Elsevier

Extreme Mechanics Letters

Volume 39, September 2020, 100784
Extreme Mechanics Letters

EML webinar overview: Extreme mechanics of soft materials for merging human–machine​ intelligence

https://doi.org/10.1016/j.eml.2020.100784Get rights and content

Abstract

Long-term, high-efficacy and highly compatible interfaces between human bodies and machines are critical to both addressing grand societal challenges such as healthcare and answering great scientific questions such as understanding human brain. We propose to understand and exploit soft materials technology – polymers, elastomers, hydrogels and biological tissues with designed properties – to form the interfaces between human bodies and machines. In this Extreme Mechanics Letters (EML) webinar (Zhao, 2020), we discussed the design of soft materials to achieve extreme mechanical properties, which are crucial to forming such long-term, high-efficacy and highly compatible interfaces that can potentially merge humans and machines and their intelligence ultimately. EML Webinar speakers and videos are updated at https://imechanica.org/node/24098.

Introduction

Whereas human tissues and organs are mostly soft, wet and bioactive; machines such as electronic devices and robots are commonly hard, dry and biologically inert. What if we can form long-term, high-efficacy and highly compatible interfaces between human bodies and machines to potentially merge humans and machines and their intelligence? Such interfaces can be crucial to both addressing grand societal challenges such as healthcare and answering great scientific questions such as understanding human brain.

For example, wearable electronics, medical equipment and implantable medical devices are medical machines that attempt to merge with human bodies over timescales ranging from hours, to days, to months and years. While these medical machines have been dramatically advanced over the last few decades, their interfaces with human bodies remain mostly the same, for example, metal electrodes on tissues. The primitive interfaces often severely hamper the medical machines’ effectiveness and duration in monitoring, diagnosis and therapy of healthy people and/or patients. While medical machines together with artificial intelligence hold great promise to revolutionize healthcare [4], [5]; long-term, high-efficacy and highly compatible interfaces between the machines and human bodies will indeed play a key role in this revolution. As another example, although more and more powerful computers are continually being developed, the interfaces between computers and human brains are still limited to merely a few thousand neurons among human brain’s approximately 86 billion neurons [6]. Simultaneous interrogation of millions of neurons over the long term such as months to years will potentially give a new understanding of human brain. However, such understanding will rely on the development of long-term, high-bandwidth and highly compatible brain–machine interfaces. Besides the abovementioned examples, the merging of humans and machines will potentially revolutionize other fields such as artificial intelligence, robotics and virtual reality, making similar levels of impacts on the society and science.

Despite the great promise, the merging of human bodies and machines is extremely challenging, largely because of the dramatically different properties between human bodies and machines. Existing machines mostly rely on engineering materials such as metals, silicon, glass, ceramics and plastics to communicate and interact with human bodies. On the other hand, the major compositions of human bodies are polymers and water, which usually constitute soft materials or hydrogels with moduli ranging from a few pascals to a few megapascals. The hard, dry and inorganic characteristics of engineering materials are intrinsically unmatched or incompatible with the soft, wet and living nature of biological tissues and organs.

Section snippets

Soft materials technology

We propose to understand and exploit soft materials technology – polymers, elastomers, hydrogels and biological tissues with designed properties – to form the interfaces between human bodies and machines (Fig. 1) [1], [7], [8]. On one hand, we design soft materials that possess mechanical and physiological properties similar to various tissues and organs of human bodies to form long-term and highly biocompatible interfaces with human bodies [9]. On the other hand, we integrate or embed machines

Extreme mechanics of soft materials

In developing the soft materials technology, we can leverage the great achievements in biology, materials and machines over the last few centuries. In particular, since the major compositions of the soft materials are polymers and water, the knowledge from polymer chemistry and physics is of foundational importance to soft materials technology [10], [11], [12], [13]. Furthermore, because the soft-material interfaces will act as part of human bodies and part of machines over the long term, we

Summary

This paper summarizes the topics discussed in an EML webinar given on May 6th 2020 [14]. While soft materials technology holds great promise to provide long-term, high-efficacy and highly compatible interfaces between human bodies and machines, we need to design, exploit and understand many more properties of the soft materials other than the ones discussed in this webinar to reach the full potential of such interfaces.

For example, hydrogels with high electrical conductivity and/or high

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

This work was supported by the National Science Foundation (EFMA-1935291) and the U.S. Army Research Office through the Institute for Soldier Nanotechnologies at Massachusetts Institute of Technology (W911NF-13-D-0001).

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