The effect of gold nanoparticle capping agents on 1O2 detection by singlet oxygen sensor green

Singlet Oxygen Sensor Green (SOSG) is the most widely used fluorescent probe for detecting singlet oxygen (O-1(2)). O-1(2) can be efficiently produced by exciting the surface plasmon of gold nanoparticles with laser pulses. However, gold nanoparticles are usually embedded in a chemical stabilizer that can interact with SOSG, leading to erroneous detection of O-1(2). This article shows that the emission properties of SOSG strongly depend on the concentration of cetyltrimethylammonium bromide (CTAB), a capping agent widely used for nanoparticles synthesis and stabilization. The sensitivity of SOSG to O-1(2) is also drastically affected by the presence of CTAB. This effect is due to the fluorescent probe's aggregation in CTAB premicellar aggregates and micelles, and the emergence of fluorescent conformers of the probe in the micelles. Furthermore, the behavior of SOSG in the presence of two other widely-used capping agents, i.e., citrate and Polyethylene Glycol (PEG), is investigated to determine the right nanoparticle stabilizer to use with SOSG probe.

Automated summary

The emission properties of the fluorescent probe SOSG are strongly dependent on the concentration of cetyltrimethylammonium bromide (CTAB), a widely used capping agent for nanoparticles synthesis and stabilization. The presence of CTAB significantly affects SOSG's sensitivity to O-1(2), due to the probe's aggregation in CTAB premicellar aggregates and micelles, as well as the emergence of fluorescent conformers in the micelles. It is important to consider the type of nanoparticle stabilizer when using SOSG probe, with investigations into the behavior of SOSG in the presence of other capping agents like citrate and Polyethylene Glycol (PEG) to determine the most suitable option.