Related Experiment Video
Updated: Sep 1, 2025
13:39
Optical Trapping of Nanoparticles
Published on: January 15, 2013
22.5K
Characterization of nanoparticle size distributions using a microfluidic device with integrated optical
Kiana Malmir1, William Okell1, Aurélien A P Trichet2
1Oxford University, Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK. kianamalmir@gmail.com.
Lab on a Chip
|August 15, 2022
Summary
We developed a new method to analyze nanoparticle physical properties in fluids using optical microcavities. This technique measures particle size by detecting the interplay between viscous drag and optical forces, aiding nanomedicine applications.
Area of Science:
- Physics
- Nanotechnology
- Biomedical Engineering
Background:
- Accurate characterization of nanoparticles is crucial for applications in nanomedicine.
- Existing optical sorting methods have limitations in the size range of interest for nanomedicine.
Purpose of the Study:
- To introduce a novel method for analyzing nanoparticle physical properties in fluids.
- To enable precise size characterization of nanoparticles relevant to nanomedicine.
Main Methods:
- Utilizing a microfluidic device with integrated optical microcavities.
- Analyzing the competition between viscous drag and optical forces on nanoparticles.
- Measuring particle size via dielectric polarizability per unit radius derived from detection event duration.
Main Results:
- Successfully characterized polymer particles with diameters as small as 140 nm.
- Demonstrated a technique applicable to nanoparticle sizes below previous optical sorting thresholds.
- Validated the use of optical microcavities as combined traps and sensors.
Conclusions:
- The developed method offers a new approach for detailed physical characterization of nanoparticles in solution.
- This technique is particularly relevant for nanoparticle analysis in the nanomedicine size range.
- Potential for integration with other analytical methods for comprehensive particle characterization.
