Here's good news for researchers using high-resolution fluorescence microscopy: For the first time, biocompatible molecular rulers can be used to calibrate the latest super-resolution microscopy methods. Recent advances in super-resolution microscopy have enabled optical resolution to reach a few nanometers, comparable to the size of a cellular molecule. However, validating this resolution on cellular components such as multiprotein complexes has been a challenge due to the lack of a biomolecular reference system capable of precise dye labeling at nanoscale distances.
PicoRuler: A protein-based molecular ruler that tests the optical resolution of biomolecules in the sub-10 nanometer range with the latest super-resolution microscopy methods under real-world conditions. **Gerti Beliu, DALL-E 3 University of Würzburg.
A team of scientists led by Dr. Gerti Belliu and Prof. Markus Sauer of the Rudolf Virchow Centre - Center for Integrative and Translational Bioimaging, Würzburg, Bavaria, Germany, now offers a turning point. They published a novel biocompatible molecular scale, Picorulers (Protein-Based Imaging Calibration Optical Rulers), in the journal Advanced Materials.
Using gene expansion and click chemistry, the research team successfully constructed these custom-made molecular scales. They can be used as precise biomolecular reference structures in fluorescence microscopy.
Picorulers are based on a three-part protein pCNA (proliferating cell nuclear antigen), which plays a central role in DNA replication and repair. By introducing unnatural amino acids at precisely positioned locations, this protein has been modified to enable fluorescent dyes or other molecules to click specifically onto it with minimal ligation errors.
This enables researchers to test the resolution of the latest super-resolution microscopy methods with unprecedented precision on precisely defined cellular biomolecules.
Markus Sauer enthused"The ability to resolve real biological structures at the sub-10 nanometer level marks a new era in bioimaging technology. Compared to previously used man-made macromolecules, our picoruler is not only biocompatible. They also provide unmatched accuracy of test resolution under real-world conditions. "
The scope of applications for this technology extends far beyond the boundaries of traditional microscopes. "Gerti Belu explains:"Our picorulers are not only tools for more precise measurements, but also open the door to deeper and more detailed studies of the complex processes taking place within cells. "
In the long term, further development of picorulers could transform biological and medical imaging with molecular resolution. For the first time, PicoRuler realizes the potential to validate and improve the resolution of new super-resolution microscopy methods on biological samples. This makes them a valuable tool for future elucidation of the molecular organization and interactions of biomolecules in cells.