Sulfhydryl-mediated etching suppression of gold nanostars for rapid and sensitive detection of bacterial pathogens

Abstract

Human infectious diseases caused by bacterial pathogens, such as meningitis and pyaemia, threaten the public health worldwide due to their acute onset and high mortality. Sensitive and rapid detection of bacterial pathogens is urgent for the treatment of infectious diseases clinically. However, current techniques are generally time-consuming and require large-scale equipment. Plasmonic nanosensors built on metallic nanomaterials have emerged as excellent tools for biomedical diagnostics. Herein, we report an etching suppression strategy for the sensitive and rapid detection of bacterial pathogens through gold nanostars. Sulfhydryl-containing ligands suppress the iodide-mediated surface etching of gold nanostars, depending on the type, concentration, and size of sulfhydryl-containing ligands. Using mercaptophenylboronic acid (MBA) and Pseudomonas aeruginosa (P. aeruginosa)-specific aptamer as multifunctional ligands, we specifically identify bacterial pathogens through sulfhydryl-mediated etching suppression with a linear detection range from 10 to 106 CFU/mL and a limit of detection of 2 CFU/mL. This etching suppression-based strategy enables the detection of Neisseria meningitidis in the cerebrospinal fluid and P. aeruginosa in the serum within 15 min, showing great potential as a point-of-care platform for clinical diagnosis.