based technology called NanoDLD for automated size separation and purification of exosomes. Exosomes enter the NanoDLD pillar array and are split into separate streams according to size. How? The pillar geometry splits the exosome-carrying fluid into streams. Smaller particles can stay within a single fluid stream, zigzagging around pillars. While larger particles cannot fit within a single stream and are deflected, separating them from the smaller particles. Separated exosomes are collected and analyzed for biomarkers of diseases such as cancer. On-chip exosome separation opens the door for less invasive monitoring of early stage disease and treatment efficacy.