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A model for DNA detection by metal-enhanced fluorescence from immobilized silver nanoparticles on solid substrate
Jian Zhang1, Joseph R Lakowicz
1Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, Maryland 21201, USA.
The Journal of Physical Chemistry. B
|February 14, 2006
Summary
This study presents a novel method using silver nanoparticles coated with N-(2-Mercaptopropionyl)glycine (tiopronin) to detect DNA hybridization. The layer-by-layer assembly of these nanoparticles enhances fluorescence and absorbance, enabling sensitive DNA detection.
Area of Science:
- Nanotechnology
- Biochemistry
- Analytical Chemistry
Background:
- Silver nanoparticles (AgNPs) offer unique optical properties for biosensing.
- Functionalization of nanoparticles is crucial for targeted biomolecule detection.
- Oligonucleotide-mediated assembly provides precise control over nanoparticle arrangement.
Purpose of the Study:
- To develop a novel method for detecting DNA hybridization using functionalized silver nanoparticles.
- To investigate the relationship between nanoparticle layer accumulation and signal enhancement.
- To demonstrate the utility of this method for sensitive DNA detection via spectral changes.
Main Methods:
- Preparation of tiopronin-coated silver nanoparticles via a modified Brust method.
- Ligand exchange to introduce thiolate single-stranded oligonucleotides.
- Layer-by-layer immobilization onto a solid substrate through DNA hybridization.
- Detection of DNA hybridization using absorbance and fluorescence spectroscopy.
Main Results:
- Successful immobilization of functionalized silver nanoparticles onto a substrate.
- Enhanced fluorescence intensity and plasmon absorbance with increasing nanoparticle layers.
- A plateau in fluorescence enhancement observed at the 10th particle layer.
- Demonstrated detection of DNA hybridization through spectral shifts.
Conclusions:
- The developed nanoparticle-based method enables sensitive detection of DNA hybridization.
- Increasing nanoparticle layers significantly contributes to signal enhancement.
- This approach offers a promising platform for advanced biosensing applications.
