Bioanalytical Research

Bioanalytical Research Group

Experiments done in 1988/89 with the first nano-electrospray device in the physics department of the University Münster/Germany demonstrated that a nano-electrospray generates systematically droplets that are so small that each droplet contains on the average only one analyte molecule dissolved in the original solution [1]. There were two projects born out of this observation: 

1. When directed towards a vacuum system a nano-electrospray could be a highly efficient ion source for molecules of unlimited mass. The analyte molecules would be cooled by solvent evaporation and passively released into the vacuum system. 

2. Similar to the use of molecular beam deposition in vacuo a nano-electrospray could be used to synthesise designed molecular layers using large molecules with interesting properties. 

The first project was realised in 1992 at the European Molecular Biology Laboratory (EMBL, Heidelberg, Germany), when the nano-electrospray device was combined with a mass spectrometer. It could be directly interfaced with the vacuum system, generated very large and stable ions and was more than a hundred times more efficient than any other electrospray ion source at the time. It was the technical base on which low-level protein identification and sequencing was developed. 

The second project was undertaken at the Max Planck Institute for Biophysics (Frankfurt, Germany). The aim was to synthesise large, flat biological membranes with integrated membrane proteins from gas phase. Their purpose was to bring the biochemical properties of membrane proteins to the macroscopic world and to generate an in-vitro system to study membrane protein complex assembly. 

1. M. Wilm, “Synthesis of Extended, Self-Assembled Biological Membranes containing Membrane Proteins from Gas Phase,” bioRxiv, vol. 23, pp. 661215, 2019