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Label-Free Fluorescence Quantitative Detection Platform on Plasmonic Silica Photonic Crystal Microsphere Array
Shijie Dai1, Wei Li2, Ruimin Xu1
1School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing210023, China.
Analytical Chemistry
|December 15, 2022
Summary
This study introduces a novel label-free fluorescence detection platform using gold nanoparticles and silica photonic crystal microspheres for sensitive Aflatoxin B1 detection. The method offers a rapid, enhanced fluorescence assay with broad application potential.
Area of Science:
- Nanotechnology
- Biosensing
- Analytical Chemistry
Background:
- Label-free detection methods are crucial for simplifying biological and chemical analyses.
- Enhancing intrinsic fluorescence signals is key to improving assay sensitivity.
- Gold nanoparticles (AuNPs) and photonic crystals offer unique optical properties for signal amplification.
Purpose of the Study:
- To develop and demonstrate a proof-of-concept for a label-free fluorescence quantitative detection platform.
- To utilize gold nanoparticle (AuNP) enhanced intrinsic fluorescence of proteins on a silica photonic crystal microsphere (SPCM) array.
- To establish a one-step competitive fluorescence immunoassay for detecting Aflatoxin B1 (AFB1).
Main Methods:
- Immobilization of AFB1-bovine serum albumin and anti-AFB1 monoclonal antibodies on SPCM and AuNPs, respectively.
- Utilizing a one-step competitive fluorescence immunoassay protocol on the SPCM surface.
- Investigating AuNP-enhanced intrinsic fluorescence under near-UV excitation and simulating electric field distribution.
Main Results:
- AuNPs significantly enhanced the intrinsic fluorescence of artificial antigens on the SPCM.
- A maximum near-field enhancement factor of |E/E0| = 20 was achieved due to synergistic photonic crystal and AuNP plasmon effects.
- The method achieved a linear detection range of 0.1–10 ng/mL, a limit of detection of 0.025 ng/mL, and good specificity for AFB1.
- Recovery rates in spiked cereal samples ranged from 84.07% to 101.02%, comparable to ELISA.
Conclusions:
- A novel label-free fluorescence detection platform based on SPCM and AuNPs was successfully developed.
- The synergistic effects of photonic crystals and AuNP plasmonics enable significant fluorescence enhancement.
- This platform shows great potential for sensitive and specific detection in various fields including food safety, medicine, and environmental monitoring.
