CdS quantum dots-based immunoassay combined with particle imprinted polymer technology and laser ablation ICP-MS as a versatile tool for protein detection

Sci Rep. 2019 Aug 14;9(1):11840. doi: 10.1038/s41598-019-48290-2.

Abstract

For the first time, the combination of molecularly imprinted polymer (MIP) technology with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is presented with focus on an optimization of the LA-ICP-MS parameters such as laser beam diameter, laser beam fluence, and scan speed using CdS quantum dots (QDs) as a template and dopamine as a functional monomer. A non-covalent imprinting approach was employed in this study due to the simplicity of preparation. Simple oxidative polymerization of the dopamine that creates the self-assembly monolayer seems to be an ideal choice. The QDs prepared by UV light irradiation synthesis were stabilized by using mercaptosuccinic acid. Formation of a complex of QD-antibody and QD-antibody-antigen was verified by using capillary electrophoresis with laser-induced fluorescence detection. QDs and antibody were connected together via an affinity peptide linker. LA-ICP-MS was employed as a proof-of-concept for detection method of two types of immunoassay: 1) antigen extracted from the sample by MIP and subsequently overlaid/immunoreacted by QD-labelled antibodies, 2) complex of antigen, antibody, and QD formed in the sample and subsequently extracted by MIP. The first approach provided higher sensitivity (MIP/NIP), however, the second demonstrated higher selectivity. A mixture of proteins with size in range 10-250 kDa was used as a model sample to demonstrate the capability of both approaches for detection of IgG in a complex sample.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cadmium Compounds / chemistry*
  • Electrophoresis, Capillary
  • Fluorescence
  • Immunoassay / methods*
  • Immunoglobulin G / analysis
  • Laser Therapy*
  • Mass Spectrometry*
  • Mice
  • Molecular Imprinting*
  • Polymers / chemistry*
  • Proteins / analysis*
  • Quantum Dots / chemistry*
  • Signal Processing, Computer-Assisted
  • Sulfides / chemistry*

Substances

  • Cadmium Compounds
  • Immunoglobulin G
  • Polymers
  • Proteins
  • Sulfides
  • cadmium sulfide