Slimy slugs, it turned out, could have life-saving applications.Harvard University researchers developed the mucus secreted by slugs that not onlymoves with the body, it also sticks to wet surfaces. 

Scientists from the university's Wyss Institute for Biologically Inspired Engineering developed a bio-glue using the mucus secreted by the DuskyArion slug which it uses to defend itself against predators, BBC reported.The team, led by Dr.Jianyu Li, a 2010 Polymer Science and Engineering graduatefrom the Zhejiang University in China,  engineered the material to take on the key features of the slug mucus.

Trinity of attraction

The team developed and produced two components from the mucus.One was the actual adhesive and the second was a biochemical shockabsorber.Li explained the extreme stickiness of the medical glue to a combination of the attraction between the positively charged glue and negativelycharged cells in the body; the manner the glue penetrates physically the tissue surfaces; and the covalent bonds between atoms in the cell surface andthe glue.

According to Li, when they tested the bio-glue, they were able to close a hole in the heart of a pig.It is just one of the things the glue could do.Becausethe material is so tough, stretchable, and compliant, its possible applications are pretty broad, Li said.He foresees the medical glue used as a skinpatch or as a liquid that is injected into wounds that are deeper in the body. 

Li added that when they experimented with the glue, they found it was not toxic to living tissue and thrice stonger than any other medicaladhesive on the market.The glue solved a big challenge that the medical community grappled with over the years, but at the same time, it opened upmajor opportunities in a medical setting.The result of Harvard's experiment was published in the Science journal. 

During the experiment, when they stuck the glue to a surface, within three minutes, it adhered to the surface.After some more minutes, its adherenceeven became stronger, and after 30 minutes, the glue was as strong as the own cartilage of the body where it was stuck.Given these positive results, Lisaid they are thinking of using the glue to release drugs to a specific body part or organ, or to stickmedical gadgets to organs such as  devices to helpthe heart beat.

Animal experiments using a pig and mice

Science Daily reported that the Harvard researchers tested also the medical glue on several dry and wet pig tissues like the skin, cartilage, heart,artery, and liver.The bio-glue bound to all these pig parts with significantly greater strength compared to other medical adhesives.In the case of thepig's heart, after they sealed it with the medical glue, the scientists mechanically inflated and deflated the heart and had it undergo thousands of cyclesof stretching.

The Harvard team also tried it on lab rats and found that the bio-glue maintained its bonding and stability when they implanted it for two weeks.When the researchers applied the medical glue to a liver hemorrhage in mice, neither did it damage the tissue nor adhered to surrounding tissues, which was notthe case when super glue and a commercial thrombin-based adhesive were used.

Adam Celiz, a co-author of the study, sees wide-ranging applications for the bio-glue. "We can make these adhesives out of biodegradable materials, sothey can decompose once they've served their purpose.We could even combine this technology with soft robotics to make sticky robots, or withpharmaceuticals to make a new vehicle for drug delivery," said Celiz, a lecturer at the Department of Bioengineering of Imperial College London.

Experts who were not part of the study were impressed by the medical glue.Mark Grinstaff, the founder of Hyperbranch, a tissue adhesives companyand chemistry professor at Boston University, was impressed with the glue working on rat liver.Because of the slimy surface of the liver, it is hard toget materials to stick to his vital organ, Jeff Karp, founder of Gecko Biomedical, another adhesives firm, said. 

According to Li, the Harvard team did not use any of the molecules in the slug mucus.They mixed a sticky ingredient with something that can bestretched and withstand the stress that a moving body exerted.They used a hydrogel, or chemical soup made of water and a drizzle of a moleculefound in algae for the stretchable, shock-absorbing material, The Verge explained.

Although it is a very promising technology, Karp said the challenge is manufacturing it.He pointed out that manufacturing is a killer for many of thesetechnologies because to bring a product to the market requires large-scale production and ensuring it would not go bad when on the shelf waiting tobe used.