University engineers use dead spiders as mechanical grippers

Most people would see a dead spider and throw the insect away. Two Rice University engineers had other ideas. University of Houston engineers recently unveiled a study describing how they took dead spiders and turned them into mechanical grippers capable of grasping different types of objects, even objects that weighed more than the dead insect. The idea came to them after thinking about how spiders move their limbs. Unlike humans and other mammals, which use their nervous system to send signals to their muscles to contract, spiders use hydraulics. Essentially, spiders have a chamber near their head that sends blood through their body and into their limbs, forcing them to expand. When blood pressure is relieved, the legs contract. “We were moving things around the lab and noticed a spider curled up at the edge of the hallway,” said lead author Faye Yap, recounting the moment that spurred the possible study. “We were really curious about why spiders curl up after they die.” After a quick internet search, they found their answer. But that only sparked more curiosity. “At the time, we were like, ‘Oh, that’s super interesting.’ We wanted to find a way to take advantage of this mechanism,” she added. After delving into the anatomy of the arachnid, they realized that the spider’s hydraulic chamber, or parasoma, actually had separate internal valves that allow the insect to move each leg individually. “The dead spider doesn’t control these valves,” said Daniel Preston, a Rice engineering professor who was involved in the study. “They are all open. This worked in our favor in this study, as it allowed us to control all of the legs at the same time.” By using wolf spider cadavers, the engineers also realized they could replace blood flow with a puff of air, causing the same hydraulic response in the spiders’ legs. Setting up the spider contraption was quite simple, Yap said. They inserted a needle into the chamber of the parasoma, keeping it stable with a dab of super glue. Then, at the other end of the needle, one of the lab’s test rigs or a hand-held syringe delivered a tiny amount of air to activate the legs almost instantly.” He begins to experience some wear and tear as we approach 1,000 cycles,” Preston said. “We think it’s related to issues with joint dehydration. We think we can overcome that by applying polymer coatings. ‘So what’s the point of all that stuff around at these small scales, and maybe even things like microelectronics assembly,’ Preston said. Yap, who coined the process of turning spiders into mechanical pincers as ‘necrobotics’, added: “Another application could be to deploy it to capture smaller insects in the wild, as it is inherently camouflaged. “Additionally, Preston touted the durability of necrobotics, the spiders themselves are biodegradable,” Preston said. “So we’re not introducing a big waste stream, which can be a problem with more traditional components.” by something that looks straight out of a sci-fi book, but they want to reassure everyone that what they’re doing doesn’t count as resuscitation. inanimate, and we’re using it in this case strictly as material derived from a once-living spider,” Preston said. “It provides us with something really useful.” Graduate students Zhen Liu and Trevor Shimokusu and postdoctoral fellow An oop Rajappan also co-authored the study.

Most people would see a dead spider and throw the insect away. A few engineers at Rice University had other ideas.

University of Houston engineers recently unveiled a study describing how they took dead spiders and turned them into mechanical grippers capable of grasping different types of objects, even objects that weighed more than the dead insect.

The idea came to them after thinking about how spiders move their limbs. Unlike humans and other mammals, which use their nervous system to send signals to their muscles to contract, spiders use hydraulics.

Essentially, spiders have a chamber near their head that sends blood spurting through their body and into their limbs, forcing them to expand. When blood pressure is relieved, the legs contract.

“We were moving things around the lab and noticed a spider curled up at the edge of the hallway,” said lead author Faye Yap, recounting the moment that spurred the eventual study. “We were really curious about why spiders curl up after they die.”

After a quick internet search, they found their answer. But that only aroused more curiosity.

“At the time, we thought, ‘Oh, that’s super interesting.’ We wanted to find a way to take advantage of this mechanism,” she added.

After digging deeper into the anatomy of the arachnid, they realized that the spider’s hydraulic chamber, or parasoma, actually had separate internal valves that allowed the insect to move each leg individually.

“The dead spider doesn’t control these valves,” said Daniel Preston, a Rice engineering professor who was involved in the study. “They are all open. This worked in our favor in this study, as it allowed us to control all the legs at the same time.”

Brandon Martin

Daniel Preston and Faye Yap.

By using wolf spider corpses, engineers also realized they could replace blood flow with a puff of air, causing the same hydraulic response in the spiders’ legs.

Setting up the spider contraption was pretty straightforward, Yap said. They inserted a needle into the chamber of the parasoma, holding it steady with a bit of super glue. Then, at the other end of the needle, one of the lab test rigs or a hand-held syringe delivered a minute amount of air to activate the legs almost instantly.

“It starts to get some wear and tear as we approach 1,000 cycles,” Preston said. “We think it’s linked to joint dehydration issues. We believe we can overcome this by applying polymer coatings.

So what’s the point of all this?

“There are a lot of pick and place tasks that we could look at, repetitive tasks like sorting or moving objects at these small scales, and maybe even things like microelectronics assembly,” Preston said.

Yap, who coined the process of turning spiders into mechanical pincers as ‘necrobotics’, added: ‘Another application might be to deploy it to capture smaller insects in the wild, as it is inherently camouflaged’ .

Additionally, Preston touted the durable necrobotics.

“Plus, the spiders themselves are biodegradable,” Preston said. “So we’re not introducing a big waste stream, which can be a problem with more traditional components.”

Preston and Yap said they understand some people might be discouraged or scared by something that looks straight out of a sci-fi book, but they want to reassure everyone that what they’re doing does not count as a revive.

“Although it looks like it may have come back to life, we are certain it is inanimate, and we are using it in this case strictly as material derived from a once-living spider,” Preston said. “It provides us with something really useful.”

Graduate students Zhen Liu and Trevor Shimokusu and postdoctoral fellow Anoop Rajappan also co-authored the study.

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