Gold nanoclusters-based fluorescence assay for detection of lipopolysaccharide endotoxins

Abstract

Accurate detection of bacterial endotoxin levels is crucial for effective pharmaceutical and food quality control. Endotoxins, specifically lipopolysaccharides, trigger significant inflammatory responses. Gold nanoclusters (AuNCs) emerge as promising fluorescent nanotags due to their facile synthesis, broad Stokes shift, and remarkable photostability. This study pioneers the use of fluorescent AuNCs for endotoxin detection. Glutathione-stabilized gold nanoclusters (GSH-AuNCs) were synthesized and thoroughly characterized. Lipopolysaccharides were extracted from the bacterial cells of Pseudomonas putida and Azospirillum baldaniorum. The correlation between the fluorescence intensity changes of GSH-AuNCs and the concentration of endotoxin was established. Interaction with endotoxin micelles resulted in increased fluorescence intensity and a blue shift in the emission peak, attributed to aggregation-induced emission (AIE). The detection mechanism involves the interaction between nanoclusters and lipopolysaccharide micelles. The sensitivity of the assay is affected by the size of the lipopolysaccharide micelles. Thus, we have developed a novel nanosensor for endotoxin detection without the need for additional recognition molecules. It shows potential for application in detecting endotoxins within pharmaceutical preparations and buffer solutions. This research was supported by the Russian Science Foundation, Grant number № 23-24-00246 (https://rscf.ru/project/23-24-00246/).

Speaker

Daniil S. Chumakov
Institute of Biochemistry and Physiology of Plants and Microorganisms, Saratov Scientific Centre of the Russian Academy of Sciences (IBPPM RAS)
Russia

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