Poly(styrene-4-sulfonate)-protected copper nanoclusters as a fluorometric probe for sequential detection of cytochrome c and trypsin

Mikrochim Acta. 2018 Jul 21;185(8):383. doi: 10.1007/s00604-018-2920-5.

Abstract

Stable copper nanoclusters (CuNCs) were prepared by utilizing D-penicillamine as both the stabilizer and reductant. The emission of the CuNCs (with excitation/emission peaks at 390/645 nm) is largely stabilized by coating with poly(sodium-p-styrenesulfonate) (PSS). Cytochrome c (Cyt c) quenches the fluorescence of the PSS-coated CuNCs, and this effect was exploited to design a quenchometric fluorometric assay for Cyt c. If trypsin is added to the loaded CuNCs, it will hydrolyze Cyt c to form peptide fragments, and fluorescence is gradually restored. A highly sensitive and fluorometric turn-off-on assay was constructed for sequential detection of Cyt c and trypsin. The linear ranges for Cyt c and trypsin are from 8.0 nM to 680 nM, and from 0.1 to 6.0 μg mL-1, and the lower detection limits are 0.83 nM and 20 ng mL-1 for Cyt c and trypsin, respectively. Graphical abstract Schematic illustration of the fluorometric assay for trypsin based on the electron transfer between poly(p-styrenesulfonate)-protected copper nanoclusters (PSS-CuNCs) and cytochrome c (Cyt c).

Keywords: Copper nanoclusters; Electron transfer; Fluorescence; Penicillamine; Stern-Volmer equation; Turn-off-on.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Copper / chemistry*
  • Cytochromes c / analysis*
  • Cytochromes c / chemistry
  • Fluorescent Dyes / chemistry*
  • Fluorometry / methods*
  • Humans
  • Hydrolysis
  • Metal Nanoparticles / chemistry*
  • Models, Molecular
  • Polystyrenes / chemistry*
  • Protein Conformation
  • Time Factors
  • Trypsin / analysis*
  • Trypsin / chemistry

Substances

  • Fluorescent Dyes
  • Polystyrenes
  • polystyrene sulfonic acid
  • Copper
  • Cytochromes c
  • Trypsin