Related Experiment Video
Updated: Jul 22, 2026
09:02
Fabricating a UV-Vis and Raman Spectroscopy Immunoassay Platform
Published on: November 10, 2016
10.3K
pH-tuned reversible self-assembly of Janus particles for enhanced Raman imaging and sensing
Maria Iftesum1, Mohan Kumar Dey1, Alisha Prasad2
1Department of Mechanical and Industrial Engineering, Louisiana State University, Baton Rouge, LA, 70803, USA.
Analytical and Bioanalytical Chemistry
|May 3, 2025
Summary
Controlled self-assembly of Janus particles using pH modulation enhances surface-enhanced Raman scattering (SERS) signals. This pH-driven aggregation optimizes particle spacing and plasmonic coupling for superior SERS-active substrates.
Area of Science:
- Materials Science
- Nanotechnology
- Analytical Chemistry
Background:
- Surface-enhanced Raman scattering (SERS) relies on plasmonic coupling and electromagnetic field distribution for signal amplification.
- Janus particles, with their asymmetric properties, offer potential for controlled self-assembly and tailored nanostructures.
- pH modulation is a viable method to control electrostatic interactions and particle aggregation.
Purpose of the Study:
- To investigate the pH-mediated self-assembly of Janus particles.
- To evaluate the impact of pH-controlled assembly on SERS performance and Raman signal amplification.
- To engineer tunable hotspots for enhanced optical sensing applications.
Main Methods:
- Utilized pH modulation to control electrostatic interactions and induce self-assembly of Janus particles.
- Employed scanning electron microscopy (SEM) to characterize the morphology of the assembled nanostructures.
- Assessed SERS enhancement capabilities using Raman imaging and measurements across various pH conditions.
Main Results:
- Demonstrated that pH-mediated self-assembly effectively controls interparticle spacing and plasmonic interactions.
- Observed significantly amplified Raman signals due to optimized nanostructure formation.
- Identified specific pH ranges that yield optimal SERS enhancement.
Conclusions:
- pH-controlled self-assembly of Janus particles is a critical factor in optimizing SERS substrates.
- This method provides a versatile and reproducible approach for engineering highly sensitive SERS-active materials.
- The developed strategy advances applications in bioanalytical sensing, molecular diagnostics, and environmental monitoring.
Related Concept Videos
01:20Raman Spectroscopy: Overview
The underlying principle of Raman spectroscopy is based on the interaction between light and matter, specifically molecules' inelastic scattering of photons. When a monochromatic beam of light, typically from a laser source, interacts with a sample, most scattered light has the same frequency as the incident light. This is known as Rayleigh scattering.
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and the...
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and the...
01:26Raman Spectroscopy Instrumentation: Overview
A conventional Raman spectrophotometer includes a laser source, a sample holding system, a wavelength selector, and a detector.
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...