Microrobotic Protein Crystal Mounting Under Visual Guidance

We present a micro-robotic system for protein crystal micro-manipulation. The specific task we focus on is the automated crystal mounting for X-ray data collection. The system features a set of newly designed micropositioner endeffectors we call micro-shovels which address some limitations of the traditional cryogenic loops. We have used micro-electrical mechanical system (MEMS) techniques to design and manufacture various shapes and quantities of micro-shovels. Visual feedback from a camera mounted on the microscope is used to control the micropositioner as it lowers a microshovel into the liquid containing the crystals and approaches a selected crystal for pickup. We present experimental results that illustrate the applicability of our approach.