Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Implants that Respond to Your Body

04.08.2009
Dynamic, 3D Pattern Formation within Protein-based Gels

Modern regenerative medicine is on the lookout for implantable materials that can change as the surrounding tissue does, and two Stanford University researchers have made some new gel materials that do just that.

Karin Straley and Professor Sarah Heilshorn have developed a method for preparing protein-based implant materials that can evolve with the changing needs of the host biological system. Not only can their new materials change in different ways at different times, they can do so at different places within the implant materials.

The materials, of a type known as hydrogels, are prepared from connected blocks of assorted designer proteins. Certain parts of some blocks degrade on exposure to specific enzymes, creating a three-dimensional pattern throughout the gel. If the gels are in a biological system and the triggering enzymes are selected to be ones produced by the system at a certain place and rate, the pattern evolves in response to the biochemistry of the system.

And, as a bonus for medical treatment, “we also demonstrated that the material released during this pattern formation can be modified to serve as a drug-delivery vehicle, enabling the release of multiple small molecules with distinct spatial and temporal delivery profiles,” states Prof. Heilshorn.

It seems the designer proteins were the key to the technological breakthrough. The proteins were prepared as block copolymers, which could then be crosslinked to form a hydrogel. Genetic templates were used to synthesize the protein-polymers, allowing precise, molecular level control over their content. This control enabled the Stanford researchers to develop hydrogels that were initially stable and subject to the usual gel mechanisms, and also to finely tune the degradation rates of selected components on exposure to the relevant proteases.

The new structures could contain completely internal voids or be open, connected geometries. Adding and removing material was no problem as both the protease enzymes that cause the degradation and the degraded material fragments diffuse readily through the hydrogel structure.

When asked to describe the possibilities presented by the work, Prof. Heilshorn explained: “As an application of this technology, a materials scientist can design a single medical implant to meet two or more separate sets of sequential, optimization criteria. For example, initially the implant should have mechanical properties that enable easy surgical implantation, such as a bulk slab of material that can be sutured into place without disturbing any delicate micro- or nanopatterns. Then after implantation, the locally secreted enzymes can remodel the material to create tunnels that may promote the growth of blood vessels into the implant [which then becomes a tissue scaffold]. Finally, the enzymes secreted by the blood vessels may trigger development of a porous 3D pattern to stimulate the infiltration of other cell types into the new tissue.

In the future, these scaffolds are envisioned as a means to enable “two-way” communication between cells and engineered biomaterials. For example, encapsulated stem cells will initially secrete a specific set of enzymes that could trigger the release of drugs to induce differentiation into a specialized cell type. These newly specialized cells will alter their secreted enzymes, turning off delivery of the differentiation drugs and turning on delivery of a new set of therapeutic drugs. Therefore, these biomaterials provide cells with a dynamic environment that can respond to fluctuations in cell and tissue biochemistry.”

The work was largely supported by a grant through the National Academies Keck Futures Initiative and is published in Advanced Materials.

“Dynamic, Three-Dimensional Pattern Formation within Enzyme-Responsive Hydrogels”

K. S. Straley and S. C. Heilshorn, Advanced Materials, 2009, DOI: 10.1002/adma.200901865

Available online at http://doi.wiley.com/10.1002/adma.200901865 on August 4, 2009.

Direct Contact: Sarah Heilshorn, Assistant Professor

Materials Science and Engineering
Stanford University
http://www.stanford.edu/group/heilshorn

Carmen Teutsch | Wiley-VCH Verlag
Further information:
http://www.wiley-vch.de
http://doi.wiley.com/10.1002/adma.200901865
http://www.stanford.edu/group/heilshorn

More articles from Materials Sciences:

nachricht Scientists announce the quest for high-index materials
24.07.2017 | Moscow Institute of Physics and Technology

nachricht ADIR Project: Lasers Recover Valuable Materials
24.07.2017 | Fraunhofer-Institut für Lasertechnik ILT

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

Ultrathin device harvests electricity from human motion

24.07.2017 | Power and Electrical Engineering

Scientists announce the quest for high-index materials

24.07.2017 | Materials Sciences

ADIR Project: Lasers Recover Valuable Materials

24.07.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>