Label-Free Direct Detection of 4MU by Plasmon Enhanced Fluorescence Sensing Based on Ag@SiO₂ NPs

Area of Science:

• Analytical Chemistry
• Nanotechnology
• Biomedical Sensing

Background:

• 4MU is a key component in Compound Dantong Capsules (CDC), used for treating gallbladder-related ailments.
• Existing analytical methods for 4MU detection are limited by poor selectivity, complexity, and high costs.
• There is a critical need for a simple, economical, and selective label-free detection method for 4MU.

Purpose of the Study:

• To develop a novel label-free fluorescence sensing system for direct 4MU detection.
• To utilize plasmon enhanced fluorescence (PEF) with Ag@SiO2 nanoparticles (Ag@SiO2NPs) to improve detection performance.
• To validate the method's efficacy and reliability for analyzing 4MU in pharmaceutical samples.

Main Methods:

• Fabrication of Ag@SiO2 nanoparticles (Ag@SiO2NPs) as a fluorescence enhancer.
• Development of a label-free fluorescence sensing system leveraging the plasmon enhanced fluorescence (PEF) effect.
• Quantification of 4MU concentration and determination of the limit of detection (LOD).

Main Results:

• The 4MU-Ag@SiO2 system demonstrated a significant fluorescence enhancement factor of 31.296 ± 0.864.
• The developed method achieved a wide linear detection range for 4MU from 12.5 nM to 50 µM.
• The limit of detection (LOD) for 4MU was substantially reduced to 0.16 nM, a significant improvement from 1.03 nM.

Conclusions:

• The label-free fluorescence sensing system based on PEF using Ag@SiO2NPs offers a highly sensitive, selective, stable, and cost-effective method for 4MU detection.
• The system successfully quantified 4MU in Compound Dantong Capsules (CDC) samples, showing excellent correlation and reliability.
• This approach holds significant potential for practical applications in pharmaceutical analysis and other fields requiring sensitive fluorescence detection.