NanoVidere - Photochromic Layers for Nanoscopy

• Applicant: Professor Dr. Andreas Schmidt
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation ; Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 504588119

This project aims to develop a new microscopy technique basing on high-resolution far field fluorescence microscopy such as the stimulated emission depletion microscopy (STED) to optically examine surfaces with nanoscale resolution. To improve the resolution the surfaces will be covered by photochromic layers (absorbance modulation layers; AML) which reversibly change their color by photoirradiation by an activating laser to decrease the transmittance. By means of a doughnut mode of the activating laser, an aperture is formed for the measuring laser, which can solely detect signals through the transparent hole in the middle of the doughnut. The AML group of the project (Institutes of Organic Chemistry and Physical Chemistry as well the Max-Planck Institute for Biophysical Chemistry, Department NanoBiophotonik) will prepare layers containing 1,2-bis(thienyl)ethenes as photochromic molecules in a polymeric or an organic matrix. The objective of this subproject is the identification of suitable photochromic molecules and their synthesis for further investigations, as no photochromic molecule reported so far fulfills the specific requirements for application in nanoscopy. The suitability to prepare absorbance modulation layers will i.a. be determined by the fatigue resistencies, irradiation wavelengths, quantum efficiencies for the reversible switching processes, transparencies, and resistance towards crystallization in the matrix. After the syntheses, characterizations, and evaluations in collaboration with our project partners, suitable photochromes will be delivered for application in nanoscopy.

• DFG Programme: Research Grants
• Co-Investigators: Professor Jörg Adams; Dr. Vladimir Belov; Professor Stefan W. Hell