Capillary array electrophoresis imaging of biochemicals in tissue sections

Area of Science:

• Biomedical imaging
• Analytical chemistry
• Neuroscience

Background:

• Mass spectrometry imaging (MSI) is significant for revealing molecular distribution in biological tissues but faces challenges like high cost, technical barriers, and limitations in analyzing certain substances.
• There is a need for complementary, cost-effective imaging techniques to overcome MSI limitations and expand molecular distribution analysis in biological samples.

Purpose of the Study:

• To introduce and validate a novel, cost-effective method, capillary array electrophoresis (CAE) imaging, as an alternative to MSI for molecular distribution analysis.
• To demonstrate the capability of CAE imaging to visualize the spatial distribution of specific molecules within biological tissue sections.

Main Methods:

• A gridding cutter was developed to dissect tissue sections into an array of micro wells for in situ extraction and fluorophore-labeling of analytes.
• Samples within the micro wells were directly analyzed using capillary array electrophoresis with laser-induced fluorescence (CAE-LIF).
• Molecular distribution images were generated by analyzing the separated peaks from CAE-LIF.

Main Results:

• CAE imaging successfully depicted the molecular distribution of amino acid neurotransmitters (glutamine, GABA, alanine, glutamate, aspartate) in rat brain tissue sections.
• The technique revealed global differences in molecular distributions within the tissue.
• A spatial resolution of 1000 μm was achieved, with potential for higher resolution (10-50 μm) determined by capillary bore size.

Conclusions:

• CAE imaging presents a promising, low-cost, and technically accessible method for molecular distribution analysis in biological tissues.
• The technique's versatility allows for the separation of various charged and non-charged, chiral and non-chiral substances.
• CAE imaging serves as a valuable complementary approach to MSI, broadening the scope of molecular imaging in biological research.