Zero-waste stretchable, soft robotic fingers that decompose in soil and act as fertiliser could be used in surgery.
The biodegradable and hyperdurable robotic fingers were designed by researchers at Seoul National University.
According to the United Nations Institute for Training and Research (UNITAR), global electronic waste (e-waste) reached around 62 million metric tonnes in 2022, with a large part not properly collected or recycled but instead landfilled or incinerated.
As soft robots are increasingly adopted across various sectors, including healthcare, end-of-life robotic systems are emerging as a new source of next-generation e-waste.
Soft robots and their associated electronic systems are usually made from multilayer thin-film structures composed of thermoset polymer elastomers, metal alloys, and extrinsic semiconductors.
These combinations make recycling almost impossible and prevent natural degradation, raising increasing concerns that such technologies are fundamentally unsustainable.
The body of the innovative robotic fingers is made from polyglycerol sebacate, a synthetic elastomer derived from glycerol and sebacic acid. Glycerol is a byproduct of biodiesel production, while sebacic acid is sourced from castor oil – both of which are plant-based.
Polyglycerol sebacate is a biodegradable polymer increasingly utilised in a range of biomedical applications.
Typical sensors and active components of electronic components are made of smartphones and circuit boards, which are currently filling landfill sites.
For the soft robotic fingers, the researchers used a class of electronics called transient inorganics, components engineered to dissolve under specific conditions.
The adhesive that bonds the electronic layer to the elastomer body is polyanhydride-based, a polymer class that breaks down when it comes into contact with water.
This new fully compostable robot survives over one million uses, then disappears in the soil.
The robot’s structural frame is constructed from PGS, a water-free biodegradable elastomer characterised by low hysteresis and strong elastic recovery.
There is growing awareness of the environmental impact of surgical robots.
Each robotic procedure generates an estimated 814 kg CO₂ equivalent in waste and emissions – comparable to a petrol-fuelled car travelling more than 3,200 kilometres. A major contributor is the high turnover of single-use instruments, which contradicts efforts toward sustainability in healthcare.
While robotic systems improve patient outcomes, their carbon footprint and resource consumption require urgent attention.
One of the problems with new technologies is leaving a residue in the environment, which can harm it including a usual surgical robot used once in a procedure, a sensor deployed in a field to monitor soil conditions, or even a device released into a body of water to measure pH.
Discarding them means these components end up in the landfill, especially if they are not properly recycled.
The SNU–Sogang–JKU joint research team was led by Professor Seung-Kyun Kang at Seoul National University, Professor Sang-Yup Kim at Sogang University, and Professor Martin Kaltenbrunner at Johannes Kepler University Linz.
The hope is that this fully biodegradable and compostable soft robotic electronic system, which maintains high performance and durability during operation yet completely returns to nature after use, will be adopted across all sectors.
