Featured Research

from universities, journals, and other organizations

DNA Molecules Used To Assemble Nanoparticles

Date:
January 31, 2005
Source:
University Of Michigan
Summary:
University of Michigan researchers have developed a faster, more efficient way to produce a wide variety of nanoparticle drug delivery systems, using DNA molecules to bind the particles together.

Dendrimer complex docking on cellular folate receptors.
Credit: Michigan Center for Biologic Nanotechnology

ANN ARBOR, Mich. -- University of Michigan researchers have developed a faster, more efficient way to produce a wide variety of nanoparticle drug delivery systems, using DNA molecules to bind the particles together.

Nanometer-scaled dendrimers can be assembled in many configurations by using attached lengths of single-stranded DNA molecules, which naturally bind to other DNA strands in a highly specific fashion.

"With this approach, you can target a wide variety of molecules---drugs, contrast agents---to almost any cell," said Dr. James R. Baker Jr., the Ruth Dow Doan Professor of Nanotechnology and director of the Center for Biologic Nanotechnology at U-M.

Nanoparticle complexes can be specifically targeted to cancer cells and are small enough to enter a diseased cell, either killing it from within or sending out a signal to identify it. But making the particles is notoriously difficult and time-consuming.

The nanoparticle system used by Baker's lab is based on dendrimers, star-like synthetic polymers that can carry a vast array of molecules on the ends of their arms. It is possible to build a single dendrimer carrying many different kinds of molecules such as contrast agents and drugs, but the synthesis process is long and difficult, requiring months for each new molecule added to the dendrimer in sequential steps. And the yield of useful particles drops with each successive step of synthesis.

For a paper published Jan. 21 in the journal Chemistry and Biology, U-M Biomedical Engineering graduate student Youngseon Choi built nanoparticle clusters of two different functional dendrimers, one designed for imaging and the other for targeting cancer cells. Each of the dendrimers also carried a single-stranded, non-coding DNA synthesized by Choi.

In a solution of two different kinds of single dendrimers, these dangling lengths of DNA, typically 34-66 bases long, found complementary sequences on other dendrimers and knitted together, forming barbell shaped two-dendrimer complexes with folate on one end and fluorescence on the other end.

Folate receptors are over-expressed on the surface of cancer cells, so these dendrimer clusters would tend to flock to the diseased cells. The other end of the complex carries a fluorescent protein so that the researchers can track their movement.

A series of experiments using cell sorters, 3-D microscopes and other tools verified that these dendrimers hit their targets, were admitted into the cells and gave off their signaling light. The self-assembled dendrimer clusters were shown to be well formed and functional.

"This is the proof-of-concept experiment," Choi said. But now that the assembly system has been worked out, other forms of dendrimer clusters are in the works.

"If you wanted to make a therapeutic that targeted five drugs to five different cells, it would be 25 synthesis steps the traditional way," Baker said. At two to three months per synthesis, and a significant loss of yield for each step, that approach just wouldn't be practical.

Instead, the Baker group will create a library of single-functional dendrimers that can be synthesized in parallel, rather than sequentially, and then linked together in many different combinations with the DNA strands.

"So it's like having a shelf full of Tinker Toys," Baker said.

An array of single-functional dendrimers, such as targets, drugs, and contrast agents, and the ability to link them together quickly and easily in many different ways would enable a clinic to offer 25 different "flavors" of dendrimer with only ten synthesis steps, Baker said.

Baker foresees a nanoparticle cluster in which a single dendrimer carries three single-strands of DNA, each with a sequence specific to the DNA attached to other kinds of dendrimers. Put into solution with these other tinker toys, the molecule would self-assemble into a four-dendrimer complex carrying one drug, one target, and one fluorescent.

###

For more information, visit: Nanotechnology in the Life Sciences---http://lifesciences.umich.edu

Center for Biologic Nanotechnology---http://nano.med.umich.edu

U-M Biomedical Engineering---http://www.bme.umich.edu

Chemistry and Biology journal---http://www.chembiol.com


Story Source:

The above story is based on materials provided by University Of Michigan. Note: Materials may be edited for content and length.


Cite This Page:

University Of Michigan. "DNA Molecules Used To Assemble Nanoparticles." ScienceDaily. ScienceDaily, 31 January 2005. <www.sciencedaily.com/releases/2005/01/050123205926.htm>.
University Of Michigan. (2005, January 31). DNA Molecules Used To Assemble Nanoparticles. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2005/01/050123205926.htm
University Of Michigan. "DNA Molecules Used To Assemble Nanoparticles." ScienceDaily. www.sciencedaily.com/releases/2005/01/050123205926.htm (accessed July 25, 2014).

Share This




More Matter & Energy News

Friday, July 25, 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