Injectable hydrogel uses “molecular Velcro” structure to resist body heat

Stanford scientists have developed a new hydrogel with a Velcro-like molecular structure that allows it to stay intact for longer at body temperature. The hope is that it could be injected into a patient and deliver drugs over weeks or months as it slowly dissolves.

Hydrogels are no stranger to the human body – researchers have been experimenting with them in medicine for years. They’ve shown promise as “smart” wound dressings, scaffolds to help damaged tissue regrow, and drug delivery systems that target particular areas like tumors, releasing their payload slowly over time or from triggers like mechanical force.

But one hurdle that hydrogels have to contend with is body temperature – the elevated heat can dissolve the gel too fast. So for the new study, the Stanford researchers set out to develop a hardy new hydrogel that wouldn’t come unstuck so easily.

The recipe called for two solid ingredients: long, thin polymer strands that are designed to tangle together, and nanoparticles that guide that tangling behavior. When the two are mixed together in water, the polymers wrap tightly around the particles, in a process the team likens to “molecular Velcro.”

But there are more in-depth physics going on in that process than you might realize. The team says that the bond between polymer and particle is strong enough to squeeze out the water molecules trapped between them. That allows the gel to congeal at room temperature, and hold its structure at the warmer temperature of the human body for longer.

The gel isn’t ready for human use in its current form, the team cautions – the particles are made from polystyrene, which you wouldn’t want in your body. But the next steps in the work are to swap them out for biocompatible materials.

“We are trying to make a gel that you could inject with a pin, and then you’d have a little blob that would dissolve away very slowly for three to six months to provide continuous therapy,” says Eric Appel, lead author of the study. “This would be a game-changer for fighting critical diseases around the world.”

The research was published in the journal Nature Communications.

Source: Stanford University

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