Optimized surface acoustic wave nebulization facilitates bacterial phenotyping

Liang T, Schneider T, Yoon SH, Oyler BL, Leung LM, Fondrie WE, Yen GS, Huang Y, Ernst RE, Nilsson E, Goodlett DR. ‎Int J Mass Spectrom, 2018 Apr 427:65-72. doi.org/10.1016/j.ijms.2017.09.007

We report on the characterization of three different Surface Acoustic Wave Nebulization (SAWN) chip designs for use in mass spectrometric (MS) analysis of the bacterial glycolipid known as lipid A. We used three different statistical methods to objectively calculate MS noise level and, subsequently, signal-to-noise ratio for the purpose of choosing the optimum SAWN chip between three different designs. The best performing standing wave SAWN chip enabled MS detection of 125 fmol of the commercial standard monophosphoryl lipid A. All three chips allowed detection of lipid A extracted from 9 × 104 CFU of Francisella novicida. Finally, we show that SAWN-MS could be used to distinguish between different Gram-negative bacterial species based on their lipid A MS profiles, which has implications in the field of bacterial phenotyping.