Sensitive Sulfide Monitoring in Live Cells by Dark-Field Microscopy Based on the Formation of Ag₂S on Au@AgI Core–Shell Nanoparticles

Abstract

Hydrogen sulfide (H 2 S) is the third endogenous gas in mammals that plays an important role in understanding human physiological and pathological processes. However, it remains difficult to measure H 2 S in living biological specimens due to interference of other biothiols (GSH, Cys, Hcy, and thiol-containing proteins) as well as low concentrations of H 2 S (as low as sub-nM). Here, we present Au@AgI core−shell plasmonic nanoparticles (PNPs) as highly sensitive probes to acquire sulfide rapid monitoring in biological environments. When the Au@AgI PNPs are exposed to sulfide, the AgI transforms into Ag 2 S, leading a change of local surface plasmon resonance (LSPR), thereby resulting in a color and light intensity change at the single nanoparticle level which can be monitored by dark-field microscopy (DFM). This strategy has an ultralow limit of detection (LOD) of 33 pM and great antiinterference ability for sulfide detection in biological environments. This method was successfully used for highly sensitive sulfide mapping in live cells and to record the changes of H 2 S levels in different brain regions of rats during acute cerebral ischemia, validating that this method suitable for trace sulfide sensing in biological environments. We anticipate that this sulfide sensor has potential applications for studying complex neurochemical changes.

Low‐Temperature Growth of High‐Quality Ag2HgS2 Crystals for Setup of Weak‐Light UV–Visible–NIR Photodetectors

“…Both Ag 2 S and HgS are easily produced in aqueous system, thermodynamically, since Ag 2 S has a K sp of 6.3 × 10 −50 with a ΔG°f of −40.26 kJ mol −1 and HgS has a K sp of 4.0 × 10 −53 with a ΔG°f of −50.60 kJ mol −1 . [23,24] To simplify the growth procedures, we keep the reaction temperature constant at 200 °C in all investigations. In the actual procedures, we should primarily adjust the amount of raw materials especially increasing the feedstock of (NH 4 ) 2 S to limit possible precipitation of the binary endmembers over a balanced coordination effect between the sources while the growth of the ternary Ag 2 HgS 2 SCRs is not hindered comparably under the same conditions.…”

Recent Advances in Plasmonic Nanostructures Applied for Label‐free Single‐cell Analysis

“…On the basis of abovementioned superiorities, it is proved that the plasmonic nanostructure combining optical equipment is a powerful diagnostic technique to clarify the cell-to-cell differences. in live cells by Au@AgI, real-time and in situ monitoring the etching process of single Au@AgI PNPs by a DFM scattered light technique, time-dependent DFM images of single Au@AgI after exposure to S 2À , large fields of DFM images of single Au@AgI before and after reacting with S 2À , color percentages of the corresponding single Au@AgI and representative DFM images of single Au@AgI before and after adding Na 2 S to the cell culture medium [65]. Copyright (2019) American Chemical Society.…”

“…Meanwhile, the reducing molecules (such as glutathione, GSH) in cells would etch outer MnO 2 nanosheets, resulting in a subsequent blue‐shift of the LSPR spectra, promising to estimate the local redox states at single‐cell level. In another example, Au@AgI core‐shell plasmonic nanoparticles were used to rapid monitor sulfide in living biological specimens with highly sensitivity (Figure 8b) [65]. When exposed to sulfide, AgI was transformed into Ag 2 S, leading a change of LSPR and thereby resulting in a color and light intensity change at the single nanoparticle level.…”

Dark-Field Microscopy: Recent Advances in Accurate Analysis and Emerging Applications

“…Zhang and Fan used the sulfide ion-induced red shift of wavelength and the reduced scattering intensity of Au@Ag nanocube probes for quantitative analysis of trace sulfide ions . Similarly, Lin et al used Au@AgI core–shell probes for sensitive detection of sulfide ions in live cells (Figure A) . Oxidizing substances can induce the oxidation of plasmonic probes, especially highly active silver shells.…”

“…38 Similarly, Lin et al used Au@AgI core−shell probes for sensitive detection of sulfide ions in live cells (Figure 4A). 39 Oxidizing substances can induce the oxidation of plasmonic probes, especially highly active silver shells. Xiao et al sensitively detected permanganate under DFM in a labelfree manner.…”