Project Details
Projekt
High-Pressure Freezing System
Subject Area
Basic Research in Biology and Medicine
Term
Funded in 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 559352646
High-Pressure Freezing revolutionized the way to preserve the cellular ultrastructure and therefore to visualize biological samples in electron microscopy with high spatial resolution. Imaging biological specimens with an electron microscope is challenging due to the intrinsic nature of electrons and their interactions with matter. Specimens must be placed in a high vacuum and, in the case of transmission electron microscopy, be thin enough (< 300 nm) to allow successful image acquisition. Therefore, biological specimens cannot be imaged in their native state and require extensive processing. The first step in any biological EM sample preparation is fixation. It aims to preserve the ultrastructure as closely to its native state as possible. Currently the best way to fix cellular structures without introducing possible structural alterations is by cryofixation. It is achieved within milliseconds and ensures simultaneous immobilization of all molecular components, stabilizing cellular structures in a hydrated state. In contrast, chemical fixation methods face two major limitations: a relatively slow fixation rate, unable to match the rapid pace of many cellular events, and the selective nature of chemical crosslinking. As a result, it can introduce artifacts such as cellular rearrangement, deformation, and shrinkage due to slow diffusion, osmolarity imbalances and the selective reactivity of aldehydes. In contrast, high-pressure freezing simultaneously immobilizes and stabilizes all cellular components, capturing snapshots of highly dynamic cellular processes. The exceptional cellular preservation achieved by high-pressure freezing is frequently coupled to other powerful approaches in cell biology, such as correlative light and electron microscopy (CLEM), three-dimensional reconstruction by electron tomography and immunogold-based detection of proteins and other molecules (preservation of antigenicity for immunolabeling). The proposed high-pressure freezing device would provide institutes at the Heinrich Heine University (HHU), access to a state-of-the-art electron microscopy sample preparation technique that was previously unavailable. This advanced preparation technique for optimal ultrastructural preservation will enable researchers to explore the ultrastructure of a wide range of biological samples close to a native state with a level of preservation quality that chemical fixation cannot achieve. Once implemented at the Center for Advanced Imaging (CAi), the imaging core facility of the Faculty of Mathematics and Natural Science at HHU, would ensure that the necessary expertise is available to efficiently apply the high-pressure freezing technique to various scientific needs, in order to increase the quality of related research projects.
DFG Programme
Major Research Instrumentation
Major Instrumentation
Hochdruckgefriergerät
Instrumentation Group
8541 Einfrieranlagen zur Probenvorbereitung, z.B. in der Mikroskopie
Applicant Institution
Heinrich-Heine-Universität Düsseldorf
