Featured Research

from universities, journals, and other organizations

Bioimaging: Aim for the stars

Date:
October 25, 2012
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
Glucose–amine rings turn star-shaped fluorescent dyes into powerful probes for imaging cancer cells in three dimensions.

A new fluorescent glucose-amine probe can make identification of cancer cells (green) using two-photon microscopy easier and safer.
Credit: 2012 Guan Wang

Glucose-amine rings turn star-shaped fluorescent dyes into powerful probes for imaging cancer cells in three dimensions.Early detection of soft-tissue diseases, such as breast cancer, typically requires invasive biopsies. Now, a new self-assembled nanoparticle developed by Bin Liu at the A*STAR Institute of Materials Research and Engineering and co-workers may soon make biopsies obsolete. The team's material significantly enhances the safety of two-photon microscopy (TPM) -- a technique that uses fluorescent probes to generate three-dimensional pictures of cancer cell structures in living tissue.

Although TPM provides deep access to cell tissue without significant photo-damage, finding suitable substances to act as light-emitting probes is challenging. 'Quantum dots' made from nanoscale aggregates of elements such as cadmium and selenium are excellent cell-structure illuminators, thanks to their bright and stable fluorescence. However, their inherent toxicity restricts many possible biological applications.

Liu and her team therefore turned to conjugated organic molecules to produce less toxic dyes for TPM. While such small organic molecules are normally unable to absorb sufficient amounts of laser light to initiate fluorescence imaging, the team resolved this problem by synthesizing a star-shaped material known as a dendrimer. Consisting of a central triphenyl amine core and three 'arms' made from extended conjugated chains, this unique geometry can induce much larger cross sections that can absorb two-photons better than isolated fluorescent dyes.

To ensure biocompatibility between the star-shaped dendrimer and cell tissue, the researchers had to employ a chemical trick. Inspired by the versatile binding behavior of chitosan, a natural polysaccharide, the team used a mild bromide-thiol reaction to attach several glucose-amine sugar rings to the dendrimer's arms. According to Liu, this process lowered the cytotoxicity of the dye and enabled them to functionalize it with folic acid ligands that target the surfaces of a breast cancer cell line known as MCF-7.

The team's experiments showed that the dendritic dye self-assembled into dispersed nanoparticles when submerged in water -- a form that increases two-photon-absorption cross sections and provides a high yield of laser-induced fluorescence. When they incubated these nanoparticles into the MCF-7 cells, subsequent TPM imaging revealed a bright fluorescence localized inside the cancer cell cytoplasma (see image). This data indicates that specific binding occurs between the dendritic dye and folate receptors on the MCF-7 surface.

Cell viabilities close to 100% at dye concentrations used for imaging studies confirms that this strategy is a safe and promising way to increase the use of TPM imaging. "We are keen to expand the current in vitro imaging to in vivo applications," notes Liu.

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


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Guan Wang, Xinhai Zhang, Junlong Geng, Kai Li, Dan Ding, Kan-Yi Pu, Liping Cai, Yee-Hing Lai, Bin Liu. Glycosylated Star-Shaped Conjugated Oligomers for Targeted Two-Photon Fluorescence Imaging. Chemistry - A European Journal, 2012; 18 (31): 9705 DOI: 10.1002/chem.201200849

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Bioimaging: Aim for the stars." ScienceDaily. ScienceDaily, 25 October 2012. <www.sciencedaily.com/releases/2012/10/121025160856.htm>.
The Agency for Science, Technology and Research (A*STAR). (2012, October 25). Bioimaging: Aim for the stars. ScienceDaily. Retrieved July 26, 2014 from www.sciencedaily.com/releases/2012/10/121025160856.htm
The Agency for Science, Technology and Research (A*STAR). "Bioimaging: Aim for the stars." ScienceDaily. www.sciencedaily.com/releases/2012/10/121025160856.htm (accessed July 26, 2014).

Share This




More Matter & Energy News

Saturday, July 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins