The last few decades have witnessed unprecedented convergence between humans and machines that closely operate around the human body. Despite these advances, traditional machines made of hard, dry and abiotic materials are substantially dissimilar to soft, wet and living biological tissues. This dissimilarity results in severe limitations for long-term, reliable and highly efficient interfacing between humans and machines. To bridge this gap, hydrogels have emerged as an ideal material candidate for interfacing between humans and machines owing to their mechanical and chemical similarities to biological tissues and the versatility and flexibility in designing their properties. In this Review, we provide a comprehensive summary of functional modes, design principles, and current and future applications for hydrogel interfaces towards merging humans and machines.
Overview:
The main challenges of human–machine interfaces stem from materials. Existing machines largely employ conventional materials, such as metals, silicon, glass, ceramics and plastics, to communicate and interact with human bodies. However, the hard, dry and abiotic nature of these conventional materials is intrinsically contradictory with the soft, wet and living nature of biological tissues. In recent decades, intensive efforts have been devoted to transforming these conventional materials into flexible and stretchable structures to conformally interface with soft and curvilinear biological tissues. However, these structural designs do not alter the materials’ intrinsic properties, which may still hamper their communication and interactions with biological tissues. For example, the integration of conventional materials with tissues usually relies on physical attachment or surgical suturing, methods that face challenges such as non-conformal contact, unstable adhesion, tissue damage and/or scar formation. As another example, the properties of metallic electrodes, such as their high rigidity, low interfacial capacitance and low charge injection capacity, make them far from ideal for the electrical recording and stimulation of soft neural tissues. In addition, biological tissues often recognize these materials, even when in flexible and stretchable structures, as foreign bodies due to their inherently disparate properties, resulting in an adverse foreign-body response, biofouling, and fibrotic encapsulation or fibrosis. Such foreign-body response and subsequent fibrotic isolation from the surrounding tissues can severely compromise the long-term reliability and efficacy of the communication and interactions between humans and machines.
Because of their unique similarities to biological tissues and the versatility and flexibility in tailoring their properties, hydrogels have naturally emerged as a promising material candidate to act as an alternative or adjunct to conventional materials for bridging humans and machines.
After surgery I used hydrogel wound gel and hydrocolloid bandages. The wound healed really fast and the scar was minimal. I'm a believer in the wet-environment promotes healing by cell mobility argument. Silicone tape is pretty great too.
I was a competitive swimmer in high school. We had practice twice a day, and would always get pissed whenever we got a paper cut.
Because we never let the cut fully dry out and have a scab form, small cuts would take MONTHS to heal, and often result in scars when they shouldn't have.
Because of that I always assumed, dry conditions were ideal for healing.
A very specific type of wetness promoted by a bandage, might promote wound healing better than dry. I don't think high-school pool water will help.
New tissue growth is like the rest of our biology. Proteins are made in water solution inside cells. That has to get to the new tissue. Providing a scaffolding with a warm, wet, nutrient-rich environment around the wound should in theory make it heal faster and with less scarring, too. But these environments are also good for pathogen growth and invite infection. And removing detritus and pus and nutrient/gas exchange become issues as well. So just how moist and packed to keep a wound, and with what kind of packing and moisture, has been debated back and forth basically forever.
You're both right! Cell mobility is enhanced in wet / moist environments, as are the ion gradients that help guide cells to wounds. So during the initial phase of healing keeping the wound moist promotes healing, however it will never "close up" except in dry conditions. The promotion of the formation of scar tissue and other outer layers of skin is triggered by air + dry conditions. (When you get skin cancer you learn all sorts of fun things, wear your sunscreen kids.)
Sure, if you pour chlorine all over your wet wounds you'd probably have to let it dry before having a chance at healing. I'd advise against taking a gaping wound into the pool tho
Applying a hydrocolloid bandage immediately gives you a waterproof seal over the wound, so it basically lets you skip the “dry out and form a scab” part and go straight to the “sealed wound starts healing” part. The “wet” part is really just referring to how the wound is still “wet” underneath the scab.
I see hydrocolloid bandages in pharmacies/groceries a lot nowadays, so hopefully they’re helping modern swimmers avoid the pain you went through!
This is useful if you care about conformation and scare tissue. For everything else, micromachined electrodes/meshes are the superior alternative IMHO.
1. Neither Synchron nor Neuralink have adopted anything resembling this in their R&D stack (despite the hype and wild claims being around for 15-20 years).
2. Instability is a major concern. And the target application (surgical/augmentation) wouldn't compromise stability for...conformation. Impedance data on such devices are very much humidity-level dependent.
3. Soft matter degrades. Especially if it gets heated by nearby electronics or when subjected to HF signals (brains/synapses are >1kHz). As it does, its properties change.
4. Ionic diffusion will mess with your interface in vivo. It's just the way nature works.
Nature created a journal dedicated to reviews in materials science this year. That was the news for me.
the title is slightly misleading. it suggests content focused on the neuralink, brain-computer interface whereas the article is more of a general overview of all applications, including ephemeral ones like epidermal and wearable applications and ingestible diagnostics.
ephemeral ones seem more promising, especially in the near future.
could you also elaborate on the benefits of micromachined electrodes/meshes?
> Neither Synchron nor Neuralink have adopted anything resembling this in their R&D stack
The current state of a fast changing R&D group shouldn't be used to predict future state, especially when there's nothing close to a final product. They specifically talk about the problem of scar tissue, how biological films may be required, and how research is ongoing, here: https://youtu.be/YreDYmXTYi4?t=7009
As a side note I want to say that a seamless machine-human interface opens the downward arc of evolution where life serves matter. This will begin as a innocent attempt to "help" amazon warehouse workers become more efficient with an interface that lets them control a box pickup machine. Shortly after, after having seen the success of this innovation, the interface will be augmented with a feedback loop: workers will be able to see and hear thru the machines, to be even more efficient. After that, in order to boost efficiency and cut down on slack, the corporate will introduce a new feature - a mild electrical shock - to disincentivize unproductive behavior. After a few more such "improvements", the workers will live in a VR, bedridden, with their "reality" carefully mapped to their box pickup bots. Cogs in a machine won't be just a metaphor. There is no bottom in this descent: some even argue that your consciousness can move to such a machine, quite literally, and get trapped there.
Humans sooner or later become guinea pigs. Wohoo, what a nice outlook for society. Early adopters of machine interfaces will be the first generation of monkeys and rabbits for these companies and late adopters.
my theory is that the only way to explore the universe is to turn ourselves into machines. the distances don't look that menacing when you can turn yourself off for the duration of a millennial trip. space required in a "spaceship" suited for machines only would also be minimal, and life support wouldn't be needed.
this would also make an interesting sci-fi book :)
Yeah, but if I could choose, I'd rather modify myself biologically, than inserting some rigid, totally alien thing into my body. To be honest when these kind of advancements will be available humanity will already be fucked. I'd rather not live in an environment where this kinda thing is widespread.
Read the Takeshi Kovacs books, especially the first one (Altered Carbon), that explores this area.
27 comments
[ 3.1 ms ] story [ 28.4 ms ] threadThe last few decades have witnessed unprecedented convergence between humans and machines that closely operate around the human body. Despite these advances, traditional machines made of hard, dry and abiotic materials are substantially dissimilar to soft, wet and living biological tissues. This dissimilarity results in severe limitations for long-term, reliable and highly efficient interfacing between humans and machines. To bridge this gap, hydrogels have emerged as an ideal material candidate for interfacing between humans and machines owing to their mechanical and chemical similarities to biological tissues and the versatility and flexibility in designing their properties. In this Review, we provide a comprehensive summary of functional modes, design principles, and current and future applications for hydrogel interfaces towards merging humans and machines.
Overview:
The main challenges of human–machine interfaces stem from materials. Existing machines largely employ conventional materials, such as metals, silicon, glass, ceramics and plastics, to communicate and interact with human bodies. However, the hard, dry and abiotic nature of these conventional materials is intrinsically contradictory with the soft, wet and living nature of biological tissues. In recent decades, intensive efforts have been devoted to transforming these conventional materials into flexible and stretchable structures to conformally interface with soft and curvilinear biological tissues. However, these structural designs do not alter the materials’ intrinsic properties, which may still hamper their communication and interactions with biological tissues. For example, the integration of conventional materials with tissues usually relies on physical attachment or surgical suturing, methods that face challenges such as non-conformal contact, unstable adhesion, tissue damage and/or scar formation. As another example, the properties of metallic electrodes, such as their high rigidity, low interfacial capacitance and low charge injection capacity, make them far from ideal for the electrical recording and stimulation of soft neural tissues. In addition, biological tissues often recognize these materials, even when in flexible and stretchable structures, as foreign bodies due to their inherently disparate properties, resulting in an adverse foreign-body response, biofouling, and fibrotic encapsulation or fibrosis. Such foreign-body response and subsequent fibrotic isolation from the surrounding tissues can severely compromise the long-term reliability and efficacy of the communication and interactions between humans and machines.
Because of their unique similarities to biological tissues and the versatility and flexibility in tailoring their properties, hydrogels have naturally emerged as a promising material candidate to act as an alternative or adjunct to conventional materials for bridging humans and machines.
I was a competitive swimmer in high school. We had practice twice a day, and would always get pissed whenever we got a paper cut.
Because we never let the cut fully dry out and have a scab form, small cuts would take MONTHS to heal, and often result in scars when they shouldn't have.
Because of that I always assumed, dry conditions were ideal for healing.
New tissue growth is like the rest of our biology. Proteins are made in water solution inside cells. That has to get to the new tissue. Providing a scaffolding with a warm, wet, nutrient-rich environment around the wound should in theory make it heal faster and with less scarring, too. But these environments are also good for pathogen growth and invite infection. And removing detritus and pus and nutrient/gas exchange become issues as well. So just how moist and packed to keep a wound, and with what kind of packing and moisture, has been debated back and forth basically forever.
I see hydrocolloid bandages in pharmacies/groceries a lot nowadays, so hopefully they’re helping modern swimmers avoid the pain you went through!
1. Neither Synchron nor Neuralink have adopted anything resembling this in their R&D stack (despite the hype and wild claims being around for 15-20 years). 2. Instability is a major concern. And the target application (surgical/augmentation) wouldn't compromise stability for...conformation. Impedance data on such devices are very much humidity-level dependent. 3. Soft matter degrades. Especially if it gets heated by nearby electronics or when subjected to HF signals (brains/synapses are >1kHz). As it does, its properties change. 4. Ionic diffusion will mess with your interface in vivo. It's just the way nature works.
Nature created a journal dedicated to reviews in materials science this year. That was the news for me.
the title is slightly misleading. it suggests content focused on the neuralink, brain-computer interface whereas the article is more of a general overview of all applications, including ephemeral ones like epidermal and wearable applications and ingestible diagnostics.
ephemeral ones seem more promising, especially in the near future.
could you also elaborate on the benefits of micromachined electrodes/meshes?
The current state of a fast changing R&D group shouldn't be used to predict future state, especially when there's nothing close to a final product. They specifically talk about the problem of scar tissue, how biological films may be required, and how research is ongoing, here: https://youtu.be/YreDYmXTYi4?t=7009
>1. Neither Synchron nor Neuralink have adopted anything resembling this in their R&D stack
The current story with Neuralink monkey deaths calls into question how superior that tech is.
The movie "surrogates" explores this a bit (not a particularly good movie though).
[1]: https://www.nplusonemag.com/issue-44/essays/human_fallback/
[2]: https://scienceinfo.net/japan-makes-giant-construction-robot...
this would also make an interesting sci-fi book :)
Read the Takeshi Kovacs books, especially the first one (Altered Carbon), that explores this area.