Innovative concept for knee cartilage treatment

Oct 09, 2013
Heated by movement, nanostructures in the hydrogel matrix let go of the drugs it contains. Credit: EPFL

Researchers have developed a material that can be used for the controlled release of a substance when subjected to cyclic mechanical loading. This work, carried out within the context of the National Research Programme "Smart Materials" (NRP 62), offers a potential treatment method for specific tissues such as knee cartilage.

In order to regenerate, , paradoxically, needs to be placed under mechanical stress, as happens whenever we take a step and our knees take our weight. When stimulated in this way, the develop receptors that are sensitive to the growth factors produced by the organism. It is also at this very moment that they would be most receptive to medication. Working on this basis, Dominique Pioletti and Harm-Anton Klok from EPF Lausanne have developed a smart material that only releases a substance when the material is mechanically loaded.

Threshold effect

As they describe in a recent publication, their material takes the form of a hydrogel matrix, liposome-type nanoparticles and, finally, a payload – in this case a dye. When subjected to cyclic , the hydrogel matrix heats up. Once subjected to heat, the diameter of the liposomes shrinks significantly. This frees up space in the matrix, increasing its permeability and facilitating the release of the dye from the matrix. "One of the main difficulties has been the development of nanoparticles that respond to our specification," explains Dominique Pioletti. "Basically, for the concept to work, their response to the heating process must have a very clear threshold between the two to three degrees that separate the static and stimulated states."

The researchers then wanted to verify that it was actually the heating process resulting from the repetition of the mechanical loading that caused the dye to be released. During an initial experiment, the material was subjected to cyclic mechanical loading but the heat produced was evacuated in order to prevent any local temperature increase in the material. "This test enabled us to exclude a sponge-type function, whereby the dye was only being released as a result of the pressure," explains Dominique Pioletti. During a second experiment, the nanoparticles were removed. The heated up as expected due to the cyclic mechanical loading but none of the was released. The researchers concluded that the three elements of the composite material were required for the system as a whole to function as intended.

Long-term prospects

Whilst the researchers have been able to demonstrate the validity of their concept, Dominique Pioletti stresses that a future treatment is still a long way off. "First of all we need to develop a hydrogel and that are safe and biodegradable, before progressing to clinical trials. And, above all, we need to find partners interested in investing in our project."

Explore further: Researchers bring clean energy a step closer

More information: Moghadam, M. et al. (2013) Controlled release from a mechanically-stimulated thermosensitive self-heating composite hydrogel, Biomaterials. DOI: 10.1016/j.biomaterials.2013.09.065

add to favorites email to friend print save as pdf

Related Stories

Model recreates wear and tear of osteoarthritis

Jun 19, 2013

(Medical Xpress)—There's a reason osteoarthritis is often called wear-and-tear arthritis: Repeated stress on joints over time results in degeneration of the soft cartilage that normally distributes loads ...

Recommended for you

Researchers bring clean energy a step closer

11 hours ago

For nearly half a century, scientists have been trying to replace precious metal catalysts in fuel cells. Now, for the first time, researchers at Case Western Reserve University have shown that an inexpensive metal-free catalyst ...

The construction of ordered nanostructures from benzene

16 hours ago

A way to link benzene rings together in a highly ordered three-dimensional helical structure using a straightforward polymerization procedure has been discovered by researchers from RIKEN Center for Sustainable ...

Superatomic nickel core and unusual molecular reactivity

16 hours ago

A superatom is a combination of two or more atoms that form a stable structural fragment and possess unique physical and chemical properties. Systems, that contain superatoms, open a number of amazing possibilities ...

NETL invents improved oxygen carriers

Feb 24, 2015

One of the keys to the successful deployment of chemical looping technologies is the development of affordable, high performance oxygen carriers. One potential solution is the naturally-occurring iron oxide, ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.