Robots: Nanobots: Why should I care?

When I started my research of nanobots, I was prepared to write a blog post akin to my analysis of slaughterbots –– a cautionary tale of novel technology with nefarious applications. I had this image in my head of an evil villain, supported by a microscopic army of nanobots, poised to systematically wipe out large swathes of the population. SPOILER ALERT! I was probably relying too heavily on the new James Bond movie for information. Or maybe, my preconceptions were fueled by residual memories of G.I. Joe: The Rise of the Cobra. Though, its 33% score on Rotten Tomatoes suggests I may do better to forget it entirely… Below, you can see the killer nanobot from the movie.

While I’d love to unpack this more, I think the time would be better spent describing two recent applications of nanobot technology. First, let’s dig into the use of nanobots’ as cancer-fighting agents. Then, I want to explore a very recent discovery, Xenobots, which have been deemed the world’s first living robots. What’s more, they can even reproduce!

Nanobots and Chemotherapy

Nanoid robotics, shortened to nanorobotics, is the field that creates robots that are approximately one nanometer in size. Currently, these robots are in the research and development stage, yet promising results in medical studies forecast a bright future for this budding technology. One of the most researched applications of nanobots is as a Drug Delivery System (DDS). 

There’s a big problem with chemotherapy. As it stands, it’s non-specific, meaning that both malignant and healthy cells are targeted indiscriminately. However, scientists are now working with organic nanobots, known as bio-nanorobots, to target malignant cancer cells. In one study, researchers have been able to coat a nanoparticle, made of a component found in our bones, with paclitaxel, a common chemotherapy drug. Because the nanoparticle is already present in our bodies, this method does not have the same risk as introducing an inorganic nanobot into our systems. Essentially, instead of pumping toxic chemicals into a cancer patient’s blood stream, these researchers want to use nanobots as organic homing missiles directed at cancer cells. This breakthrough would greatly reduce the infamous side effects of chemotherapy, like hair loss, bone marrow density reduction, gastrointestinal issues, etcetera. Luckily, the study has proven this method of drug diffusion to be successful in eliminating malignant cells. There’s one big hurdle, however. These researchers are still refining the method they use to target only malignant cells. Hence, this technology is still in the research and development phase. I attached the graphical depiction from the study below. While it is highly technical, I think you will get the gist.

In an ongoing study, Swiss researchers are looking to deploy this specific chemotherapy delivery system against inoperable cancers, such as glioblastoma (a rare brain tumor). First, they form a polymer shell around an air bubble that is filled with bio-nanorobots. These nanobots are coated in a chemotherapy drug. Visible in the blood stream, the researchers can guide this cluster of nanobots via ultrasound to the location of the tumor. Ultrasound emits “high-frequency sound waves” (Wild et al.) that are strong enough to move these small nanobots, while not affecting red-blood cells. The lead researcher, Professor Daniel Ahmed, gained inspiration for these “nanoswimmers” by studying how sperm move. Just as sperm follow along the vaginal wall, his nanobots navigate along vascular walls. When the nanobots reach the tumor, they can then deploy the drug to kill the cancer cells. Thanks to nanobots, previously terminal cancers may be eradicated. The jury is still out, as we are still very much in the early stages of nanobot medical studies. However, these two studies should be reason enough for optimism. The figure below is an example of how nanobots penetrate the cell wall of cancer cells and deliver chemotherapy drugs.

Xenobots

Now, I want to turn your attention towards Xenobots. Originally, I didn’t think any nanobot could be more interesting than microscopic cancer-fighters, but Xenobots might have them beat. Bear with my analysis, this research paper was dense, and I’m not a STEM major.

Thinking back to high school Biology class, remember that “living systems perpetuate themselves via growth, followed by splitting, budding, or birth” (Kriegman et al). In fact, up until this study, scientists believed that all multicellular organisms used a growth method for reproduction. That is, until a research team from Tufts, Vermont, and Harvard discovered otherwise. This team took thousands of prospective skin and heart cells from a frog (Xenopus laevis) and put these dissociated stem cells in a petri dish. With a saline solution, the researchers assembled clumps of these stem cells and placed them in the same dish. These clumps of ~3,000 cells were then free to interact with the ~60,000 individual stem cells.

Soon, the cell clumps began using their hair-like cilia to move in helical patterns. Astonishingly, these clumps began molding the dissociated stem cells into replica clumps, in a process deemed kinetic self-replication. They replicated by moving, not growing. Please click on the link below to watch these clumps replicate.

https://wyss-prod.imgix.net/app/uploads/2021/11/29113655/BlackistonV12-copy.gif?w=1200&h=672&auto=format&q=90&fit=crop&crop=faces%2Centropy

Why is this important? These researchers made no changes to the genetic makeup of these frog stem cells. On their own, the stem cell clusters used their collective intelligence to reproduce in a method previously reserved for organisms of the lowest complexity––via movement. Here’s where the robotics part comes in.

Then, using a supercomputer, the researchers algorithmically determined the cell-clump shape that led to the most self-replication. Funny enough, this optimal shape closely resembles a Pac-Man. Using their Pac-Man mouths, they can best clump together the lone cells into new PacMen. By manipulating the starting formation of the cell clump, the researchers extended the reproductive cycle from two generations of offspring to four generations. The research team was able to use AI to influence the reproductive behavior of these organic nanobots. If we take the definition of a robot to be “a machine capable of carrying out a complex series of actions automatically, especially one programmable by a computer” (Oxford Dictionary), then Xenobots satisfy the requirements of being robots.

In summary, a supercomputer-designed clump of cells, with no genetic imperative to engage in self-reproduction, acted as a team to “spontaneously replicate.” Or, in the study’s less congratulatory words, “Given their rapid loss of replicative ability, reconfigurable organisms can be viewed as autonomous but partially functioning machines potentially amenable to improvement” (Kriegman et al). Below is the graphical representation of their algorithm’s results for the clump shape that yielded the most offspring. Please click on the image to enlarge.

One of the researchers, Josh Bongard, explains that “This is an ideal system in which to study self-replicating systems. We have a moral imperative to understand the conditions under which we can control it, direct it, douse it, exaggerate it.” He hopes that further study of Xenobots can yield effective remedies for humanity’s greatest threats, like disease and climate change. Studying the behavior of these biological robots, he hopes we can leverage machine learning to find solutions to problems that take humans too long to solve, like the COVID-19 vaccine. He hypothesizes that with precise human-inputted parameters, the supercomputer could output a biological tool to combat the next pandemic or remove microplastics from the ocean. Of course, Bongard is not implying that this technology is around the corner. But, with such a substantial scientific breakthrough, the limits of what Xenobots and related bio-nanobots can teach us are still unknown.

Conclusion

At the very least, I hope this blog has been able to persuade you that further research into nanobot technology is warranted. The early advancements in the field are enough to get even a layman, like me, excited to read future nanobot studies. There’s no way of knowing how self-replicating frog stem cells might help us solve the issue of microplastics in the ocean, or how cancer treatment may change in the next quarter century with further development of bio-nanobots. But, as I reflect back on all that I’ve read, there does seem to be a linchpin for these studies. They all describe a future made brighter by the existence of nanobots, and that’s enough for me to buy in.

— Charlie Thorne

Sources:

https://www.cureus.com/articles/108503-the-use-of-nanorobotics-in-the-treatment-therapy-of-cancer-and-its-future-aspects-a-review#:~:text=A%20nanorobot%20can%20aid%20with,chemotherapy%20drugs%20so%20being%20used.

https://doi.org/10.1016/j.actbio.2012.11.013

https://doi.org/10.1073/pnas.2112672118

https://ec.europa.eu/research-and-innovation/en/horizon-magazine/nanorobots-could-target-cancers-and-clear-blood-clots

Team builds first living robots—that can reproduce

https://www.google.com/search?q=robot&oq=robot&aqs=chrome.0.69i59l2j0i433i512j0i131i433i512j46i131i433i512j0i131i433j0i131i433i512j69i61.1269j1j9&sourceid=chrome&ie=UTF-8

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