Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Nanomedicine: Bringing brighter light into living bodies

19.07.2012
Fluorescent dyes with aggregation-induced emission provide new probes for cancer diagnosis and therapy

Fluorescent nanoparticles loaded with organic light-emitting dyes are expected to transform live-animal imaging technologies. Compared to inorganic quantum dots, these optically stable materials are non-toxic and can easily be modified with functional groups, making them ideal when targeting specific tissues in the body. Unfortunately, traditional dyes have been known to aggregate and lose their emission intensity when incorporated in nanoparticles at high concentration.

To overcome this problem, a team of researchers led by Bin Liu and Ben Zhong Tang at the A*STAR Institute of Materials Research and Engineering have now designed a family of dyes with enhanced fluorescence upon aggregation.

At the heart of the traditional dyes is a planar chromophore called triphenylamine-modified dicyanomethylene, which emits red light in dilute solutions but fluoresces weakly when aggregated. “The close vicinity of the chromophores induces fluorescence quenching due to non-radiative pathways,” says Liu.

Liu, Tang and their team reversed this phenomenon by attaching propeller-shaped tetraphenylethene pendants to each extremity of the chromophore. Contrary to planar compounds, the shape of the propellers prevents strong stacking interactions between chromophores, blocking the aggregation-caused quenching process. In addition, the physical confinement prevents these propellers from rotating freely, enabling light emission.

The team formulated the dyes using a bovine serum albumin (BSA) matrix — a biocompatible and clinically used polymer — and evaluated their performance as probes. Experimental characterization showed that the wavelength of the emission maximum of the nanoparticles remained unchanged upon encapsulation and that the intensity of the emitted light increased with the dye loading.

Live imaging of breast cancer cells revealed that the nanoparticles displayed more intense and homogeneously distributed red fluorescence in the cytoplasms (see image) than free aggregates, suggesting that BSA boosted the cellular uptake of the dyes. The team also found that the nanoparticles were optically stable in biological media and displayed good biocompatibility.

The researchers intravenously injected the nanoparticles in liver-tumor-bearing mice for in vivo imaging studies. They found that unlike free aggregates, the nanoparticles selectively accumulated in the tumor, clearly highlighting the cancerous tissue in the animals. “This demonstration underscores new research opportunities to explore similar diagnostic probes with potential clinical applications,” says Liu.

The team is currently investigating near-infrared emissive biological probes for targeted in vivo tumor imaging applications. The nanoparticles can also be utilized to understand cancer metastasis or the fate of transplanted stem cells. “These probes are promising in multimodal imaging applications through integration with magnetic resonance imaging or nuclear imaging reagents,” says Liu.

The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering

References:
Qin, W. et al. Biocompatible nanoparticles with aggregation-induced emission characteristics as far-red/near-infrared fluorescent bioprobes for in vitro and in vivo imaging applications. Advanced Functional Materials 22, 771–779 (2012).

A*STAR Research | Research asia research news
Further information:
http://www.a-star.edu.sg
http://www.researchsea.com

More articles from Health and Medicine:

nachricht Diabetes mellitus: A risk factor for early colorectal cancer
27.05.2020 | Nationales Centrum für Tumorerkrankungen (NCT) Heidelberg

nachricht Ultra-thin fibres designed to protect nerves after brain surgery
27.05.2020 | Martin-Luther-Universität Halle-Wittenberg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Biotechnology: Triggered by light, a novel way to switch on an enzyme

In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".

Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...

Im Focus: New double-contrast technique picks up small tumors on MRI

Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.

researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

 
Latest News

New 5G switch provides 50 times more energy efficiency than currently exists

27.05.2020 | Information Technology

Return of the Blob: Surprise link found to edge turbulence in fusion plasma

27.05.2020 | Physics and Astronomy

Upwards with the “bubble shuttle”: How sea floor microbes get involved with methane reduction in the water column

27.05.2020 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>