‘Elastic hydrogel’ shows promise in wound repair

16 Jul

Bioengineers have developed a strong hydrogel made of proteins that becomes as elastic as

skin and blood vessels when exposed to light.

hydrogel diagrams
When exposed to light, the protein-based gel mimics many of the features of elastic tissue such as skin and blood vessels.
Image credit: Nasim Annabi/BWH

Bioengineers have developed a new protein-based gel that,
when exposed to light, mimics many of the properties of
elastic tissue, such as skin and blood vessels.

While it is still early days – more tests need to be done before it is ready for human trials –

they hope the new biomaterial will one day be used in wound healing, such as after injury or


In the journal Advanced Functional Materials, the team – including members from Brigham

and Women’s Hospital (BWH) at Harvard Medical School in Boston, MA – describes the new material, its

key properties, and how they tested it in lab tissue and animal models of wound healing.

Co-senior author Nasim Annabi, previously an instructor at BWH, and now a an assistant chemical

engineering professor at Northeastern University, Boston, says:

“We are very interested in engineering strong, elastic materials from proteins because so many of

the tissues within the human body are elastic.”

One of the challenges bioengineers face in developing such materials is fine-tuning the

elasticity and flexibility to match that of body tissue.

“Our hydrogel is very flexible, made from a biocompatible polypeptide and can be

activated using light,” notes Prof. Annabi.

Bioengineered hydrogels are manmade jelly-like materials used in medicine to mimic the properties

of human tissue. But the ones currently in use have drawbacks, as co-senior author and professor Ali

Khademhosseini, who heads a tissue engineering lab at BWH, explains:

“Some synthetic gels degrade into toxic chemicals over time, and some natural gels are not strong

enough to withstand the flow of arterial blood through them.”

Hydrogel appears strong, elastic and degrades without toxic side effects

The researchers say their new biomaterial – called

photocrosslinkable elastin-like polypeptide-based (ELP) hydrogel – offers numerous benefits.

The ELP hydrogel is formed when a polypeptide – a chain of amino acids – is exposed to light.

Light causes strong bonds to form between the molecules along the chain, making it mechanically

stable without having to add chemicals.

When they tested the ELP hydrogel, the researchers found they could control not only its

toughness, but how much it swelled, and that it could withstand more stretching than artery tissue.

The authors also note that the hydrogel can be digested by naturally-occurring enzymes, and tests

on living cells did not reveal any toxic side-effects.

Turning to how the gel might be used, Prof. Annabi says they can see several possible

applications, such as using it a scaffold to grow cells, or incorporating it with cells in a dish and

then injecting them to get tissue to regrow. Another possible use is as a sealant to create a

protective barrier over a wound.

‘Great potential’ for clinical use

In further tests, the team found they could improve the wound healing power of the gel by

combining it with silica nanoparticles that had already been shown to stop bleeding. Prof. Annabi

says such an application would allow doctors to immediately stop bleeding with a single treatment.

She concludes:

“We see great potential for use in the clinic. Our method is simple, the material is

biocompatible, and we hope to see it solve clinical problems in the future.”

Grants from the National Institutes of Health and the National Science Foundation helped to fund

the study.

In March 2015, Medical News Today learned about another study that showed how wounds heal faster with help from nanoparticles.

In the Journal of Investigative Dermatology, a team from the Albert Einstein College of

Medicine of Yeshiva University describes how a test in mice showed – when compared with no treatment

– the experimental nanoparticle therapy helped skin wounds heal twice as fast.

Written by Catharine Paddock PhD

Copyright: Medical News Today