Cryo-Electron Microscope (Cryo-EM) has become the technique of choice for structural biology. However, a major bottleneck in the current single particle cryo-EM is to prepare good quality frozen cryo-EM grids, which often is a trial and-error process. Among many issues, preferred particle orientation and sample damaging by air-water interface (AWI) are common problem in practice.

Current methods for improving particle behavior in vitreous ice required special devices or complicated techniques.

Global Cryo-Electron Microscope market is expected to grow from USD 446.4 million in 2021 to USD 833.8 million in 2028, with a CAGR of 9.3%. The demand for Cryo-EM is expected to expand as it allows the study of biological models while keeping their native and hydrated structural features integral. 

For apoferritin treated with MSBP, the particles were distributed uniformly throughout the vitreous ice layer with few particles at the AWI (Figure 1). For apoferritin without MSBP, an abundance of particles were trapped in the AWI (Figure 2).

Application of MSBP can alleviate the preferred orientation problem of HA trimmer by protecting particles from AWI such that particles can rotate and distribute more freely (Figure 3). Treatment with MSBP could enhance the final map quality of cryo-EM (Figure 4).

Benefits

• A simple method additional to the sample preparation process that could increase the resolution of cryo-EM result without any hardware modification. 
• Metallo-supramolecular branched polymer (MSBP) synthesized in this invention could keep majority of particles away from air-water interface and mitigates preferred orientation.

Reagent kit for cryo-EM sample preparation

IP Status

• Patent application submitted