Quantitative imaging of amyloid beta peptide (Aβ) in Alzheimer's brain tissue by laser ablation ICP-MS using gold nanoparticles as labels

Imaging vicinal dithiol of arsenic-binding proteins in the mouse brain with amplification by gold nanocluster Au22(GSH)18

A quantitative imaging strategy for the vicinal dithiol (VD) of arsenic-binding proteins in the mouse brain is reported. 2-p-Aminophenyl-1,3,2-dithiarsenolane (PAO-EDT) couples to gold nanoclusters Au₂₂(GSH)₁₈ to form conjugate Au₂₂-PAO-EDT (APE). PAO-EDT in APE selectively binds VD with 1 : 1 stoichiometry. After tagging the mouse brain with APE, VD imaging is realized by laser ablation ICP-MS. VD correlates linearly with ¹⁹⁷Au in APE offering a 22-fold amplification and a LOD of 5.43 nM. It is found that the cerebral cortex and hippocampus are most affected in an arsenic poisoned mouse brain. This study provides useful information for further understanding the mechanisms underlying the biological effects of arsenic on the living body.