A label-free fluorescent biosensor for the detection of protein kinase activity based on gold nanoclusters/graphene oxide hybrid materials.

Author(s) Liu, Q.; Li, N.; Wang, M.; Wang, L.; Su, X.
Journal Anal Chim Acta
Date Published 2018 Jul 12

Protein kinase (PKA) can regulate many cellular biological processes by phosphorylation substrate peptide or protein. A new fluorescent biosensing method for the detection of PKA activity was developed by using 11-mercaptoundecanoic acid-capped gold nanoclusters (MUA-Au NCs) and graphene oxide (GO) with low background noise. In this strategy, the special designed peptide could be anchored on the surface of MUA-Au NCs by the Au-S bond and also adsorbed on the surface of GO owing to the electrostatic interaction. As a result, the fluorescence of MUA-Au NCs was quenched leading to low background fluorescence due to the forster resonance energy transfer (FRET) between MUA-Au NCs and GO via peptide as a bridge. However, when the substrate peptide was phosphorylated by PKA, the FRET between GO and MUA-Au NCs was disrupted because of the weakened interaction between the phosphorylated peptide and the GO, resulting in recovery of the fluorescence intensity. The developed label-free fluorescence "turn-off-on" method can detect protein kinase activity in the range of 0.6-2.0 U mLwith a detection limit of 0.17 U mL(3σ). The feasibility of this present method for kinase inhibitor screening was also studied by assessment of H-89 kinase inhibition with an ICvalue of 0.049 μmol L.

DOI 10.1016/j.aca.2018.01.053
ISSN 1873-4324
Citation Anal Chim Acta. 2018;1013:7178.

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