Turn-on detection of glutathione S-transferase based on luminescence resonance energy transfer between near-infrared to near-infrared core-shell upconversion nanoparticles and organic dye.

Glutathione S-transferase (GST) is a detoxification enzyme of the liver and kidney. Based on the toxicological effect of GST, it is of great significance to develop a rapid and sensitive detection method for GST. In this work, a new luminescence resonance energy transfer (LRET) system has been designed to detect glutathione S-transferase in the near-infrared (NIR) region by utilizing NaGdF4:Yb3+,Tm3+@NaYF4 upconversion nanoparticles (UCNPs) as the donor and NIR dye-806@Glutathione (IR806@GSH) as the acceptor. NaGdF4:Yb3+,Tm3+@NaYF4 UCNPs were synthesized by a coprecipitation method and surface modification of NOBF4. The donor (positively charged) interacted with the acceptor (negatively charged) via electrostatic interactions to bring them into close proximity; then, LRET occurred and the luminescence was quenched. In the presence of GST, GST can specifically interact with the GSH of IR806@GSH molecule, making IR806@GSH far away from the donor surface, inhibiting the LRET, and restoring the luminescence of the UCNPs. There was a good linear relationship between the luminescence recovery intensity of UCNPs and GST concentration, ranging from 0.11 to 14.19 nM, and the detection of limit was 0.06 nM. The method has been used in the detection of GST in human serum samples and is expected to have potential applications in the biological field. Graphical abstract A luminescence resonance energy transfer system was developed for determination of glutathione S-transferase in the near-infrared region by utilizing NaGdF4:Yb3+,Tm3+@NaYF4 upconversion nanoparticles as the donor and NIR dye-806@Glutathione as the acceptor.