Mussel-inspired glue may make foetal surgery safer

Scientists have developed a strong glue based on a mussel adhesive which could make performing surgery on foetuses safer in the future.

Whether to perform surgery on a foetus is a heart- wrenching decision. It involves penetrating the highly delicate amniotic sac, increasing health risks to the foetus.

Now, researchers have created a glue, inspired by the tenacious grip of mussels on slippery rocks, that could one day help save the lives of the youngest patients.

"One of the biggest risks in performing surgery on foetuses is not the surgical procedure itself, but the insertion of a foetal scope through the amniotic sac, which is very fragile," said Diederik Balkenende, a postdoctoral researcher at the University of California, Berkeley in the US.

"After the surgery, the small hole where the scope penetrates the membrane can start to tear. If it tears completely, premature labour is likely," said Balkenende.

Since these operations are often done in the second trimester well before the foetus is fully developed, early delivery increases the risk of foetal morbidity.

An adhesive that can prevent the amniotic sac from tearing could help the foetus remain in the womb longer, which would potentially lead to a healthier future for the baby, researchers said.

A well-known example of a severe birth defect that would make a foetus a candidate for surgery is spina bifida, a condition in which the neural tube - the part that becomes the baby's brain and spinal cord - does not develop or close properly. To fix such problems a few decades ago, surgeons had to cut open a woman's abdomen and womb.

Now, doctors can use skinny endoscopic tools to perform operations through a small hole. Still, to reach the foetus, the instruments must penetrate the amniotic sac, which cannot heal or easily be sewn shut because it is so fragile. Sealing it with an adhesive is a challenge because the membrane is wet. Delivering a surgical glue post-operation is a major hurdle.

Mussels produce sticky substances that allow them to cling to rocks and ship hulls in wet environments, even under pounding waves.

Developing mimics of these substances for surgical use involves turning them into hydrogels. However, this conversion so far has required chemical cross-linkers that could be toxic to foetuses.

Balkenende, wanted to eliminate the cross-linkers. He infused an adhesive ingredient from the mussel foot called dihydroxyphenylalanine, or DOPA, into a special polymer that can dissolve in a biocompatible solvent.

The solution can then be drawn into a syringe. To test their material, the researchers used pieces of a membrane that surrounds a cow's heart as a model of the amniotic sac.

They applied the solution with the syringe to overlapping pieces of the wet, filmy tissues. On contact with moisture on the tissues, the mixture immediately became rubbery. After about an hour, the glue set and held the pieces together.

However, even with the right polymer and solvent, the researchers still needed to figure out how the solution might work in a real surgery.