Laser-Induced Acoustic Desorption Mass Spectrometry of Single Bioparticles

摘要

The pioneering work on electrospray ionization (ESI) by Fenn and co-workers as well as matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) by Tanaka et al. and Karas and Hillenkamp now allows the soft ionization and mass measurement of large biomolecules. With the simplicity of the mass spectra, MALDI-MS has become a major tool for current proteomic research and in the diagnosis of diseases. We previously demonstrated that MALDI is also a useful technique for laser desorption/ionization of intact bacterial particles such as Escherichia coli. However, to produce gas-phase ions of viruses and cells that do not have rigid walls, the method is not so applicable because these bioparticles can disintegrate easily when mixed with the matrix and the disintegration proceeds further during the course of matrix crystallization and subsequent laser desorption/ionization processes. Herein, we report a laser-induced acoustic desorption (LIAD) method that allows facile desorption of intact bioparticles (including viruses, bacteria, and mammalian whole cells) for the determination of absolute mass with a quadrupole ion trap (QIT). While LIAD has been demonstrated previously for desorption of intact organic and biomolecular ions, the mass range was limited to less than 20 kDa.