Progress Toward Artificial Tissue?

May 15, 2009

(PhysOrg.com) -- For modern implants and the growth of artificial tissue and organs, it is important to generate materials with characteristics that closely emulate nature.

However, the tissue in our bodies has a combination of traits that are very hard to recreate in synthetic materials: It is both soft and very tough.

A team of Australian and Korean researchers led by Geoffrey M. Spinks and Seon Jeong Kim has now developed a novel, highly porous, sponge-like material whose mechanical properties closely resemble those of biological soft tissues. As reported in the journal Angewandte Chemie, it consists of a robust network of DNA strands and carbon nanotubes.

, such as tendons, muscles, arteries, and skin or other organs, obtain their mechanical support from the extracellular matrix, a network of protein-based nanofibers. Different protein morphologies in the extracellular matrix produce tissue with a wide range of stiffness. Implants and scaffolding for require porous, soft materials -- which are usually very fragile. Because many biological tissues are regularly subjected to intense mechanical loads, it is also important that the implant material have comparable elasticity in order to avoid inflammation. At the same time, the material must be very strong and resilient, or it may give out.

The new concept uses as a matrix; the strands completely “wrap” the scaffold-forming carbon nanotubes in the presence of an ionic liquid, networking them to form a gel. This gel can be spun: just as silk and synthetic fibers can be wet-spun for textiles, the gel can be made into very fine threads when injected into a special bath. The dried fibers have a porous, sponge-like structure and consist of a network of intertwined 50 nm-wide nanofibers. Soaking in a calcium chloride solution further cross-links the DNA, causing the fibers to become denser and more strongly connected.

These spongy fibers resemble the collagen fiber networks of the biological extracellular matrix. They can also be knotted, braided, or woven into textile-like structures. This results in materials that are as elastic as the softest natural tissues while simultaneously deriving great strength from the robust DNA links.

An additional advantage is the electrical conductivity of the new material, which can thus also be used in electrodes for mechanical actuators, energy storage, and sensors. For example, the researchers were able to produce a hydrogen peroxide sensor. The carbon nanotubes catalyze the oxidation of hydrogen peroxide, which results in a measurable current. Hydrogen peroxide plays a role in normal heart function and certain heart diseases. A robust sensor with elasticity similar to the heart muscle would be of great help in researching these relationships.

More information: Geoffrey M. Spinks, University of Wollongong (Australia), Tough Supersoft Sponge Fibers with Tunable Stiffness from a DNA Self-Assembly Technique, Angewandte Chemie International Edition, doi: 10.1002/anie.200804788

Provided by Wiley (news : web)

Explore further: Scientists come closer to the industrial synthesis of a material harder than diamond

add to favorites email to friend print save as pdf

Related Stories

Proteins as Parents

Jul 31, 2006

So that we can move, and so that our heart beats, we need proteins with special mechanical properties, "molecular springs", which give our tissues the necessary strength and take care of elasticity and tensibility.

Coming Soon: Blood Vessels from a Test Tube?

Jun 04, 2007

Our tissues and organs consist of a complex, closely balanced assembly of different types of cells, extracellular matrix, and special signal-carrying molecules. The growth of such structures in the laboratory, perhaps for ...

Protein Fibrils as Alternative Plastics?

May 28, 2008

Amyloid deposits in tissues and organs are linked to a number of diseases, including Alzheimer’s, Parkinson’s, type II diabetes, and prion diseases such as BSE. However, amyloids are not just pathological substances; ...

Nanotubes inspire new technique for healing broken bones

Jul 07, 2005

Scientists have shown for the first time that carbon nanotubes make an ideal scaffold for the growth of bone tissue. The new technique could change the way doctors treat broken bones, allowing them to simply inject a solution ...

Engineers 'bone' up on biological materials

May 07, 2008

In a recent feature article published in Materials Research Society's Bulletin, Dr Michelle Oyen explores the potential uses of synthetic bone-like material. Michelle suggests that these materials will be too ...

Recommended for you

'Small' transformation yields big changes

Sep 15, 2014

An interdisciplinary team of researchers led by Northeastern University has developed a novel method for controllably constructing precise inter-nanotube junctions and a variety of nanocarbon structures in ...

Aligned carbon nanotube / graphene sandwiches

Sep 12, 2014

By in situ nitrogen doping and structural hybridization of carbon nanotubes (CNTs) and graphene via a two-step chemical vapor deposition (CVD), scientists have fabricated nitrogen-doped aligned carbon nanotu ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

wawadave
not rated yet May 15, 2009
This will have many useful applications.