Dr. Alexander Ripp

Project

Synthesis and Integration of Light-Responsive Molecules in Polymers
During the beginning of my project, I am synthesizing and characterizing light-responsive nucleosides. I will later integrate these nucleosides into polymers, for example DNA. The resulting material will be able to modify its properties in response to light stimulation of different wavelengths.

Project outcomes

In materials science, DNA-based hydrogels have become popular because they can be precisely programmed to form complex structures, with predictable bond strengths. By incorporating light-sensitive molecules like coumarin or arylazopyrazole into DNA, researchers can create light-responsive networks, which change their properties when exposed to light. I was able to develop a fully automated process to create a variety of modified 5’-triphosphorylated oligonucleotides using solid-phase oligonucleotide synthesis (SPOS). By integrating a specific chemical component (P-amidite c PyPa) into the synthesis routine, many modifications using different chemical agents are now possible. Additionally, I and colleagues were able to develop a simple method to synthesize cap nucleotides using P(III)-amidite chemistry as well as create several photoactive P(III)-amidites suitable for SPOS, enabling the construction of light-responsive DNA hydrogels.

Supervisor and dissertation
Prof. Dr. Henning Jessen

Alex Ripp successfully defended his dissertation in July 2024.

Dissertation: Investigations into cap nucleotide synthesis, automation for 5’-triphosphorylated oligonucleotides and photoresponsive oligonucleotide modifications

Moved on to
Position in industry with the company Curevac.

Publications in livMatS

• Harnessing the Photoperformance of N-Methyl-Quinolinone for Gated Photo-Driven Cyclability and Reversible Photolitigation
  M. Streicher, C.-H. Stamp, M. D. Kluth, A. Ripp, C. Calvino (2024). Harnessing the Photoperformance of N-Methyl-Quinolinone for Gated Photo-Driven Cyclability and Reversible Photoligation. Macromol. Rapid Commun, Vol. 45 (22). doi: 10.1002/marc.202400474
• The P(III)-amidite based synthesis of stable isotope labeled mRNA-cap-structures enables their sensitive quantitation from brain tissue* (early access)
  Ripp, A., Krämer, M., Barth, V., Moser, P., Haas, T. M., Singh, J., Huck, T., Gleue, L., Friedland, K., Helm, M., & Jessen, H. J. (2024). The P(III)-amidite based synthesis of stable isotope labeled mRNA-cap-structures enables their sensitive quantitation from brain tissue.
  Angewandte Chemie International Edition, e202414537. doi: 10.1002/anie.202414537
• The aryne phosphate reaction*
  Haas, T., Wiesler, S., Dürr-Mayer, T., Ripp, A., Fouka, P., Qiu, D., & Jessen, H. (2021). The Aryne Phosphate Reaction. Angewandte Chemie. doi: 10.1002/ange.202113231
• Lost in Condensation: Poly-, Cyclo-, and Ultraphosphates*
  Jessen, H. J., Dürr-Mayer, T., Haas, T. M., Ripp, A., & Cummins, C. C. (2021). Lost in Condensation: Poly-, Cyclo-, and Ultraphosphates. Accounts of Chemical Research. doi: 10.1021/acs.accounts.1c00370
• The Aryne Phosphate Reaction*
  Haas, T., Wiesler, S., Dürr-Mayer, T., Ripp, A., Fouka, P., Qiu, D., & Jessen, H. (2021). The Aryne Phosphate Reaction. ChemRxiv. doi: 10.33774/chemrxiv-2021-3mfj8
• Thiocoumarin Caged Nucleotides: Synthetic Access and Their Photophysical Properties*
  Ma, J., Ripp, A., Wassy, D., Dürr, T.,Qiu, D., Häner, M., Haas, T., Popp, C., Bezold, D., Richert, S., Esser, B., Jessen, H. J. (2020). Thiocoumarin Caged Nucleotides: Synthetic Access and Their Photophysical Properties. Molecules, 25(22), 5325. doi: 10.3390/molecules25225325
• Rapid Synthesis of Nucleoside Triphosphates and Analogues*
  Ripp, A., Singh, J., & Jessen, H. (2020). Rapid Synthesis of Nucleoside Triphosphates and Analogues. Current Protocols in Nucleic Acid Chemistry, 81(1), e108. doi: 10.1002/cpnc.108
• Synthesis of Modified Nucleoside Oligophosphates Simplified: Fast, Pure, and Protecting Group Free*
  Singh, J., Ripp, A., Haas, T. M., Qiu, D., Keller, M., Wender, P. A., Siegel, J. S., Baldridge, K. K., & Jessen, H. J. (2019). Synthesis of modified nucleoside oligophosphates simplified: Fast, pure, and protecting group free. Journal of the American Chemical Society, 141(38), 15013-15017. doi: 10.1021/jacs.9b08273
  
  
  * Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy – EXC-2193/1 – 390951807