Enhanced Fluorescence of Gold Nanoclusters Composed of HAuCl₄ and Histidine by Glutathione: Glutathione Detection and Selective Cancer Cell Imaging

Abstract

Glutathione (GSH) can significantly and selectively enhance the fluorescence intensity of Au nanoclusters (NCs) prepared by blending HAuCl4 and histidine in solution. The quantum yield of the Au NCs after adding GSH can reach above 10%. Besides, GSH capping shifts the excitation peak of Au NCs from ultraviolet (386 nm) to visible light (414 nm) and improves the stability of the Au NCs. The cytotoxicities of the Au NCs with and without GSH for normal lung cells (ATII) and cancerous lung cells (A549) are evaluated. The GSH-capped Au NCs have much less cytotoxicity to both normal and cancer cells, as compared to those without GSH. For Au NCs without GSH, less cytotoxicity is observed in cancer cells than in normal cells. In addtion, the Au NCs can selectively detect GSH over cysteine and homocysteine, the two biothiols which commonly exist in cells that can seriously affect GSH detection. Most importantly, Au NCs without GSH can selectively image the cancer cells, especially for the liver cancer cells whose GSH content is much higher than other cell types. This property makes the Au NCs a powerful probe to distinguish cancer cells from normal cells.

Gold Nanomaterials at Work in Biomedicine

“…It was found that GSH could significantly and selectively enhance the photoluminescence intensity of histidine-stabilized Au clusters. 423 In the presence of GSH, the quantum yield of Au clusters could reach levels above 10% without other thiolate molecules impacting the photoluminescence. Based on this "turn on" strategy, a LOD of 0.2 μM was demonstrated for GSH in the detection range of 150−1200 μM.…”

A Smart Photosensitizer–Manganese Dioxide Nanosystem for Enhanced Photodynamic Therapy by Reducing Glutathione Levels in Cancer Cells

“…16-22 Glutathione (GSH) is an important antioxidant and the most abundant low-molecular weight thiol in vivo, with a concentration range from 1 to 15 mM. 23 At the same time, however, it has been shown to consume 1 O 2 generated by PDT agents, thus greatly reducing the efficiency of PDT and limiting the clinical applications of current PDT agents. 24-26 Therefore, the development of a multifunctional nanosystem which can both enhance the cellular uptake of photosensitizers and decrease the level of GSH in cancer cells in situ is highly desired.…”

In situ growth of fluorescent silicon nanocrystals in a monolithic microcapsule as a photostable, versatile platform

“…52 It is necessary to monitor level of glutathione due to its biological significance in diseaces such as cancer, 53 HIV 54 and heart problems. 55 SiPM were able to in situ reduce KMnO 4 to MnO 2 sheets by immersing SiPM in KMnO 4 aqueous solutions (here we used HD-SiPM).…”