Quantitative Imaging of Specific Proteins in the Human Retina by Laser Ablation ICPMS using Bioconjugated Metal Nanoclusters as Labels

Anal Chem. 2018 Oct 16;90(20):12145-12151. doi: 10.1021/acs.analchem.8b03124. Epub 2018 Sep 24.

Abstract

A sensitive methodology using antibody-conjugated gold nanoclusters (AuNCs) was developed for the quantitative bioimaging of specific proteins in biological tissues by laser ablation (LA) coupled to inductively coupled plasma-mass spectrometry (ICPMS). Determination of metallothioneins (MT1/2 protein isoforms) images in human retina tissue sections was carried out as a proof of concept. AuNCs used as label were conjugated to the selected antibody through carbodiimide coupling. A stoichiometry of AuNCs/available antibody of 1:1 was obtained. The high amplification provided by AuNC labels allowed for obtaining the distribution of MT1/2 in the neurosensory retina layers (5 μm thick sections) by LA-ICPMS. Elemental images of 197Au+ were quantified with gelatin matrix-matched standards and then converted to 2D quantitative images of MT1/2 concentration. For validation purposes, average concentrations of MT1/2 obtained in the human retinal layers by LA-ICPMS were successfully compared with those obtained with a commercial ELISA kit.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Enzyme-Linked Immunosorbent Assay
  • Gold / chemistry*
  • Humans
  • Laser Therapy* / instrumentation
  • Mass Spectrometry / instrumentation
  • Metal Nanoparticles / chemistry*
  • Metallothionein / analysis*
  • Retina / chemistry*

Substances

  • Gold
  • Metallothionein