Functionalized Gold Nanoclusters Identify Highly Reactive Oxygen Species in Living Organisms

Abstract

Surface engineering of nanomaterials allows fine tuning of their interactions with biological systems, and thus can benefit their applications in monitoring intracellular events. Herein, the facile synthesis of ligand-functionalized gold nanoclusters (AuNCs) as intracellular probes targeting highly reactive oxygen species (hROS, such as •OH, ClO − , and ONOO − ) is demonstrated. Selected ligands such as quaternary ammonium and oligopeptides are utilized to modulate the surface chemistry of AuNCs. It is shown that AuNCs decorated with the cell-penetrating oligoarginine peptide facilitate cellular uptake and intracellular imaging of hROS in living cells and the zebrafish, with high stability and selectivity.

Direct Observation of Sophorolipid Micelle Docking in Model Membranes and Cells by Single Particle Studies Reveals Optimal Fusion Conditions

“…Upon docking and membrane fusion, the resulting mixing of lipid species and rapid diffusion away from the docking spot will result in fluorescent signal dilution and loss [ 45 , 46 ] (see Figure S9 for time lapse of particle docking and subsequent signal loss). Analysis was performed in python using a custom routine adapted from [ 33 , 47 ]. Shortly, a binary mask was used to integrate the intensity of fluorescence signal localized with cell membrane and internalized or outside of the cell membrane ( Figure 3 ).…”

Strategies of Luminescent Gold Nanoclusters for Chemo-/Bio-Sensing

“…In general, strong oxidants and specific coordinating agents can react with gold, finally resulting in quenching of AuNC fluorescence. Jiang’s group found that the fluorescence of GSH-modified fluorescent could be significantly quenched by hROS (•OH, ClO − , and ONOO − ) instead of wROS (H 2 O 2 and •O 2− ) at the same concentration, showing their excellent selectivity on hROS over wROS (Figure 4) [58]. They argued that the hROS-mediated fluorescence quenching was ascribable to the oxidation of AuNCs by hROS at both the Au sites and GSH sites.…”

“…Schematic illustration of the one-step synthesis of red-emitting AuNCs with versatile surface chemistry, and the fluorescence quenching strategy for the living cell imaging of hROS (•OH, ClO − , and ONOO − ) using the functionalized AuNCs. Adapted with permission from Reference [58] Copyright (2018) Wiley.…”

Hemoglobin-Conjugated Gold Nanoclusters for Qualitative Analysis of Haptoglobin Phenotypes

“…Fluorescent nanoclusters (NCs) have been extensively utilized for biomedical applications in fields such as bioimaging, detection, and medicine [ 1 , 2 , 3 , 4 , 5 , 6 ]. With many kinds of metal NCs, recent advancements have focused on the development of gold NCs (AuNCs) with various surface ligand modifications for detection applications [ 7 , 8 , 9 , 10 , 11 ]. For example, glucose-conjugated AuNCs were applied as a target-specific fluorescent probe to quantitatively detect glucose metabolism rates by glucose transporters overexpressed by U-87 MG brain cancer cells [ 12 ].…”