Compact 3D-printed z-positioning unit for high-throughput microscopy

Modern day biomedical research requires analysis of a considerable number of cell populations. Frequent observation of each sample is essential to determine e.g. growth characteristics of the cells. Automated high-throughput microscopes offer the ability to scan large numbers of samples in short periods of time. In order to get in-focus images of the sample, precise and fast positioning along the z-axis is needed. The availability of such automated microscopes, however, is limited due to high acquisition costs, resulting in tightly scheduled utilization. In this paper, a compact and inexpensive High-Throughput Microscope, using a monolithic lever mechanism for precise z-positioning, is presented. Multiple microscope elements are positioned along the z-axis in open loop control with a step-width of 10 micrometer and an overall displacement of 2 mm. Providing a reasonable trade-off between cost and positioning accuracy, the presented z-positioning unit is an inexpensive and compact approach for the use in the field of low-cost microscopy. However, further improvements in order to increase accuracy and enhance linear movement with little to no backlash must be considered.