Chemical reactions that create durable bonds between cells and fluorescent dyes are an attractive way to monitor biological functions in the body. However, they can also detrimentally modify key chemical groups on cell surfaces.
Chemically binding fluorescent dyes to cells—with minimal impact on their original function—is now possible, thanks to a site-selective reaction developed by a team led by Yasuyoshi Watanabe and Tsuyoshi Tahara from the RIKEN Center for Molecular Imaging Science, Kobe¹.
Working closely with Katsunori Tanaka and Koichi Fukase from Osaka University, the researchers decided to use organic compounds called aldehydes as dye precursors as they readily react with nitrogen-containing functionalities, or amino groups, exposed at protein surfaces.
To assess the efficacy of their method, the team mixed the aldehydes with brain cancer cells in vitro for 10 minutes then compared them with typical amino reactive dye precursors known as succinimidyl esters (NHS) (Fig. 1). They discovered that the aldehyde precursors produced brighter fluorescence than the NHS dyes.
Confocal microscopy showed that the aldehydes reacted with amino groups of lysine amino acid residues on the cell surface and those of other cell membrane components, whereas the NHS dyes penetrated the cells. They confirmed this by treating the labeled cells with detergent: the aldehyde-derived labels washed off the cell surface, whereas their NHS counterparts remained in the cells. The aldehyde-derived labels also remained effective at exceptionally low concentrations, unlike the NHS-derived labels.
“In contrast to pre-existing cell labeling protocols, this reaction tightly anchors the labels to the surface of living cells within 10 minutes at 10 nM [dye] concentrations and with a very simple ‘kit-like’ operation,” say Watanabe and Tahara. The team also observed that the brain cells maintained their ability to undergo cell division after labeling because of the mild reaction conditions.
The researchers also labeled lymphocytes, extracted from mice, with the fluorescent dyes and injected them into live mice for in vivo monitoring. They found that the labels clearly highlighted the trafficking of the cells into the organs of the mouse immune system. In particular, they noted that the cells gradually accumulated in the spleen and intestinal lymph nodes in six hours before disappearing from the spleen.
In addition to investigating potential clinical applications, the team is currently planning to apply their method to the synthesis of metal binding labels to introduce radioactive and magnetic properties into cells for imaging techniques such as positron emission tomography and magnetic resonance imaging.The corresponding author for this highlight is based at the Molecular Probe Dynamics Laboratory, RIKEN Center for Molecular
gro-pr | Research asia research news
Unique genome architectures after fertilisation in single-cell embryos
30.03.2017 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
Transport of molecular motors into cilia
28.03.2017 | Aarhus University
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
30.03.2017 | Health and Medicine
30.03.2017 | Health and Medicine
30.03.2017 | Medical Engineering