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Ratiometric fluorescence probe integrated with smartphone for visually detecting lipopolysaccharide
Xinyu Yang1, Jiayi Li2, Xinhui Tan2
1College of Biological and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, PR China; College of Food and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, PR China.
Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
|October 20, 2022
Summary
A new portable, instrument-free method accurately detects lipopolysaccharide (LPS) using dual-emission fluorescence. This low-cost approach enables visual, quantitative LPS analysis via smartphone, offering broad application potential.
Area of Science:
- Analytical Chemistry
- Nanotechnology
- Biomedical Engineering
Background:
- Lipopolysaccharide (LPS) is a critical indicator of bacterial contamination, necessitating sensitive and accessible detection methods.
- Current LPS detection often requires complex instrumentation, limiting its use in resource-limited settings.
- Developing portable, instrument-free analytical tools is crucial for rapid diagnostics and quality control.
Purpose of the Study:
- To develop a novel, portable, and instrument-free method for the quantitative detection of lipopolysaccharide (LPS).
- To establish a dual-emission ratiometric fluorescence sensing system for enhanced detection accuracy.
- To enable visual, smartphone-based LPS analysis for broader accessibility.
Main Methods:
- A dual-emission ratiometric fluorescence sensing system was designed using red-emitting gold nanoclusters (Au NCs) as a reference and blue-emitting silica quantum dots (Si QDs) as a response probe.
- LPS-specific aptamers were covalently grafted onto the Si QDs surface for targeted recognition.
- Fluorescence intensity ratios (FL ratio, I461 nm/I643 nm) were correlated with LPS concentrations to establish a quantitative analysis framework.
- Smartphone-based color analysis (RGB values) was employed for visual detection.
Main Results:
- The method demonstrated a linear detection range for LPS from 50-3000 ng/mL.
- A low limit of detection (LOD) of 29.3 ng/mL was achieved.
- Practical application in normal saline samples yielded high recovery rates (97.7-103.8%), validating the method's accuracy.
- Visual detection was successfully achieved by converting image colors to RGB values via a smartphone platform.
Conclusions:
- The developed portable, instrument-free method offers a reliable and accessible approach for quantitative LPS detection.
- The dual-emission ratiometric fluorescence system combined with aptamer recognition provides high specificity and sensitivity.
- The smartphone-based visual analysis capability significantly enhances the method's practicality for on-site and low-cost applications.
