Microrobotic Streak Seeding For Protein Crystal Growth

We present a microrobotic system for protein crystal micromanipulation tasks. The focus in this paper is on the task known to crystallographers as streak seeding – it is used to entice certain protein crystals to grow. Our system features a set of custom designed micropositioner end-effectors we call microshovels to replace traditional tools used by crystallographers for this task. We have used micro-electrical mechanical system (MEMS) techniques to design and manufacture various shapes and quantities of microshovels. Visual input from a camera mounted on the microscope is used to detect the locations of the source crystals which the tool needs to touch as well as the locations of the target protein droplets for seeding. We present experimental results that illustrate the applicability of our approach.