A highly sensitive detection platform for scrub typhus using multi-fluorescence nucleic acid probes and STORM imaging

Area of Science:

• Biotechnology
• Molecular Biology
• Biosensing

Background:

• Nucleic acid testing (NAT) is crucial for diagnostics but traditional methods face limitations like long processing times and false positives.
• Existing single-molecule detection methods struggle with weak signals and photobleaching.
• There is a need for improved biosensing platforms for sensitive and specific pathogen DNA detection.

Purpose of the Study:

• To develop an amplification-free biosensing platform for sensitive and specific single-molecule detection of Orientia tsutsugamushi DNA.
• To overcome limitations of traditional nucleic acid testing and current single-molecule detection techniques.

Main Methods:

• Utilized multi-fluorophore nucleic acid probes synthesized via click chemistry.
• Incorporated 5-Ethynyl-dUTP (5-EdUTP) into amplicons for fluorophore conjugation.
• Employed Stochastic Optical Reconstruction Microscopy (STORM) for single-molecule localization and quantification.

Main Results:

• Achieved a detection limit of 2.74 aM for Orientia tsutsugamushi DNA.
• Demonstrated excellent specificity and substantial signal amplification through STORM.
• Clinical validation with 11 samples showed 100% sensitivity and specificity.

Conclusions:

• The developed platform provides a simple, rapid, and robust solution for single-molecule detection.
• It is a valuable tool for detecting low-abundance biomarkers.
• Shows significant promise for early disease diagnosis and pathogen identification.