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Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis
Published on: March 7, 2018
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Functionalized gold nanoparticle-enhanced competitive assay for sensitive small-molecule metabolite detection using
Yong Cao1, Bethany Griffith, Prasanna Bhomkar
1Department of Chemistry, 11227 Saskatchewan Drive. and University of Alberta, Edmonton, Alberta T6G 2G2, Canada. mark.mcdermott@ualberta.ca.
The Analyst
|November 30, 2017
Summary
This study presents a novel sensor for detecting folic acid (FA) using gold nanoparticles and surface plasmon resonance (SPR). The method achieves sensitive nanomolar detection, enabling potential disease diagnostics.
Area of Science:
- Biosensing and Nanotechnology
- Analytical Chemistry
- Biomolecular Interaction Analysis
Background:
- Small molecule metabolite detection is crucial for disease diagnostics.
- Surface Plasmon Resonance (SPR) is a powerful sensing platform, but direct small molecule detection is challenging.
- Developing portable and simple sensors for metabolites is an active research area.
Purpose of the Study:
- To develop a sensitive and specific SPR-based sensing system for folic acid (FA) detection.
- To overcome the limitations of direct small molecule detection using SPR.
- To establish a competitive assay format for quantifying small molecules.
Main Methods:
- Utilized a competitive assay format combining a periplasmic binding protein (folate binding protein, FBP) with gold nanoparticles (AuNPs) functionalized with FA.
- Immobilized FBP on an SPR imaging substrate to capture FA-conjugated AuNPs.
- Measured the adsorption of FA-conjugated AuNPs in the presence of free FA in solution.
Main Results:
- Successfully developed an SPR-based competitive assay for folic acid detection.
- Optimized FBP immobilization and FA-AuNP binding for enhanced sensitivity.
- Achieved a limit of detection of 2.9 nM for FA by reducing the concentration of FA-conjugated AuNPs, extending the dynamic range to nanomolar levels.
Conclusions:
- The developed competitive assay effectively quantifies free FA in solution by measuring the displacement of FA-conjugated AuNPs.
- This approach demonstrates the potential for sensitive, low-limit detection of small molecules using SPR.
- The methodology is adaptable for detecting various small molecules and holds promise for future multiplexed metabolite analysis.
