Scientists are looking for stickier substances.
Watch out Elmer’s, there are some new glue upstarts approaching. Drawing from bacteria, beetles, slugs and worms, scientists are experimenting with all kinds of novel adhesives in the lab. Some materials are strong enough to hold a grown man while others could replace bandages and stitches. Here’s a look at these sticky substances.
Streptococcus pyogenes bacteria was used to create a molecule-binding glue.
Biochemists Mark Howarth and Bijan Zakeri from Oxford University developed a superglue last year that works on a very, very small scale. They created their molecule-binding glue by engineering Streptococcus pyogenes, bacteria that can cause problems for humans ranging from sore throats to flesh-eating disease. The bacteria contain a protein that hooks into human cells and invades them.
In the lab, the scientists’ molecular bond held protein fragments together without requiring UV light or catalysts. It also held strong in various temperatures and even in detergent. Since the molecular superglue won’t stick to anything else, the biochemists think this could have a range of applications ranging from aiding artificial photosynthesis to better cancer detection.
Asparagus beetles use a sticky subtance to attach their eggs to plants.
Asparagus beetles or Crioceris asparagi, have the ability to stick their eggs on the plant’s waxy surface so effectively that it requires a force 8,650 times higher than the egg’s weight to remove them.
Several years ago scientists Dagmar Voigt and Stanislav Gorb in Germany did an extensive study of the way the beetles attach the eggs and found that these insects evolved a way to get through the plant’s natural defenses. It secretes a composite the scientists said is made of solidified glue and wax crystals. Although the discovery could inspire new natural adhesives, Voigt and Gorb suggested their results might lead instead to beetle-resistant plants or new products that can cut through the glue and wash the eggs off.
Sandcastle worms keep their sand-based honeycomb structures glued together with an adhesive protein.
Intertidal dwelling sandcastle worms or Phragmatopoma californica live up to their name by constructing tubular homes in the California surf from sand, shell bits and its own natural protein adhesive.
University of Utah bioengineering professor Russell Stewart has long studied how these marine worms glue materials together underwater. Stewart wants humans to have similar abilities, particularly around mending broken bones. Over the past several years, he and his team have been experimenting with surgical cements that work somewhat like the sandcastle worm adhesive, staying liquid at room temperature and then solidifying at body temperature. They’ve been testing the medical glue on animal bones and tissues in the lab.
Gecko feet can cling powerfully to surfaces because they contain fine, hair-like structures called setae.
University of Kiel zoology professor Stanislav Gorb specializes in functional morphology and biomechanics. He’s probably best known for research that led to tape patterned after lizard feet. Gecko feet can cling powerfully to surfaces because they contain fine hair-like structures called setae. These setae are flexible, allowing geckos and some insects to walk on ceilings and glass. Gorb’s research group found a way to mimic that effect artificially.
The resulting silicone material was commercialized by the German fastening systems company Gottlieb Binder as Gecko Tape, which works underwater and leaves no residue after repeated uses. It’s also powerful enough that an 8-inch square can support a grown man dangling from it.
Insect larvae spin silky ribbons underwater to ensnare food or form protective casings.
When University of Utah bioengineering professor Russell Stewart isn’t studying sandcastle worms, he’s got his eye on caddisflies. Also known as rock rollers, these are insects whose larvae can spin silky ribbons underwater to ensnare food or form protective casings.
In 2010, Stewart and his colleagues discovered why the fly silk remains sticky underwater. By analyzing silk that caddisflies spun in the lab, the scientists found it contained proteins called fibroin and an amino acid known as serine. Similar to dental adhesives, the serine in caddisfly silk also has phosphates to help with binding. Although the individual silk threads are not particularly strong, an artificial version using many threads could serve as wet bandages that keep human tissues together. Researchers are still working on the material.
Adhesive gel inspired by slug secretions could keep skin together after surgery.
Recently Ithaca College biology professor Andrew Smith began talking about the end of surgical suture and staples. He envisioned a time when doctors use adhesive gel inspired by slug secretions to keep skin together post-surgery. Smith and several graduate students looked to slugs because they secrete gels that help them move along a variety of surfaces, including wet ones. The scientists carefully gathered samples from live slugs and found the substance contains polymers held together by metal ions that help the gel stiffen. They plan to continue studying the substance in hopes of creating an artificial version strong enough for humans.
Mussels are able to stick to wet rocks even when seas grow rough.
Mussels can stick to rocks and ship hulls despite crashing waves by producing a powerful adhesive protein. Penn State University associate professor of bioengineering Jian Yang and University of Texas-Arlington researchers studied mollusk proteins closely. Then they developed an injectable citrate-based mussel-inspired bioadhesive or iCMBA for short.
In the lab, their bioadhesive worked effectively on live rats. Unlike fibrin glue that’s currently used clinically, this new adhesive closed wounds. It also stopped bleeding instantly and accelerated healing. Many other scientists are also looking to mussel proteins for medical uses. Earlier this year Northwestern University biomedical engineering professor Phillip Messersmith created a material mimicking mussel glue that could be used to repair fetal tissue.