Imitating Mussels’ Adhesive Qualities for Medical Uses

If imitation is the sincerest form of flattery, then common marine mussels are getting a lot of love these days.

They can stick to most any surface, and in wet and turbulent conditions. Philip Messersmith, a professor of biomedical engineering at Northwestern adhesionUniversity’s McCormick School of Engineering and Applied Science, has created new materials that have applications in the medical field by mimicking the mussels’ adhesive proteins, reports Azonano.com.

“Mussel adhesion is a remarkable process involving secretion of liquid protein glue that hardens rapidly into a solid, water-resistant adhesive,” Messersmith says. “Several aspects of this process inspire our development of synthetic materials for practical applications. An unusually compelling opportunity for translation of mussel-adhesion concepts is in the repair or reconstruction of tissues in the human body, where water is ubiquitous and its presence represents a challenge for achieving desired outcomes.”

The key to the sticky glue that comes from the foot of the common mussel (Mytilus edulis) is found in a family of unique proteins that contain a high concentration of catecholic amino acid DOPA (dihydroxyphenylalanine). Messersmith’s biomedical materials all contain a synthetic form of DOPA.

Messersmith is not the only scientist who has based research on the adhesive qualities of mussels. German researchers have produced other medical applications based on the DOPA protein.

Messersmith has developed three medical applications based on the synthetic DOPA protein: fetal membrane repair, antibacterial hydrogels, and cancer-fighting polymers. He outlined these applications at a symposium in February at the annual meeting of the American Association for the Advancement of Science.

Fetal membrane repair. Fetal membranes sometimes occur spontaneously or after a surgical procedure. Because these membranes do not self-heal well, a membrane rupture can lead to early labor, premature birth, or other complications. Messersmith’s polymer adhesive acts as a liquid glue for wet tissue and deals with fetal membrane defects.

Self-setting antibacterial hydrogels. Silver’s antibiotic properties at low concentrations have created a stir of interest to incorporate them into medical devices. Messersmith has joined the effort. He uses silver both to induce hydrogel cross-linking through catechol oxidation and to create silver nanoparticles. Those nanoparticles then are embedded within the hydrogel structure, releasing silver ions to produce an antibacterial effect.

Cancer drug delivery. One of Messersmith’s polymers is pH-sensitive. It is stable and inactive in the bloodstream but becomes activated when it enters an acidic tumor environment, releasing the drug. Another design modifies the surface of gold nanorods because  of a mussel-inspired polymer coating that helps the nanorods target cancer cells. When they are near the target cells, near-infrared light irradiates the nanorods, heating them enough to destroy only the cancer cells.

Source: “Mussel-Inspired Polymer Coating Helps Gold Nanorods Target Cancer Cells,” Azonano.com, 2/18/13
Image by public domain.