Microlensed fiber allows subcellular imaging by laser-based mass spectrometry

Area of Science:

• Analytical Chemistry
• Biotechnology
• Microscopy

Background:

• Mass spectrometry imaging (MSI) provides label-free, high-throughput chemical mapping.
• Rapid analysis in MSI allows for monitoring of dynamic chemical changes.
• Current MSI techniques face limitations in achieving subcellular spatial resolution.

Purpose of the Study:

• To develop a protocol for mass spectrometry imaging (MSI) with subcellular spatial resolution.
• To introduce a universal and economic microlensed fiber technique for laser-based MSI.
• To demonstrate the adaptability of the microlensed fiber across various mass spectrometry methods.

Main Methods:

• Fabrication of a microlensed fiber by grinding an optical fiber.
• Utilizing the microlensed fiber to focus laser radiation for sample ablation.
• Mass spectrometric analysis of the ablated plume.
• Integration with matrix-assisted laser desorption ionization, laser desorption ionization, laser ablation electrospray desorption ionization, and laser ablation inductively coupled plasma.

Main Results:

• Achieved subcellular spatial resolution in MSI.
• Demonstrated the universal applicability of the microlensed fiber with multiple laser-based MSI platforms.
• The experimental setup can be completed in approximately 2 hours by a trained graduate student.
• The technique is adaptable to most laser-based mass spectrometry methods, including atmospheric pressure applications.

Conclusions:

• The microlensed fiber is a cost-effective and universal tool for enhancing spatial resolution in MSI.
• This method enables submicroscale imaging of single cells and biological tissues.
• Existing laser-based MSI platforms can achieve significant breakthroughs in spatial resolution by incorporating the microlensed fiber module.