Ultra-elastic patches for wounds: load cells and testing stretchy stuff

Published On: July 10 2024

Please be advised that this article includes details of medical procedures and testing. So if you’re squeamish, you might prefer to browse our load cell shop instead!

Modern surgery may be less invasive than for previous generations, but there is still a need to close wounds securely. According to a paper in Nature Communications, there are promising developments in bioadhesive materials that can replace traditional closure methods.


Stitches, staples and stretchy sticky patches

Traditional closure techniques involving stitches (sutures) and staples can contribute to wound inflammation, post-operative pain and the formation of scar tissue.

The team from the University of North Carolina developed a patch material that sticks instantly to tissues and can stretch to more than 300% of its length without losing its elasticity. Their line of auxetic, elastic, and sticky (AuxES) patches also adhere to wet tissues, including organs, unlike bioadhesives that become ineffective in wet environments.

What’s more, by coating them in“extracellular vesicles”, AuxES patches can:

“Demonstrate robust wound healing capability in vivo without inducing a foreign body response and without the need for patch removal that can cause pain and bleeding.”


Testing the patches: tensile strength

So, how do you actually test the tensile strength of the patches, and its adhesion to wet organic tissue?

“The tensile properties of the patches were determined using … a linear stage actuator as the stretching mechanism, and a 5 kg load cell and amplifier as the stationary anchor … The ends of the patch were clamped between the linear actuator and the load cell, and the patches stretched 0.125mm/s. The load cell … provided the stress vs. strain curve to determine the mechanical properties.”

Having established the tensile strength, the team now needed to check the bioadhesion to ex vivo tissues, in this case mouse livers.

“The mouse livers were (placed)… over the stationary load cell of the tensile testing apparatus. Next, patches were placed on the mouse liver … such that one end of the patches hung over the edge of the liver by 5mm, which was attached to the linear translation stage of the tensile testing apparatus. The patches were stretched at 0.125mm/s, and the highest force generated during the stretching procedure was noted as the detachment force.”


Materials testing with load cells

Our load cells are very popular for use in materials testing jigs and apparatus. We regularly supply load cells for OEM materials testing machines.

And of course we’ve written articles about load cells and materials testing too, including:

and appropriately for Wimbledon week:


Materials testing with our load cells

If you need to test your materials to their limits, contact us to discuss your load cell requirements today..