Related Experiment Video
Updated: Jan 23, 2026
06:24
Fluorescent Silver Staining of Proteins in Polyacrylamide Gels
Published on: April 21, 2019
15.1K
Disentangling optically activated delayed fluorescence and upconversion fluorescence in DNA stabilized silver
Stefan Krause1, Cecilia Cerretani1, Tom Vosch1
1Nanoscience Center , Department of Chemistry , University of Copenhagen , Universitetsparken 5 , Copenhagen 2100 , Denmark . Email: stefan.krause@chem.ku.dk ;
Chemical Science
|June 14, 2019
Summary
Optically activated delayed fluorescence (OADF) can be separated from upconversion fluorescence (UCF) using specific near-infrared wavelengths. This separation enables background-free nanoscopy techniques by controlling dark state populations.
Area of Science:
- Biophysics
- Nanotechnology
- Optical Microscopy
Background:
- Optically activated delayed fluorescence (OADF) enables background-free microscopy.
- DNA-stabilized silver nanoclusters (DNA-AgNCs) show OADF often coupled with upconversion fluorescence (UCF).
- UCF arises from a dark state-mediated consecutive photon absorption process.
Purpose of the Study:
- To disentangle OADF and UCF processes.
- To investigate the role of dark states in OADF and UCF.
- To explore background-free nanoscopy applications.
Main Methods:
- Wavelength-dependent near-infrared (NIR) excitation spectroscopy.
- Utilizing DNA-stabilized silver nanoclusters (DNA-AgNCs) as a model system.
- Selective depletion of dark state populations.
Main Results:
- OADF and UCF processes were successfully disentangled.
- Specific secondary NIR excitation wavelengths preferentially deplete dark state populations.
- UCF contribution was minimized by controlling dark state population.
Conclusions:
- Dark state depletion via OADF can minimize UCF.
- This approach may enable background-free STED-like nanoscopy.
- OADF offers a pathway for advanced, high-resolution imaging.
Related Concept Videos
01:53RNA Stability
35.7K
Intact DNA strands can be found in fossils, while scientists sometimes struggle to keep RNA intact under laboratory conditions. The structural variations between RNA and DNA underlie the differences in their stability and longevity. Because DNA is double-stranded, it is inherently more stable. The single-stranded structure of RNA is less stable but also more flexible and can form weak internal bonds. Additionally, most RNAs in the cell are relatively short, while DNA can be up to 250 million...
35.7K
02:24Properties of Enantiomers and Optical Activity
21.5K
It is essential to understand the difference between chiral and achiral interactions and the implications thereof in optical activity and their applications. Just as our feet, which are chiral, interact uniquely with chiral objects, such as a pair of shoes, but identically with achiral socks, enantiomers of a molecule exhibit different properties only when they interact with other chiral media. An example of a significant implication from this facet is the phenomenon known as optical activity,...
21.5K
01:23Photoluminescence: Fluorescence and Phosphorescence
3.6K
Photoluminescence is a process where a molecule absorbs light energy and re-emits it in the form of light. This phenomenon occurs when a substance absorbs photons, promoting its electrons to higher energy level excited states, followed by a relaxation process in which the electrons return to their original ground state energy levels and emit light. Photoluminescence is widely observed in various materials, including semiconductors, and organic and inorganic compounds.
A pair of electrons in a...
A pair of electrons in a...
3.6K
01:29Atomic Fluorescence Spectroscopy
933
Atomic fluorescence spectroscopy (AFS) is an analytical technique that involves the electronic transitions of atoms in a flame, furnace, or plasma being excited by electromagnetic (EM) radiation. When these atoms absorb energy, they become excited and subsequently release energy as they return to their original state. This emitted light, or "fluorescence," is observed at a right angle to the incident beam. Both absorption and emission processes transpire at distinct wavelengths, which...
933
01:16Confocal Fluorescence Microscopy
20.1K
Confocal microscopy is an advanced microscopic technique. The prime advantage of the confocal microscope over other microscopy techniques is its ability to block the out-of-focus light from the illuminated samples using pinholes. It is widely used with fluorescence optics to obtain high-resolution, sharp contrast images. Unlike optical microscopes, confocal microscopes use a focused beam of light laser to scan the entire sample surface at different z-planes. These microscopes are, therefore,...
20.1K
01:26Variables Affecting Phosphorescence and Fluorescence
1.3K
Fluorescence and phosphorescence are essential phenomena in fields like analytical chemistry, biological imaging, and materials science, where they detect molecular properties and visualize cellular structures. Understanding the variables that influence these luminescent behaviors is crucial for maximizing accuracy and efficiency in their applications. These variables can broadly be grouped into chemical structure, solvent properties, and external conditions, each playing a distinct role in...
1.3K