Label-free fluorescent sensor for one-step lysozyme detection via positively charged gold nanorods

• Published in: Analytical and bioanalytical chemistry Vol. 413; no. 6; pp. 1541 - 1547
• Main Authors: Zhang, Hong, Liu, Pengfei, Wang, Huifang, Ji, Xiaoming, Zhao, Mingqin, Song, Zhaopeng
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2021; Springer; Springer Nature B.V
• Subjects: Adsorption; Analytical Chemistry; Aptamers; Binding; Biochemistry; Characterization and Evaluation of Materials; Chemical detectors; Chemistry; Chemistry and Materials Science; Deoxyribonucleic acid; Design and construction; DNA; Electrodiagnosis; Energy transfer; Fluorescence; Fluorescent indicators; Food Science; Genetic aspects; Gold; Identification and classification; Laboratory Medicine; Lysozyme; Methods; Monitoring/Environmental Analysis; Nanoclusters; Nanorods; Nucleotide sequence; Physiological aspects; Recovery; Research Paper; Signal reconstruction; Silver; Surface energy; Surface properties; Technology application; China; Positively charged gold nanorods; Fluorescent sensor; Lysozyme binding aptamer; Lysozyme detection; DNA-templated silver nanoclusters
• ISSN: 1618-2642; 1618-2650
• DOI: 10.1007/s00216-020-02814-2

In the article, a simple and label-free strategy was proposed for the sensitive detection of lysozyme based on the fluorescence quenching of positively charged gold nanorods ((+)AuNRs) to DNA-templated silver nanoclusters (DNA/AgNCs). To construct the sensor, a DNA template was designed with a C-rich sequence at the 5′-terminal for the synthesis of AgNCs, while a lysozyme binding aptamer (LBA) at the 3′-terminal for the recognition of lysozyme, and such DNA/AgNCs was used as the fluorescence probe. Meantime, the fluorescence signal of such DNA/AgNCs can be quenched based on the electrostatic adsorption of them with (+)AuNRs, due to the surface energy transfer. In the presence of lysozyme, the specific binding happened between the LBA section of DNA/AgNCs and lysozyme, inducing the reduction of the total charge of DNA/AgNCs and weakening the adsorption of them with (+)AuNRs, which directly resulting in the recovery of the fluorescence signal. Besides, the fluorescence signal recovery of DNA/AgNCs has a linear positive proportional relationship with lysozyme concentration in the range of 10 pM–2.0 nM under the optimal conditions. Moreover, a satisfactory recovery (99.6–107.2%) was obtained while detecting lysozyme in human serum samples. Graphical abstract A simple and label-free strategy was proposed for the sensitive detection of lysozyme based on the fluorescence quenching of positively charged gold nanorods ((+)AuNRs) to DNA-templated silver nanoclusters (DNA/AgNCs).