Analysis of native biological surfaces using a 100 kV massive gold cluster source

Area of Science:

• Surface Science
• Analytical Chemistry
• Biophysics

Background:

• Analysis of native biological surfaces requires sensitive molecular detection methods.
• Existing techniques like time-of-flight-secondary ion mass spectrometry (TOF-SIMS) and matrix assisted laser desorption ionization-mass spectrometry (MALDI-MS) have limitations in sensitivity and spatial resolution for certain applications.

Purpose of the Study:

• To demonstrate the advantages of a novel 100 kV platform equipped with a massive gold cluster source for analyzing native biological surfaces.
• To evaluate the performance of large gold cluster projectiles in enhancing secondary ion yield for molecular analysis.

Main Methods:

• Utilized a new 100 kV platform with a massive gold cluster source (520 keV Au(400)(4+)).
• Investigated molecular ion emission as a function of projectile size, comparing gold clusters to smaller projectiles (130 keV Au(3)(1+) and 43 keV C(60)).
• Performed comparative analysis using 520 keV Au(400)(4+) TOF-SIMS and MALDI-MS on a rat brain sagittal section.

Main Results:

• Achieved a ~100-fold increase in secondary ion yield with 520 keV Au(400)(4+) projectiles compared to smaller projectiles.
• Observed molecular ion yields of tens of percent for abundant components per projectile impact.
• Demonstrated similar lipid profiles and relative intensities between 520 keV Au(400)(4+) TOF-SIMS and MALDI-MS data on rat brain tissue.

Conclusions:

• The 520 keV Au(400)(4+) projectiles offer a significant improvement in secondary ion yield for molecular analysis.
• This technology provides an attractive probe for submicrometer molecular mapping of native biological surfaces.
• The high yield of analyte-specific ions facilitates detailed surface characterization.