Morphing Polymer Technology: Bone-Growth Inspired Material Revealed

Stiffness, defining how tough material is under certain forces, is an important quality in most materials including polymers. As most engineers dream of a material that can morph into any shape, be soft or stiff when it is required; this development may reveal a way to achieve that dream. Recently, researchers from Linköping University in Sweden and Okayama University in Japan have developed an electroactive polymer, a “biohybrid variable-stiffness soft actuator” in their terms, that can stay like a gel until a low voltage is applied. Their findings were later published with the title “Biohybrid Variable-Stiffness Soft Actuators that Self-Create Bone“.

How does the new polymer work?

As the researchers claim, it is very much like an electrically stimulated micro-robot. It can change shapes, or toughen at the desired time. According to the research, the material uses an electroactive polymer that can be stimulated by electricity inside an “alginate hydrogels functionalized with cell-derived plasma membrane nanofragments (PMNFs) as the bioinducing source for mineralization and stiffening of the gel layer”. These membrane fragments are from special cells that take part in our bone development. The final material stays like a gel, bends into shape in hard-to-adapt environments, and then hardens to support the structure.

The main gimmick of the technology is to replicate the process of bone hardening. It is like how a baby’s skull is soft tissue while being born, mineralizing and hardening after years. As there are still issues with controlling the thickness and some qualities of the materials, it is very promising research especially when looking at the possible medical applications and can save lives when it is completed.

Credit: Pexels

Possible use cases

With developments around material quality and strength, it may be used in surgical operations on bones that are fragmented, to go in between and fit as perfect support. Especially with robotic surgeries, it might be like a 3D printer material for complex operations on the human body if it is developed to its perfected state. In the end, robotic surgeries are far more advanced than ever if you remember my previous article “A Robot Performs First Surgery on Soft Tissue Without Human Help“.  Other than that, the researchers also state:

PMNF-based biohybrid materials could be used in new tools for tissue engineering, including robot-assisted surgical interventions, such as morphing bioadhesives, to adhere (electronic) components to bone, or to create a hard protective shell around such electronic components that integrates into the body.

Meaning that the technology can also be used as a natural protection for electronic or foreign components inside the body. A bioadhesive that can create protective shells in between tissues would be a really interesting concept as well. The research surely has a lot of potential in terms of bioengineering.

References: Cao, D., Martinez, J. G., Hara, E. S., Jager, E. W. H., Biohybrid Variable-Stiffness Soft Actuators that Self-Create Bone. Adv. Mater. 2022, 2107345. https://doi.org/10.1002/adma.202107345