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Published on: February 28, 2015
Digitizing Gold Nanoparticle-Based Colorimetric Assay by Imaging and Counting Single Nanoparticles.
Liang Yuan1, Xian Wang1, Yimin Fang1
1State Key Laboratory of Analytical Chemistry for Life Science and Collaborative Innovation Center of Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing, Jiangsu 210093, China.
This study introduces a digital colorimetric assay using surface plasmon resonance microscopy (SPRM) to count individual gold nanoparticles (AuNPs). This method enhances detection sensitivity for various analytes by analyzing nanoparticle aggregation.
Area of Science:
- Nanotechnology
- Analytical Chemistry
- Spectroscopy
Background:
- Colorimetric assays using gold nanoparticles (AuNPs) rely on bulk optical properties.
- Traditional methods suffer from limited sensitivity due to averaging effects, especially at low analyte concentrations.
- Individual nanoparticle behavior is obscured in bulk measurements.
Purpose of the Study:
- To develop a digital colorimetric assay for enhanced analyte detection sensitivity.
- To utilize surface plasmon resonance microscopy (SPRM) for imaging and counting individual AuNPs.
- To overcome the limitations of traditional bulk-based colorimetric assays.
Main Methods:
- Developed a digital assay by imaging and counting individual AuNPs using SPRM.
- Quantified analyte concentration by measuring the percentage of large AuNP aggregates.
- Demonstrated the method using two model systems involving analyte-induced aggregation and disaggregation.
Main Results:
- SPRM enabled the identification of rare AuNP aggregates, significantly improving detection sensitivity.
- The digital assay successfully quantified analyte concentrations based on individual nanoparticle behavior.
- SPRM proved effective for both plasmonic (AuNPs) and non-plasmonic nanomaterials.
Conclusions:
- The proposed digital SPRM-based assay offers a significant improvement in sensitivity over traditional colorimetric methods.
- This technique has the potential to expand colorimetric assays to a wider range of non-plasmonic nanoparticles.
- Digitized nanoparticle counting provides a powerful alternative for sensitive and versatile analyte detection.
