Injectable Implant: goes in as a liquid, light locks it in place

For damaged faces, a smart new biomaterial provides a non-invasive way to reconstruct soft tissue. Injected as a fluid, massaged into place, and converted to a solid with LEDs.
Written by Janet Fang, Contributor on

Scientists have engineered light-activated tissue transplants. These can be injected in liquid form into your face, then molded and locked into place when exposed to a special light.

Right now, trauma or disease patients who need facial tissue reconstruction get acid-based injections like Juvederm or Restalyne, which provide temporary corrections. Synthetic materials can be a more permanent solution, but they might get rejected by the body and they can’t nicely mimic the soft tissues of the face.

This new biomaterial, developed by Johns Hopkins’s Jennifer Elisseeff and colleagues, is made of a naturally-occurring hyaluronic acid and an FDA-approved synthetic polymer called polyethylene glycol (PEG).

This is how it works (pictured):

  1. The liquid implants are injected under the skin.
  2. Once in the face, they’re massaged into the right shape for the injury.
  3. Then, green light-emitting diodes (LEDs) are shined on the skin, penetrating up to 4 mm deep and converting the liquid to a longer-lasting material. The solid hydrogel traps the acid particles, fixing the implant into place.

In rats, the implants maintained their original size and shape for over a year. (That’s at least twice as long as standard implants in rodent models.)

Currently, soft-tissue implants fall into two general categories. "You can either inject something and once it's in the body do nothing about it, or you can create an external implant which is then surgically implanted,” Elisseeff explains.

The latest implants offer a different approach, enabling doctors to tailor the implant to each patient's needs. "By tuning the properties for the material we can match the surrounding mechanical properties, whether you're in more of a fatty area, a muscle area or a skin area," she adds.

In 3 human patients scheduled for tummy tucks, the implants held their shape and height for 12 weeks after surgery. The implants did, however, cause more inflammation than expected.

Another issue is that the material degrades and could require reinjections every year or so – but the team thinks new tissue may actually grow into the implants in time. Cells can grow and heal the injury while supported by the implant, and after a while, the implant can be easily removed by injecting an enzyme that degrades it.

The results were published in Science Translational Medicine last week.

Images: Science/AAAS

This post was originally published on Smartplanet.com

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