Laser desorption postionization for imaging MS of biological material

Area of Science:

• Analytical Chemistry
• Mass Spectrometry
• Biophysics

Background:

• Matrix-assisted laser desorption/ionization (MALDI) has limitations for imaging mass spectrometry (MS), particularly for samples with high salt content like bacterial biofilms.
• Vacuum ultraviolet single photon ionization (VUV SPI) is a soft ionization technique offering potential solutions to MALDI's limitations.

Purpose of the Study:

• To review advancements in laser desorption postionization mass spectrometry (LDPI-MS) over the past decade.
• To highlight the application of LDPI-MS for imaging bacterial biofilms and other challenging biological samples.
• To discuss the fundamental principles and future prospects of VUV SPI in imaging MS.

Main Methods:

• Review of literature on VUV SPI and LDPI-MS.
• Description of VUV radiation sources and a newly constructed LDPI-MS instrument with imaging capabilities.
• Demonstration of small molecule detection and imaging in intact biofilms using VUV photons and aromatic tags.

Main Results:

• LDPI-MS effectively overcomes the challenges of imaging analytes in high salt environments, such as bacterial biofilms.
• Successful detection and imaging of small molecules within intact biofilms were achieved using VUV photons.
• Aromatic tags were utilized for targeted detection of specific species within biofilms.

Conclusions:

• LDPI-MS, leveraging VUV SPI, shows significant potential for advancing imaging MS of complex biological samples.
• The technique offers improved sensitivity and applicability for samples resistant to traditional methods like MALDI-MS.
• Future developments in LDPI-MS are expected to expand its utility for imaging intact biological systems.