mass spectrometric imaging started in 1997, when researchers at the university of texas medical school started to apply maldi mass spectrometry to tissue sections, recording spectra from multiple positions. based on this data, mass spectrometric images were assembled. Obviously, since this method aimed at depicting differences in localization, the sample preparation protocol had to be changed from a simple drop deposition to a more elaborate technique.
a long journey
in an effort to deposit the matrix in an imaging-compatible way, many things were tested. The fundamental problem:
the matrix must be applied in a solution to the surface, so that the analytes are extracted from the tissue and co-crystallize with the matrix. at the same time, we need to preserve the spatial orientation within the tissue…
this posed a significant challenge and scientist spent over 10 year in in the process to find a suitable solution, ideas ranging from piezo-electric drop deposition to heated nebulizers. one particular challenge in this process posed the matrix solution to be sprayed, which is typically of a saturated organic solution. this bears the problem of clogging the system and leading to a un-reproducible or even failed deposition.
based on our gained experience, we identified the following requirements for a deposition system:
- fully automated spray of multiple solution
- reproducible – deposition of a defined surface concentration
- no maintenance – automated procedures for priming, rinsing and cleaning
- compatibility with a wide range of liquids, including concentrated organic solutions
- simple web-based user interface accessible over LAN and WLAN
- flexible protocol (g-code), allowing a full customization of procedures
- embedding in automation workflow – open design to allow compatibility with plate handling robots
- no contamination – focused spray
our team of scientists active in mass spectrometric imaging for over 10 years, experienced mechanical engineers and software designers decided to combine their efforts to provide a solution to the challenge. with the combined experience, the period from the idea to the first fully functional prototype was less than 6 months.