Slime technology moves at a snail's pace

A gardener’s worst nightmare they might be, but that hasn’t stopped engineers from trying to get to the bottom of what makes snail slime so special.

Eat my butter, slow coach!

To their surprise, despite that fact that it can act as both glue and a lubricant, there was nothing inherently special about snail slime – in fact, hair gel and peanut butter could do the job just as well.

Christian Clasen of the Catholic University of Leuven (CUL), who worked on the study, said: “Who would have thought that snails could use other soft solids such as mayonnaise or axle grease as an adhesive lubricant to climb up vertical walls?”

The team, from the Massachusetts Institute of Technology (MIT) in the US, and CUL in Belgium, looked at how the cycle of glue breakdown and repair works in natural snail slime so that they could find the ideal slime substitute for their wall climbing robot.

Co-worker Randy Ewoldt, of MIT, said: “An important result is that snail mucus per se is not required for robots to climb walls. We can make our own adhesive locomotion material with commercial products instead of harvesting slime from a snail farm.”

After calculating the ideal slime properties that a climbing robot would need, the team found several ideal candidates, including hair gel and peanut butter. This came as some relief for Ewoldt as he was all too familiar with the pitfalls of harvesting snail slime.

He said: “I would entice a slug or snail with a piece of lettuce to crawl across a glass plate, and on the good days it would co-operate and leave enough of a slime trail for me to collect and test.”

The work is reported in the latest edition of the Royal Society of Chemistry journal Soft Matter.