Toward the Realization of Deep-Level Bioimaging without Using Toxic Elements or UV Light
Researchers in Japan developed a silicon fluorescent material that is very low in toxicity and high in luminescence efficiency, compared to conventional materials. Under near-infrared radiation (NIR) at wavelengths of 650 to 1,000 nm—the range known as the “biological optical window”—that is capable of passing through living systems, the joint group succeeded in bioimaging using this new material.
A research group at the National Institute for Materials Science (NIMS) International Center for Materials Nanoarchitectonics (MANA), led by MANA Principal Investigator Françoise Winnik, a MANA postdoc researcher Sourov Chandra, a research group led by MANA Independent Scientist Naoto Shirahata, and a research group consisting of Professor Yoshinobu Baba and Assistant Professor Takao Yasui, Graduate School of Engineering, Nagoya University, jointly developed a silicon fluorescent material that is very low in toxicity and high in luminescence efficiency, compared to conventional materials. Under near-infrared radiation (NIR) at wavelengths of 650 to 1,000 nm—the range known as the “biological optical window”—that is capable of passing through living systems, the joint group succeeded in bioimaging using the new material for the first time in the world.
Fluorescence bioimaging refers to the visualization of cells and other biological tissues that are invisible to the naked eye, by marking them visible with a fluorescent material. The technique enables in vivo observation of the distribution and behavior of living cells in real time. Through application of this technique, it may be feasible to observe the behavior of cells and biomolecules linked to pathogenesis and identify the mechanism of disease development. Many of the conventional fluorescent materials emit light when they react to ultraviolet (UV) light or visible light. However, because biological components such as hemoglobin and body fluids absorb these types of light, they are not applicable for deep-level observation of biological matters. Some fluorescent materials are reactive to light at wavelengths that fall under a “biological optical window,” but most materials have poor luminescent efficiency, and few others with high luminescent efficiency contain toxic elements such as lead and mercury.
Using silicon-based particles, the joint group successfully developed a fluorescent material capable of efficiently producing luminescence by reacting to incoming light at wavelengths comparable to a “biological optical window.” The use of silicon-based fluorescent materials in bioimaging had been previously studied, and some problems were found such as that they need UV light to exert excitation and efficient luminescence, and that they have low light-emitting efficiencies. In view of these issues, the joint research group developed a new core-double shell structure in which crystalline silicon nanoparticles, serving as cores, are coated with hydrocarbon groups and a surfactant. Two‐photon excitation fluorescence imaging demonstrated that crystalline silicon exhibited efficient photoexcitation when absorbing NIR, and that the hydrocarbon groups in the coating increased emission quantum yield. Furthermore, the surfactant coating made the fluorescent material water-soluble. As a result, the new material enabled efficient marking of target biomolecules, and subsequent fluorescent bioimaging of the marked targets using a NIR range of radiation that passes through living systems.
In future studies, we aim to accomplish fluorescent bioimaging at a deep level using the new silicon fluorescent material we developed in this study.
A part of this study was conducted in connection with the “Molecule & Material Synthesis Platform” project at Nagoya University under the “Nanotechnology Platform Japan” program organized by the Ministry of Education, Culture, Sports, Science and Technology.
This study was published in the online version of Nanoscale on April 13, 2016.
“Functional double-shelled silicon nanocrystals for two-photon fluorescence cell imaging: spectral evolution and tuning”; Sourov Chandra, Batu Ghosh, Grégory Beaune, Usharani Nagarajan, Takao Yasui, Jin Nakamura, Tohru Tsuruoka, Yoshinobu Baba, Naoto Shirahata and Françoise M. Winnik; Nanoscale, 2016,8, 9009-9019, DOI: 10.1039/C6NR01437B
Mikiko Tanifuji | Research SEA
Beyond conventional solution-process for 2-D heterostructure
22.06.2018 | Science China Press
Graphene assembled film shows higher thermal conductivity than graphite film
22.06.2018 | Chalmers University of Technology
In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.
Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...
Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...
Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.
Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...
The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.
Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.
An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.
Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...
13.06.2018 | Event News
08.06.2018 | Event News
05.06.2018 | Event News
22.06.2018 | Materials Sciences
22.06.2018 | Earth Sciences
22.06.2018 | Life Sciences