Featured Research

from universities, journals, and other organizations

Polish Dumpling-Like Particle Has Potential In Drug Delivery

Date:
May 22, 1998
Source:
Washington University In St. Louis
Summary:
Chemists at Washington University in St. Louis have created synthetic polymer particles that are as cute as dumplings. They're called knedels (k-ned-l), after a popular Polish dumpling filled either with meat or sweets. While the Polish knedel is a sumptuous taste treat, the Washington University knedl is a synthetic nano-sized particle that its creators hope someday will be the carrier of drugs or genes for biomedical applications and therapies.

Chemists at Washington University in St. Louis have created synthetic polymer particles that are as cute as dumplings.

They're called knedels (k-ned-l), after a popular Polish dumpling filled either with meat or sweets. While the Polish knedel is a sumptuous taste treat, the Washington University knedl is a synthetic nano-sized particle that its creators hope someday will be the carrier of drugs or genes for biomedical applications and therapies.

Karen Wooley, Ph.D., assistant professor of chemistry at Washington University, recently announced a new breakthrough in the particle that K. Bruce Thurmond, II, a graduate student in Wooley's group, first synthesized in 1996. Wooley and post-doctoral researcher Haiyong Huang, Ph.D., have changed the composition of their knedel's core from a glassy to a rubbery substance similar to the interior of a golf ball. Additionally, this core can be hollowed out, creating a capsule into which large amounts of drugs -- or DNA, for gene therapy -- may be loaded for delivery.

Huang presented a talk on the advance at the Spring Meeting of the American Chemical Society, March 29, in Dallas, TX.

"They're like golf ball molecules in this form" says Wooley. "This advance moves us along in our goal of making knedels potential drug- and gene- carrying systems. It makes the particle a lot more versatile and the rubbery core should allow a higher loading capacity We've gotten lots of interest in the knedels, for their potential, they're novelty, and their name."

The work is funded by the National Science Foundation and Monsanto Company, St. Louis.

Wooley and her colleagues recently have been focusing on the knedel's water-soluble shell that allows them to bind DNA to its surface. This in turn causes small aggregates to form that protect the genetic material from being digested by enzymes. The chemists charge the shell positively so the knedel attracts DNA, which has a negative charge. Thus, the shell itself can play a key role in drug delivery.

Knedels are variations and improvements on a class of polymers -- chain-like structures of repeating compound assemblies -- called micelles. There has been lots of interest this decade in micelles for drug delivery, but they have a major drawback for this purpose. They are dynamic and unstable. If they are diluted or subjected to force in a system, they tend to fall apart.

Knedels, on the other hand, assemble and behave much the way proteins such as insulin do. With insulin, which our pancreas secrete to regulate our blood sugar rates, there are two linear polymer chains of amino acids -- the chemical units that are the building blocks of proteins. The linear chains self-assemble into a three-dimensional structure stabilized by linking with chemical bonds between two residues of amino acids. These cross-linkings hold everything together.

The knedel is constructed in a similar fashion. Wooley and her colleagues form a polymer micelle composed of as few as 10 to several hundred chains, assembled into a glassy sphere with a core that does not mix with the shell or the outer environment. Chemical reactions within the shell bind the chains together and give the stabilized, cross-linked structure.

"The knedel is a very simple approach that offers versatility for composition of the particles," she says. "We can control the size of the core, the thickness of the shell and the overall size of particles as well as the core and shell compositions. This will enable us to control the properties and function of the particles in their environment."

Originally Wooley and her group placed polystyrene -- the basic stuff of which disposable coffee cups are made -- into the core, but found it was too inflexible. They could not place material into the core unless a solvent was used. The new core is made of a more flexible material, polyisoprene, which has cross-linking capabilities that give the structure its rubbery property.

Wooley has future plans of incorporating degradable polymers into the knedel structure. She and graduate students Jennifer Weinberg and Min Wang have developed new degradable polymers that they can time to fall apart in water anywhere from a few minutes to a few months. Adding this feature to a drug-bearing knedel would give the particle the ability to be time-released.

Wooley also is working on modifications to the knedel's shell. She wants to make it flexible so that when it comes into contact with proteins, the shell won't cause proteins to stick and denature, which is an altering of molecular structure.

As for that name: After Wooley and her group constructed the polymer particles, they tried to see them with a standard electron microscope, but the particles were too small. They turned to colleague Tomasz Kowalewski, Ph.D., research assistant professor of chemistry at Washington University, a Polish native who is an expert in atomic force microscopy (AFM), and operates one at Washington University. This microscope is a new, powerful tool that can visualize nature's tiniest objects.

"Tomasz said, 'Oh, they look like knedels. You must call them that', And that's how they got their name," Wooley says.


Story Source:

The above story is based on materials provided by Washington University In St. Louis. Note: Materials may be edited for content and length.


Cite This Page:

Washington University In St. Louis. "Polish Dumpling-Like Particle Has Potential In Drug Delivery." ScienceDaily. ScienceDaily, 22 May 1998. <www.sciencedaily.com/releases/1998/05/980522082239.htm>.
Washington University In St. Louis. (1998, May 22). Polish Dumpling-Like Particle Has Potential In Drug Delivery. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/1998/05/980522082239.htm
Washington University In St. Louis. "Polish Dumpling-Like Particle Has Potential In Drug Delivery." ScienceDaily. www.sciencedaily.com/releases/1998/05/980522082239.htm (accessed July 23, 2014).

Share This




More Matter & Energy News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com
Boeing Ups Outlook on 52% Profit Jump

Boeing Ups Outlook on 52% Profit Jump

Reuters - Business Video Online (July 23, 2014) Commercial aircraft deliveries rose seven percent at Boeing, prompting the aerospace company to boost full-year profit guidance- though quarterly revenues missed analyst estimates. Bobbi Rebell reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Car Market on the Rebound?

Europe's Car Market on the Rebound?

Reuters - Business Video Online (July 23, 2014) Daimler kicks off a round of second-quarter earnings results from Europe's top carmakers with a healthy set of numbers - prompting hopes that stronger sales in Europe will counter weakness in emerging markets. Hayley Platt reports. Video provided by Reuters
Powered by NewsLook.com
9/11 Commission Members Warn of Terror "fatigue" Among American Public

9/11 Commission Members Warn of Terror "fatigue" Among American Public

Reuters - US Online Video (July 22, 2014) Ten years after releasing its initial report, members of the 9/11 Commission warn of the "waning sense of urgency" in combating terrorists attacks. Mana Rabiee reports. Video provided by Reuters
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