Protein analysis by desorption electrospray ionization mass spectrometry

Western Michigan University, Kalamazoo MI

Investigators

Abstract

With this award, the Chemical Measurement and Imaging Program in the Division of Chemistry is funding Professor Andre Venter at Western Michigan University to investigate various methods to improve the analysis of protein molecules by desorption electrospray ionization mass spectrometry (DESI-MS). Imaging of tissue samples by DESI is an important new tool to aid in biological tissue imaging. DESI-imaging applications are currently limited to the analysis of small molecules such as lipids, fatty acids, and small molecules. Developing the ability to analyze proteins would extend the capabilities of imaging DESI-MS to determine the spatial distribution of proteins in biological relevant tissues. In addition, Professor Venter will make significant efforts to increase participation of undergraduate students, especially from underrepresented groups in research, and educate the general public about the importance of chemistry in their everyday life through collaboration with the Gwen Frostic School of Art at WMU. Currently when proteins are analyzed by DESI-MS, sensitivity decreases with increasing molecular weight, and poor protein dissolution has been implicated as the major cause. Methods to improve dissolution and desorption such as the application of heat, the addition of a variety of additives to the DESI spray and a delayed desorption DESI sprayer will be investigated separately and in combination. To decipher mechanistic aspects of these mitigation strategies, Professor Venter will separately investigate the effects on dissolution of each, during desorption and ionization by using their previously developed Spray Desorption Collection, and Reflective Electrospray Ionization methods. Construction and characterization of a dual-sprayer DESI configuration will be carried out to determine optimum delay between localized surface wetting and desorption to maximize signal to noise ratios of proteins during DESI analysis, while conserving lateral resolution.