Featured Research

from universities, journals, and other organizations

Mimicking biological complexity, in a tiny particle

Date:
August 17, 2011
Source:
Massachusetts Institute of Technology
Summary:
Tiny particles made of polymers hold great promise for targeted delivery of drugs and as structural scaffolds for building artificial tissues. However, current production methods for such microparticles yield a limited array of shapes and can only be made with certain materials, restricting their usefulness. New technology could lead to better drug delivery and artificial tissues that imitate natural tissue.

Using a temperature-responsive micromold, MIT engineers created two-layer gel microparticles (the red and green areas represent separate layers).
Credit: Halil Tekin

Tiny particles made of polymers hold great promise for targeted delivery of drugs and as structural scaffolds for building artificial tissues. However, current production methods for such microparticles yield a limited array of shapes and can only be made with certain materials, restricting their usefulness.

Related Articles


In an advance that could broadly expand the possible applications for such particles, MIT engineers have developed a way to make microparticles of nearly any shape, using a micromold that changes shape in response to temperature. They can also precisely place drugs into different compartments of the particles, making it easier to control the timing of drug release, or arrange different cells into layers to create tissue that closely mimics the structure of natural tissues.

The new technique, described in a paper published online July 18 in the Journal of the American Chemical Society, also allows researchers to create microparticles from a much more diverse range of materials, says Halil Tekin, an MIT graduate student in electrical engineering and computer science and lead author of the paper.

Currently, most drug-delivering particles and cell-encapsulating microgels are created using photolithography, which relies on ultraviolet light to transform liquid polymers into a solid gel. However, this technique can be used only with certain materials, such as polyethylene glycol (PEG), and the ultraviolet light may harm cells.

Another way to create microparticles is to fill a tiny mold with a liquid gel carrying drug molecules or cells, then cool it until it sets into the desired shape. However, this does not allow for creation of multiple layers.

The MIT research team, led by Ali Khademhosseini, associate professor in the MIT-Harvard Division of Health Sciences and Technology, and Robert Langer, the David H. Koch Institute Professor, overcame that obstacle by building micromolds out of a temperature-sensitive material that shrinks when heated.

The mold is first filled with a liquid gel that contains one kind of cell or drug. After the gel has solidified, the mold is heated so the walls surrounding the solid gel shrink, pulling away from the gel and creating extra space for a second layer to be added. The system could also be modified to incorporate additional layers, Tekin says.

"The method is quite creative," says Michael Sefton, professor at the University of Toronto Institute of Biomaterials and Biomedical Engineering, who was not involved in this project. "It offers the opportunity to make multilayer microstructures. The next step is figuring out what you can do with these two-layer structures."

Artificial tissue

So far, the researchers have created cylindrical and cubic particles, as well as long striped particles, and many other shapes should be possible, Tekin says. Their starting material was a gel made of agarose, a type of sugar.

The long striped particles would be particularly useful for engineering elongated tissues such as cardiac tissue, skeletal muscle or neural tissue. In this study, the researchers created striped particles with a first layer of fibroblasts (cells found in connective tissue), surrounded by a layer of endothelial cells, which form blood vessels. Researchers also created cubic and cylindrical particles in which liver cells were encapsulated in the first layer, surrounded by a layer of endothelial cells. This arrangement could accurately replicate liver tissue.

Such gels could also be embedded with proteins that help the cells orient themselves in a desired structure, such as a tube that could form a capillary. The researchers are also planning to create particles that contain collagen, which constitutes much of the body's structural tissues, including cartilage.

Eventually, the researchers hope to use this technique to build large tissues and even entire organs. Such tissues could be used in the laboratory to test potential new drugs. "If you can create 3-D tissues which are functional and really mimicking the native tissue, they are going to give the right responses to drugs," Tekin says.

This could speed up the drug discovery process and decrease the costs, because fewer animal experiments would be needed, he says.


Story Source:

The above story is based on materials provided by Massachusetts Institute of Technology. Note: Materials may be edited for content and length.


Journal Reference:

  1. Halil Tekin, Tonia Tsinman, Jefferson G. Sanchez, Brianna J. Jones, Gulden Camci-Unal, Jason W. Nichol, Robert Langer, Ali Khademhosseini. Responsive Micromolds for Sequential Patterning of Hydrogel Microstructures. Journal of the American Chemical Society, 2011; 110803122422024 DOI: 10.1021/ja204266a

Cite This Page:

Massachusetts Institute of Technology. "Mimicking biological complexity, in a tiny particle." ScienceDaily. ScienceDaily, 17 August 2011. <www.sciencedaily.com/releases/2011/08/110816112648.htm>.
Massachusetts Institute of Technology. (2011, August 17). Mimicking biological complexity, in a tiny particle. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2011/08/110816112648.htm
Massachusetts Institute of Technology. "Mimicking biological complexity, in a tiny particle." ScienceDaily. www.sciencedaily.com/releases/2011/08/110816112648.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
Anglerfish Rarely Seen In Its Habitat Will Haunt You

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Newsy (Nov. 22, 2014) For the first time Monterey Bay Aquarium recorded a video of the elusive, creepy and rarely seen anglerfish. Video provided by Newsy
Powered by NewsLook.com
Birds Around the World Take Flight

Birds Around the World Take Flight

Reuters - Light News Video Online (Nov. 22, 2014) An imperial eagle equipped with a camera spreads its wings over London. It's just one of the many birds making headlines in this week's "animal roundup". Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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