Nanoparticles Create Biocompatible Capsules

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Nanoparticles Create Biocompatible Capsules

http://www.medicalnewstoday.com/medicalnews.php?newsid=39017

An innovative strategy of mixing lipids and nanoparticles to produce

new drug and agricultural materials and delivery vehicles has been

developed by researchers at the University of Illinois at Urbana-

Champaign.

" This is a new way to make nano-size capsules of a biologically

friendly material, " said Steve Granick, a professor of materials

science and engineering, chemistry and physics. " The hollow,

deformable and biofunctional capsules could be used in drug delivery,

colloidal-based biosensors and enzyme-catalyzed reactions. "

Lipids are the building blocks of cell membranes. The construction of

useful artificial lipid vesicles was previously not possible, because

the vesicles were too delicate. Granick and graduate student

Liangfang Zhang found a way to stabilize lipids and stop their

destruction. The researchers describe their technique in a paper

accepted for publication in the journal Nano Letters, and posted on

its Web site.

To stabilize lipids, the researchers begin by preparing a dilute

solution of lipid capsules of a particular size. After encapsulating

chemicals in the capsules or adsorbing molecules on their surfaces,

they add charged nanoparticles to the solution. The nanoparticles

adhere to the capsules and prevent further growth, freezing them at

the desired size. The lipid concentration can then be increased

without limits.

" We form an 'army' of uniform capsules, and then we can use them in a

military fashion, " said Granick, who also is a researcher at the

Frederick Seitz Materials Research Laboratory and at the Beckman

Institute for Advanced Science and Technology. " That is, the capsules

are well behaved, and follow orders without wandering off and

propagating. "

As proof of concept, Granick and Zhang encapsulated fluorescent dyes

within lipid capsules. No leakage occurred, and the lipids proved

stable against further fusion.

" This opens the door to using biologically friendly capsule delivery

vehicles in exciting new health and agricultural applications, "

Granick said. " Chemical reactions can be performed within individual

isolated capsules, or on groups of capsules linked together like

boxcars in a train. "

The biocompatible containers could carry cargo such as enzymes, DNA,

proteins and drug molecules throughout living organisms. They could

also serve as surrogate factories where enzyme-catalyzed reactions

are performed. By attaching biomolecules to the capsule's surface,

novel colloidal-size sensors could be produced.

An additional use for stabilized lipid capsules is the study of drug

behavior. " A drug contained in this nano environment is like a fish

swimming inside a bowl, " Granick said. " We can study the 'fish' in

detail, and it won't swim away. "