The growing applications of 'necrobotics': turning dead spider carcasses into biohybrid robots

In 2022, scientists at Rice University in the United States used the term "necrobot" to refer to the creation of biological robots from the dead bodies of animals. A study published in Advanced Science described how lead author Faye Yap and Daniel Preston of Rice's George R. Brown School of Engineering harnessed the unique physiology of wolf spiders to use them as mechanical grasping tools. They were able to grasp objects up to 130% heavier than their own weight and perform more than 1,000 gripping cycles, while maintaining precision and stability in the process. "It turns out that the spider, after it dies, is the perfect architecture for small-scale, naturally derived grippers," Preston said in a statement.

This was a first step toward automation and a new area of ​​research they called "necrobotics." Since then, their applications have been studied, especially for performing small, precise tasks such as manipulating electronic components like microchips. There's also talk of their use in superficial surgeries or when there's a shortage of medical equipment , and their natural camouflage makes them ideal for harvesting in the wild. At the same time, we're talking about low-cost, biodegradable robotics.

" Harnessing properties and mechanisms similar to those generated by nature can enable engineered systems with entirely new capabilities or advantages; this field of research is known as bio-inspired or biomimetic design ," they describe in the article.

"By observing organisms that have refined themselves through millennia of evolution, scientists and engineers have developed capabilities ranging from surface wettability modifications based on lotus leaves and Namibian beetles to adhesion mechanisms that emulate the toes of geckos," notes the Rice University research. It adds that researchers have also drawn inspiration from the locomotion of terrestrial animals and aquatic creatures to guide robot design.

To achieve something like this, the first step was to understand how their locomotion worked. Faye Yap herself admitted to the media that, as a mechanical engineer, she never imagined her research into hydraulics would end up being used in this way. It all began when she found a dead spider on the floor of her laboratory. After observing it, she realized that they always shrink when they die.

"Because spider legs only contain flexor muscles, after death, the spider's legs curl inward toward the body due to the lack of hydrostatic pressure ," the experts note. And Preston went on to explain that spiders "extend their legs thanks to a chamber (prosoma) near their heads that contracts and sends blood to their limbs, forcing them to unfold ." When the fluid volume decreases, the legs retract.

Yap took advantage of this natural hydraulic system in these arachnids' legs and inserted a needle into their prosoma. He secured the syringe with glue to form an airtight seal. This mechanism allowed him to move his legs as if the spider were alive, turning it into a biological robotic gripper. A process that only took about 10 minutes.

Going beyond inspiration, "biohybrid systems combine natural or engineered cells and tissues with artificial or inanimate components to generate biocompatible robots and actuators on a small scale," the published document describes. What seemed like science fiction may be a reality that has opened up new avenues of study.

In fact, 'La Voz de Galicia' reported in 2024 that Spaniard Raúl Villamarín Rodríguez, a cognitive technologist and vice president of Woxsen University in Hyderabad , is leading a project that envisions the use of robotic spider decay in surgeries. He presented this technology at the Cannes World Artificial Intelligence Festival. Furthermore, artificial intelligence can discover new uses for these biotic materials. The technology is still in its early stages of development, but its potential is promising.