Immunohistochemistry (IHC) is a well-developed tool for visualizing the protein expression in tissue sections. Common IHC methods involve the use of fluorophore conjugated antibodies or enzyme reporter conjugated antibodies to create coloured pigment that reveals the protein distribution. These reporters exhibit serious spectral overlap when used simultaneously and thus neither of fluorophore nor enzyme based multiplex IHC are suitable for studying the dynamic protein-protein interaction networks. Here, gold and silver nanoparticle conjugated antibodies was used for simultaneous imaging of high mass proteins in rat kidney by laser ionization mass spectrometry (LI-MS). Possessing characteristic localized surface plasmon resonance property, both gold and silver nanoparticles efficiently absorb laser energy and induce explosive self-ionization. Abundant mass reporter ions (e.g. Au<sup>+</sup> and Ag<sup>+</sup>) could be generated and detected by MS. Incorporated with the outstanding spectral resolution of mass spectrometry and high specificity of antibody-antigen interactions, this method enables a sensitive detection of high mass proteins which could be a complement to the inability of Matrix-assisted Laser Desorption/ Ionization (MALDI) in large protein imaging.

Immuno-capture laser ionization mass spectrometry: Gold and silver nanoparticles as mass tags for high mass protein imaging

256th National Meeting (2018)

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