Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Implants that Respond to Your Body

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 on August 4, 2009.

Direct Contact: Sarah Heilshorn, Assistant Professor

Materials Science and Engineering
Stanford University

Carmen Teutsch | Wiley-VCH Verlag
Further information:

More articles from Materials Sciences:

nachricht For graphite pellets, just add elbow grease
23.03.2018 | Rice University

nachricht Sensitive grip
23.03.2018 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

For graphite pellets, just add elbow grease

23.03.2018 | Materials Sciences

Unique communication strategy discovered in stem cell pathway controlling plant growth

23.03.2018 | Agricultural and Forestry Science

Sharpening the X-ray view of the nanocosm

23.03.2018 | Physics and Astronomy

Science & Research
Overview of more VideoLinks >>>