Charge control of biomolecules by photocleavage in high vacuum

This thesis summarizes the work performed from March 2020 – April 2024 as part of a collaboration between the Köhler group (University of Basel), Marcel Mayor (University of Basel) and the Arndt group (University of Vienna). The author YH designed experiments in collaboration with the Arndt group and performed synthesis of photocleavable tags and bioconjugation at the University of Basel. The gas-phase cleavage experiments were carried out by the collaborating group of Markus Arndt at the University of Vienna.
Different photocleavable tags, which can be cleaved under different wavelengths, were designed and synthesized. The optimized tags were then attached to a series of biomolecules. Charged particles can be generated by ESI/MALDI, after which positive/negative charges can be removed by photo-induced cleavage with a laser to achieve neutralization.
In chapter 1, a BODIPY-based photocleavable tag was designed and synthesized for the application with 532 nm laser under positive mode.
In chapter 2, redesigned Ru(II) complexes were investigated for the application with 355 nm laser under positive mode.
In chapter 3, a new photocleavage mechanism of Ru(II) complexes under concomitant electron transfer was explored.
In chapter 4, two generations of rotaxanes stoppered with a Ru(II)-photocage were explored for the removal of multiple charges with a single bond cleavage.
In chapter 5, a nitrodibenzofuran-based photocleavable tag was investigated for the application with 355 nm laser under negative mode.
In parallel, new bioconjugation methods were developed for the attachment of photocleavable tags in chapter 6.