Cryo-EM Sample Handling

The Nobel prize in chemistry recently awarded to Dubochet, Frank, and Henderson, for developing cryo-electron microscopy methods for high resolution structure determination in biomolecules is a testament to cryo-electron microscopy’s importance. While cryo-electron microscopy resolution, imaging cameras, and data analysis methods have developed considerably over the years, the preparation and handling of suitable cryogenic thin samples lags. Thus, this proposed work aims in improving cryogenic sample handling. To provide artifact-free cryo-electron microscopy samples, we propose to develop ex situ cryo focused ion beam milled sample handling and micromanipulation methods. Applying these cryogenic sampling technique and methods to manipulate focused ion beam prepared samples will allow a fast, easy, reproducible, and cost-effective method compared to existing techniques. We propose to perform the manipulation ex situ or outside of the expensive focused ion beam instrument. In Phase I, we showed that these new methods are indeed possible and ex situ sample manipulation can be performed in just 3.5 minutes, compared to up to an hour for current in situ methodologies. In Phase II, we are going to improve and optimize these methods for ease of use and even faster manipulation times and apply cryo-EM analyses to lipid producing yeast cells that have applications in biofuels. Understanding the structure/property relationships of plant ultrastructure and biomolecules is essential for development of new energy resources, drugs, medical treatments, and treatment of human diseases. Anything that can be done to improve the time and efficiency to results can greatly enhance the human quality of life. Using the proposed methods, we estimate a savings of $100’s - $1,000’s per sample compared to existing sample preparation methods, while improving the time to results from days to hours.