Related Experiment Video
Updated: Jul 20, 2026

Detection of Protein Aggregation using Fluorescence Correlation Spectroscopy
Published on: April 25, 2021
Two-photon fluorescence spectroscopy of individually trapped pseudoisocyanine J-aggregates in aqueous solution
Yoshito Tanaka1, Hiroyuki Yoshikawa, Hiroshi Masuhara
1Department of Applied Physics and Handai Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan.
Abstract:
We have investigated a pseudoisocyanine dye aqueous solution including nanometer-sized J-aggregates by combining optical trapping and two-photon fluorescence spectroscopy. By focusing an intense near-infrared laser into an 8 x 10(-3) M solution, the intense fluorescence from J-aggregates for a few to tens of seconds is observed intermittently, indicating that individual J-aggregates are trapped in and diffuse out from a focal spot. The peak position and full width at half-maximum of the J-band are different from each other. By measuring 171 J-aggregates, it was found that J-aggregates can be classified largely into two groups. The existence of two kinds of groups of J-aggregates could be attributed to the difference in the nucleation process, which is affected by the substrate. J-aggregates possessing a J-band of a narrower bandwidth in a shorter wavelength region are trapped for a longer period of time, indicating that highly ordered J-aggregates are trapped for a longer period of time because of their high polarizability.
More Related Videos
07:56Utilizing Time-Resolved Protein-Induced Fluorescence Enhancement to Identify Stable Local Conformations One α-Synuclein Monomer at a Time
Published on: May 30, 2021
11:34Controlled Synthesis and Fluorescence Tracking of Highly Uniform Poly(N-isopropylacrylamide) Microgels
Published on: September 8, 2016
Related Concept Videos
Protein Dynamics in Living Cells
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Atomic Fluorescence Spectroscopy
Fluorescence and Phosphorescence: Instrumentation
Super-resolution Fluorescence Microscopy
Total Internal Reflection Fluorescence Microscopy