Velcro is pretty handy stuff, but imagine if there was a soft, stretchy material with the same qualities. Well, now there is. Scientists from the University of California, San Diego have created a self-healing hydrogel that binds together in seconds, essentially copying the Velcro process at a molecular level. The new material could potentially find use in medical sutures, targeted drug delivery, industrial sealants and self-healing plastics.
The secret to the jello-like polymer hydrogel is its "dangling side chain" molecules, that reach out toward one another like long, spindly fingers. When developing the gel, a team led by bioengineer Shyni Varghese ran computer simulations, in order to determine the optimal length for these molecules. The resulting substance is capable of healing cuts made to itself - or of bonding with another piece of hydrogel - almost instantly.
The behavior of the material can be controlled by adjusting the pH of its environment. In lab tests, two pieces of the gel bonded together when placed in an acidic (low pH) solution. When the pH of that solution was raised, however, they easily separated. The process was repeated several times, without any loss in strength of the "weld" point when the pieces were joined.
Because of its strength in acidic environments, it could be ideal for sealing ulcers in the stomach, or for targeted drug delivery to ulcers. It could also be well-suited for patching holes on containers of acid - in fact, that use has already been demonstrated in the lab.
Varghese is now hoping to create other versions of the hydrogel that self-heal at different pH levels, thus allowing it to be used outside of acidic conditions. A paper on her research was published this week in the journal Proceedings of the National Academy of Sciences.
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