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Dual-Color Fluorescence Cross-Correlation Spectroscopy to Study Protein-Protein Interaction and Protein Dynamics in Live Cells
Published on: December 11, 2021
Two-photon fluorescence correlation spectroscopy through a dual-clad optical fiber
Yu-Chung Chang1, Jing Yong Ye, Thommey Thomas
1Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Blvd., Ann Arbor, MI 48109-2099, USA. ycchang@umich.edu
Optics Express
|August 20, 2008
Summary
This study introduces a novel dual-clad optical fiber system for ultrasensitive two-photon fluorescence correlation spectroscopy (FCS). The innovative fiber design enables highly efficient detection of nanoparticles, including fluorescent nanospheres and quantum dots.
Area of Science:
- Optics and Photonics
- Biophysics
- Materials Science
Background:
- Fluorescence Correlation Spectroscopy (FCS) is a powerful technique for studying molecular dynamics.
- Traditional FCS setups can be limited by excitation and collection efficiency.
- Two-photon excitation offers advantages for reduced photobleaching and enhanced spatial resolution.
Purpose of the Study:
- To develop and validate a dual-clad optical fiber system for ultrasensitive two-photon excited fluorescence correlation spectroscopy (FCS).
- To demonstrate the capability of the system for detecting small fluorescent nanoparticles.
Main Methods:
- Utilized a dual-clad optical fiber with a single-mode core for prechirped ultrafast pulse delivery.
- Leveraged the larger numerical aperture of the inner cladding for enhanced fluorescence collection.
- Employed two-photon excited fluorescence correlation spectroscopy (FCS).
Main Results:
- Achieved high excitation and fluorescence collection efficiency using the dual-clad fiber.
- Demonstrated ultrasensitive detection of fluorescent nanospheres (12 nm radius) and quantum dots (7 nm radius).
- Obtained particle sizes consistent with commercial dynamic light scattering (DLS) measurements.
Conclusions:
- The dual-clad optical fiber is critical for achieving ultrasensitive two-photon fluorescence detection in FCS.
- This fiber-based FCS system offers a promising platform for high-sensitivity nanoparticle characterization.
- The system provides accurate size measurements for nanoparticles, validated by DLS.
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