Advancement of the molecular microscope to enable high-resolution dynamic imaging and unprecedented spatial metabolomic information of living systems
EMSL Project ID
50614
Abstract
The ability to capture and visualize the complex metabolic behavior of living organisms in situ is a bioanalytical grand challenge that has yet to be fully realized. Ambient ionization mass spectrometry methods offer a unique capability in that they can directly probe the chemical content of systems of interest with little to no sample preparation. Of these methods, laser ablation electrospray ionization mass spectrometry (LAESI-MS) is an increasingly popular method that can provide spatial information of nearly every class of biomolecules directly from living samples. LAESI-MS utilizes a mid-infrared laser tuned to the strongest water absorption band (2940 nm; resonant frequency of the O-H vibration). By directing the laser into water-rich samples, like native plant tissue and microbial biofilms, it enables the ability to spatially ablate material from these samples. The resulting ablation plume contains neutral molecules from said samples, so ionization is facilitated using an intercepting in-axis electrospray, which also acts to direct the ionized molecules into the mass spectrometer orifice. Two significant limitations to the conventionally-configured LAESI source is that it generates limited spatial information (i.e., lateral resolution ~200 ?m), and it does not allow for simultaneous detection of other optical channels. Here, we propose the creation of a LAESI microscope source that will provide high lateral resolution (20-30 ?m) metabolite localization, in conjunction with simultaneous in-line fluorescence imaging that can be used to probe microbe location or gene expression, for example. To increase the molecular information that we attain from these measurements, this LAESI source will be coupled to ion mobility spectrometry (IMS)-MS. Development and optimization of the source will first be performed on a drift tube (DT)-IMS system that is robust and well-established. After which, the LAESI source will be coupled to a structures for lossless ion manipulations (SLIM)-MS system. Recent results indicate that SLIM can obtain an IMS resolution that is five times higher than the state of the art commercial instruments. Consequently, the combination of the LAESI microscope source with IMS-MS will enable the ability to visualize dynamic processes within plant and microbial samples, with unparalleled spatial molecular information.
Project Details
Start Date
2018-11-07
End Date
2021-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Velickovic D., R.K. Chu, G.L. Myers, A. Ahkami, and C.R. Anderton. 2019. "An Approach For Visualizing The Spatial Metabolome Of An Entire Plant Root System Inspired by the Swiss-rolling Technique." Journal of Mass Spectrometry. PNNL-SA-142631. doi:10.1002/jms.4363