Magnetism-Resolved Separation and Fluorescence Quantification for Near-Simultaneous Detection of Multiple Pathogens

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Molecular Diagnostics

Background:

• Rapid, sensitive, and specific detection of multiple pathogens is crucial for modern medicine but currently limited in clinical practice.
• Existing methods for pathogen separation and collection are often inefficient, hindering timely diagnosis and treatment.
• There is a need for advanced technologies to enable simultaneous pathogen detection and antimicrobial susceptibility testing (AST).

Purpose of the Study:

• To develop a novel strategy for near-simultaneous detection of multiple pathogens using magnetism-resolved separation and fluorescence quantification.
• To create aptamer-modified fluorescent-magnetic multifunctional nanoprobes (apt-FMNPs) for pathogen detection and subsequent AST.
• To evaluate the efficacy of the apt-FMNPs strategy in detecting specific pathogens and assessing their susceptibility to antibiotics.

Main Methods:

• Self-assembly of fluorescent-magnetic multifunctional nanoprobes (FMNPs) using metal coordination interaction with specific components.
• Conjugation of pathogen-specific aptamers to FMNPs to create apt-FMNPs for targeting Escherichia coli O157:H7 (E. coli) and Salmonella typhimurium (S. typ).
• Utilizing discrepant magnetic responses of pathogen@nanoprobe complexes for magnetic adsorption, separation, and fluorescence quantification within one hour.

Main Results:

• The developed apt-FMNPs demonstrated excellent fluorescence quality and distinct magnetic responses for pathogen separation.
• Near-simultaneous detection of multiple pathogens was achieved within 1 hour, exhibiting good linear ranges and low detection limits.
• The apt-FMNPs strategy successfully detected spiked pathogens in real samples and yielded comparable AST results to pure pathogens.

Conclusions:

• The aptamer-modified fluorescent-magnetic nanoprobes (apt-FMNPs) offer a promising platform for rapid, simultaneous detection of multiple pathogens.
• This strategy facilitates direct antimicrobial susceptibility testing (AST), potentially improving the diagnosis and treatment of infectious diseases.
• The developed method addresses the current limitations in clinical pathogen detection, paving the way for advanced molecular diagnostics.