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

Abstract

Singlet Oxygen Sensor Green (SOSG) is the most widely used fluorescent probe for detecting singlet oxygen (1 O 2). 1 O 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 1 O 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 1 O 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 change in the probe configuration. Furthermore, the behavior of SOSG in the presence of two other widely-used surfactants, i.e., citrate and Polyethylene Glycol (PEG), is investigated to determine the right nanoparticle stabilizer to use with SOSG probe.

Coating gold nanorods with silica prevents the generation of reactive oxygen species under laser light irradiation for safe biomedical applications

“…Fluorescence measurements are carried out using the experimental setup previously described, 33 the working principle of which is recalled in Fig. 1.…”

“…22 and 23) as those detailed in a recent study. 33 The PEG-stabilized AuNRs obtained in this way are used as reference materials for measuring ROS production.…”

“…We use PEG rather than CTAB as a nanoparticle stabilizer because CTAB alters the emission properties of SOSG and its response to 1 O 2 , as recently demonstrated. 33 Concerning DHR, 2 mg of the solid product are dissolved in 2 mL of dimethyl sulfoxide (DMSO). The solutions for the experiments are prepared by mixing 1 mL of PEGylated AuNRs in water (respectively AuNRs@SiO 2 in water) with 10 μL of aqueous DHR.…”

“…At last, the IR laser is turned ] is observed before the excitation of the PEGylated AuNRs and AuNRs@SiO 2 . This initial emission is due to the presence of oxidized SOSG molecules, 33 which most probably stems from the synthesis of 1 O 2 by SOSG itself upon the irradiation at 515 nm wavelength. 55 In the case of DHR [Figs.…”

Generation of sub-5 nm AuNPs in the special space of the loop-cluster corona of a polymer vesicle: preparation and its unique catalytic performance in the reduction of 4-nitrophenol

“…We should note here that one of the characteristic features of small gold nanoparticles is in their oxygen adsorption and oxygen activation on their surface, and thus, gold nanoparticles can be used as very useful oxidation catalysts. [39][40][41][42][43][44][45] To understand the reason for the oxygen-induced long induction time in our AuNP@LCCV system, the interactions between gold nanoparticles and oxygen should be considered. It is well known that when 4-NP is mixed with NaBH 4 , the solution becomes yellow due to the formation of 4-nitrophenolate anions, whose reduction causes the yellow color to disappear.…”