Researchers at Northwestern University (Evanston, IL, USA) and University Hospital Zurich (Switzerland) developed the mussel-mimetic tissue sealant, essentially a simple synthetic polymer containing dihydroxyphenylalanine (DOPA) and a catalyst that when combined form a sealant gel in 10 to 20 seconds. To test the material, the researchers punched holes three millimeters wide into human fetal tissue (in vitro) to replicate the tiny holes found in fetal membrane defects.

The researchers then applied a fibrin glue and three types of in situ forming poly(ethylene glycol) (PEG) based polymer hydrogels, and tested them for acute toxicity on direct contact with fetal membranes for 24 hours; for the determination of elution toxicity, extracts of sealants were incubated on amnion cell cultures for 72 hours. Both bonding and toxicity were assessed through morphologic and biochemical analysis, demonstrating that the mussel-inspired sealant had the best results in both categories. The study was published in the January 2010 issue of the American Journal of Obstetrics & Gynecology.

"We tested our mussel-inspired sealant on living fetal tissue and found it was both biocompatible and effective at sealing the tiny holes -- two features essential in such a material,” said coauthor Phillip Messersmith, Ph.D., a professor of biomedical engineering at Northwestern.

The fetal membrane is the structure that surrounds the developing fetus; defects in the membrane result either from incisions during endoscopic fetal surgeries used in the treatment of some birth defects, or premature and spontaneous ruptures in the fetal sac. These ruptures can lead to the leakage of amniotic fluid, resulting in premature labor or termination of the pregnancy.

The foot of the common mussel (Mytilus edulis) produces adhesive glue that keeps the shelled organism anchored to rocks and other objects, allowing them to withstand the extreme pounding of waves. Chemical analysis of this natural, waterproof glue have shown that the key to its adhesiveness is a family of unique proteins called mussel adhesive proteins, which contain a high concentration of DOPA.

Related Links:
Northwestern University
University Hospital Zurich