Biodegradable and biocompatible elastic materials for soft robotics, tissue engineering or stretchable electronics with good mechanical properties, tunability, modifiability, or healing properties drive technological advance, yet they are not durable under ambient conditions nor combine all attributes in a single platform. We have developed a versatile gelatin-based biogel, which is highly resilient with outstanding elastic characteristics yet degrades fully when disposed. It self-adheres, is rapidly healable and derived entirely from natural and food-safe constituents. We merge for the first time all favorable attributes in one material that is easy to reproduce, scalable and low-cost in production under ambient conditions. This biogel is a step towards durable, lifelike soft robotic and electronic systems that are sustainable and closely mimic their natural antetypes. Main: In 2025, an estimated 6 million tons of garbage will be generated per day 1 , with tech disposables being a rapidly growing contributor. End-of-lifetime appliances contain valuable materials that are laborious in recovery or toxic substances that are readily released into nature through landfilling or improper treatment 2. Biodegradable 3-6 and transient systems 7 are promising routes towards closing the loop on waste generation and create new opportunities for secure systems, but often at the cost of compromises in performance. Complex biological systems bridge this gap. They unite seemingly antagonistic properties-tough yet adaptive, durable and self-healing yet degradable-allowing them to perform a myriad of intricate tasks. Embodiments of technologies that intimately interface with humans naturally benefit from mimicking such soft, functional forms. A range of biomimetic systems 8 including soft machines 9 and electronic skins 10 achieve a high level of functionality by introducing self-healing 11,12 , intrinsic stretchability 13 , or the insightful merging of soft-to-hard materials 14. Waste flow issues and in vivo applications that avoid multiple surgeries are tackled with inextensible devices in the form of edible 3,15 and transient electronics 7,16. However, introducing stretchability to degradable devices remains challenging. Recent approaches focusing on stretchable biodegradable sensors 5 require expensive materials and are still wired to bulky measurement systems hindering implementation as wearable devices. Challenges here stem from the diverse material requirements,

End-of-lifetime appliances such as consumer electronics are typically trashed, as the various product designs and material compositions are difficult to recycle yet are cheaply produced. Additionally, the unsustainable use of rare and often toxic materials poses an environmental threat when released into nature due to improper treatment or landfilling. [2] Easy to recycle device designs, low-cost and renewable materials, and biodegradable or transient systems are promising approaches toward technologies with a closed life cycle and establish new opportunities across different fields from medicine and environmental monitoring to security and intelligence applications. [3] Current developments in robotics that focus on safe human-machine interaction, swarm robotics, and untethered autonomous operation are often inspired by nature's diversity. [4] The complexity we find in nature drives scientists from various fields to establish soft and lightweight forms of robots that aim to replicate or mimic the fluent motion of animals or their efficient energy management. [5,6] In future, the increased integration of such soft robots in our everyday life raises, in close analogy to consumer electronics, environmental concerns at the end of their life cycle. Again, we can learn here from nature and design our creations sustainably and mitigate the problems of currently used technology. In contrast to standardized industrial robots that are already integrated in recycling loops, bioinspired robotics will find various applications in diverse ecological niches. [7] Possible examples range from soft healthcare machines that support elderly people in their everyday lives to robots that first harvest produce and afterwards become compost for next season's plants. Current demonstrations with transient behavior include elastic pneumatic actuators, [8] wound patching millibots operating in vivo, [9] robot swarms for drug delivery, [10] or small grippers that are controlled by engineered muscle tissues. [11] These developments benefit from major research activities toward bioresorbable electronic devices, [12] which are mainly explored for the biomedical sector, and sustainable energy storage technology, [13] seeking to resolve environmental concerns for the increasing demand of energy for mobile appliances. Bringing those fields together will be the future challenge for autonomous robots, whether their development focuses on performance, sustainability, or both. The efficient integration of actuators, sensors, computation, and energy into a single robot will require new concepts and ecofriendly solutions, and can only be successful if material scientists, chemists, engineers, biologists, computer scientists, and roboticists alike join forces.The advancement of technology has a profound and far-reaching impact on the society, now penetrating all areas of life. From cradle to grave, one is supported by and depends on a wide range of electronic and robotic appliances, with an ever more intimate integration of the digital and biological sp...

Soft robotics greatly benefits from nature as a source of inspiration, introducing innate means of safe interaction between robotic appliances and living organisms. In contrast, the materials involved are often nonbiodegradable or stem from nonrenewable resources, contributing to an ever-growing environmental footprint. Furthermore, conventional manufacturing methods, such as mold casting, are not suitable for replicating or imitating the complexity of nature’s creations. Consequently, the inclusion of sustainability concepts alongside the development of new fabrication procedures is required. We report a customized 3D-printing process based on fused deposition modeling, printing a fully biodegradable gelatin-based hydrogel (biogel) ink into dimensionally stable, complex objects. This process enables fast and cost-effective prototyping of resilient, soft robotic applications from gels that stretch to six times their original length, as well as an accessible recycling procedure with zero waste. We present printed pneumatic actuators performing omnidirectional movement at fast response times (less than a second), featuring integrated 3D-printed stretchable waveguides, capable of both proprio- and exteroception. These soft devices are endowed with dynamic real-time control capable of automated search-and-wipe routines to detect and remove obstacles. They can be reprinted several times or disposed of hazard-free at the end of their lifetime, potentially unlocking a sustainable future for soft robotics.

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/advs.201903391. This publication is dedicated to Siegfried Bauer, who has sadly passed away during the course of this work 5th Anniversary Article [ †] Deceased December 2018.

Graphical abstractHighlights► Vacuum-evaporated polyethylene (PE) is a highly stable and trap-free dielectric. ► PE supports low-hysteresis transport in C60 and pentacene. ► PE additionally allows ambipolar transistor operation of 6,6′-dibromoindigo with balanced mobilities of ∼0.3 cm2/Vs. ► This work shows that high-quality gate dielectrics consisting of polymeric materials can be vacuum-processed.