Submission Statement:

Hyperloop technology is a proposed ultra-high-speed mode of transportation that could revolutionize how people travel, offering speeds of up to 700 miles per hour with minimal carbon emissions. In this Interesting Engineering interview with the president of HYPED, a student initiative dedicated to making hyperloop technology a reality, we learn about the cutting-edge technology and prototypes being developed, as well as the potential benefits and obstacles to the hyperloop's implementation. From reducing long-distance traffic to acting as a transportation safety net during natural disasters, hyperloop technology has the potential to transform how we live and move, and it's exciting to see how student-led initiatives like HYPED are driving the technology forward.

Birgül here again!

A huge THANK YOU to everyone for the great questions! I enjoyed so much answering them! I tried to answer as much as I could, but I couldn't get them all. If you want you can follow me on Twitter for further questions: https://twitter.com/akolpoglu

Cheers,

/birgül

What an interesting question!

I am a researcher at one of the many Max Planck Institutes in Germany, and the Max Planck Society (MPG) is mainly financed by public funds from the federal government and the federal states. Therefore, all research done within the MPG is published as scientific articles in journals and conferences and they are 100% open to the public. Some publishers have a paywall, but virtually all research and results can be accessed. I wouldn't know if anybody is out there reading these papers for a specific reason other than gaining scientific knowledge from them! :)

Thanks and hope this answers the question!
All the best,
/birgül

In addition to motility and engineerability, (both very important, most probably the most key features you need in this system) bacteria can sense and respond to changes in their local environment, providing a higher level of autonomy (such as chemotaxis, pH taxis and even magnetotaxis in the case of magnetotactic bacteria). Their size is also an important feature, being in the sub-micron to 2-3 micrometer range helps for better tissue filtration.

It is definitely not limited, and other bacterial species are currently being used in such studies as well. Especially prebiotic and probiotic bacteria (e.g., E. coli Nissle; EcN) is a promising strain as well.

I didn't get into the specific role of bacteria in cancer therapy but here is my all-time favorite review paper on the subject, where you can find out more about the use of various bacterial agents in cancer immunotherapy!: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4802035/pdf/IJMICRO2016-8451728.pdf

All the best,

/birgül

It is not dragging but rather aligning them. So what happens is that the nanoparticles on bacteria align with the applied magnetic field. Therefore, bacteria follow that path. We could also create so-called "magnetic gradients", which would cause dragging or pulling. But we want to use their own motility rather than pulling them.

As for the second question: No, they don't. We use electromagnetic coils (see: https://www.sciencedirect.com/topics/engineering/electromagnetic-coil) that generate enough magnetic field in the center of the setup to steer the microswimmers. These setups are designed for microscopic use, i.e., we attach them to a microscope to simultaneously visualize the motion of bacteria under magnetic fields. Of course, you would need much larger setups for use in humans in the future, but even in that case, it wouldn't be in contact with the body.

Thanks for the Qs!
All the best,
/birgül

This is a very important question! This is exactly why we are opting for a system that is active and externally controllable. Using a tiny machine that can be selective towards non-healthy tissue, that can be externally controlled to accumulate in a specific location (i.e., tumor) and that is equipped with an on/off switch to release its cargo on-demand are all the desired features in bacteriabots. This way, you minimize the side effects on non-target healthy cells. Realistically, it is almost impossible to cause no harm to a healthy cell even with an active controllable system. In that case, our bodies have defense mechanisms (immune system) that can fight unwanted agents. It is crucial to make sure that the bacteriabots are safe for administration below a certain dose and that they are not causing any pathological response.

All the best,
/birgül

Merhaba!

As I mentioned in another answer, bacteria should be removed from the host body after the medical task is completed, therefore another concept, which is named termination switches, could be also added to bacteria to terminate them after they had carried out their task through laser-triggered hyperthermia, antibiotics or bacterial lysis. If no such mechanism to remove them is in place, you would expect them to be neutralized by the immune system (granted that they are below a pathological dose). Since they are of cellular material, they are also fully biodegradable.

All the best,
/birgül

P.S.: I actually have a Turkish keyboard!

Thank you for your questions. Depending on the size and location of cancer, we would need millions to more than billions of them to localize and generate enough therapeutic effect.
Yes, they reproduce and multiply, which can be undesired for biohybrid bacterial agents, because reproducing means dilution of the synthetic components. That means new bacteria without enough magnetic material on them, causing loss of steerability. However, there are genetic tools that stop microorganism growth, which could be ideal here. Reproducing should also be under control because your injected dose could be in the millions range, but you could easily reach billions within a matter of hours, since the duplication time of microorganisms can be just minutes (e.g., around 20 minutes for E. coli). Additionally, bacteria should be removed from the host body after the medical task is completed, therefore another concept, which is named termination switches, could be also added to bacteria to terminate them after they had carried out their task through laser-triggered hyperthermia, antibiotics, or bacterial lysis.

All the best,
/birgül

Thanks for the question! Although I am no expert in bioremediation, I know that several large-scale wastewater treatments with microalgal technologies have already demonstrated the capability of detoxifying organic and inorganic pollutants. Microalgae can remove contaminants through three different pathways; bioadsorption, biouptake, and biodegradation. For further information I would recommend these publications:

https://aiche.onlinelibrary.wiley.com/doi/epdf/10.1002/btpr.3098

https://pubmed.ncbi.nlm.nih.gov/31382151/#:~:text=Microalgae%20have%20demonstrated%20potential%20for,%2C%20bio%2Duptake%20and%20biodegradation

Our research on microorganism based microrobotics mainly focuses on their medical functions, but I am always interested in finding out more on other uses of these tiny swimmers!

Hope I could answer your question!

All the best,

/birgül

Thank you for this interesting question! If we come to a point where these biological nano or microrobots are used in clinics, the treatment of hospital waste would technically become a concern. Once out of the body, the bacteria-based microrobots described in our study could easily be disposed of by sterilization techniques, such as using a detergent solution or by simply heating to sterilize. So you basically treat it as any other hospital waste.

I mentioned in another answer, so I am repeating that bacteria should be removed from the host body after the medical task is completed, therefore another concept, which is named termination switches, could be also added to bacteria to terminate them after they had carried out their task through NIR-triggered hyperthermia, antibiotics or bacterial lysis. THis way once the agents are outside of the body, they are already harmless.

Hope this answers your question!
All the best,
/birgül

Thanks for the question! In contrast to their synthetic counterparts, biological nano- or microrobots can sense and respond to changes in their local environment, providing a higher level of autonomy. Also, most microorganisms can achieve high propulsion speeds (tens of their body lengths per second) and interact with their targets at the same size scale (1–10 μm). Such advantages make biohybrid cellular microrobots attractive candidates for medical applications, including targeted drug delivery. These are the main advantages, however, this is not to say biohybrid microrobots are always superior to synthetic ones since the selection of the micro and nanobots is highly application dependent.

All the best,
/birgül

There are many technical challenges. All the synthetics parts that you want to equip your bacteria with should add an extra function to your swimmer. For instance, in our case, magnetic nanoparticles are added for swimming control using external magnetic fields, and nanoliposomes loaded with drugs are added for the demonstration of on-demand, localized drug release. One needs to carefully choose these synthetic components for the desired application, and design them accordingly. They need to be compatible, non-toxic, ideally smaller than your microorganism, and fully functional. Also, your microorganism should be able to accommodate the attachment of these synthetic cargoes. We use something called “biotin-avidin” interaction to equip bacteria with the components, and this had previously required the genetic modification of bacteria to express “biotin” on their cell surfaces, which is not a simple task either. Microorganisms also shouldn’t stop swimming after the addition of the synthetic components, because we want to harness their motility for active therapeutic applications.

Overall, designing a tiny robot out of a living, motile microorganism requires extensive planning and design on material development, genetic engineering, microscopic imaging, and viability checks after modifications and testing of their functions after the construction is complete.

Thanks for your question!
All the best,
/birgül

Hi! Oh, I would love that, that could make life MUCH easier if bacteria could listen to the voice of reason! But no, we do it pretty scientifically!

In our work, the synthetic components were integrated onto Escherichia coli. We use a strain of E. coli that allows for one-step binding of such nanoparticles through a physical complex known as “biotin-streptavidin complex”. Basically, these bacteria have “biotin” protein that binds to the “streptavidin” protein that is on the surface of the nanomaterials we use here. We mix them together under certain conditions (temperature, shaking, and the type of liquid media are all very important), et voilà, your bacterial biohybrid microswimmers are ready.

Thanks for the Q.
All the best,
/birgül

Thanks for your question! We attach nanomagnets on E. coli and control them using bigger magnets (centimeter scale) or electromagnetic coils for precise steering. Magnetized bacteria still swim using their flagellar propulsion, but follow the magnetic field lines, therefore making it possible for us to control them externally using magnetic fields.

All the best,
/birgül

These are very interesting questions! Let me try to answer as much as I can.

As I mentioned in a previous question about “how close we are to using these medical tiny robots in clinics”, currently this technology is not there yet. There are many, many promising studies with animal models, for example, showing the localization of microrobots on tumor tissues for targeted drug release. Nevertheless, we still need extensive research on other aspects including safety, imaging, tracking, and controlling of these robots. Therefore, I cannot exactly give you numbers, since they are currently not commercialized.

As for the second question, the biggest concern would be safety. If the material(s) used in the robotic design is immunogenic, there is already the risk of an immune reaction. This could not only eliminate your tiny robot before it can do its job but also generate a health risk. Additionally, let’s say you plan to administer your robot through the circulatory system, then the size and shape of the robot are crucial since you wouldn’t want the clogging of the vasculature.

And for the last question, I haven’t played the game or seen the show (yet), but I am currently reading a book on fungi (it’s called Entangled Life: How fungi make our worlds, change our minds and shape our futures, by Merlin Sheldrake, it’s a super cool book, 100% recommend) and just recently found out about Ophiocordyceps unilateralis, aka zombie ant fungi. The mechanism of taking control over an ant compared to a human is drastically different. Turning people into “zombies” is rather sci-fi than science, but many organisms (viruses, bacteria, fungi, parasites, etc.) do have an enormous impact on human life that we cannot disregard.

All the best,

/birgül

Thank you for your questions. Here in our study, what happens is that we attach nano-sized magnetic particles to bacteria, and therefore, we are able to control those bacteria using external magnetic fields. You can imagine a single bacterium turning into a tiny magnet that can be navigated using a larger magnet, or electromagnetic setup. As for the colonies, with our optimized method, we were able to generate millions of these bacteria (we call them bacterial biohybrids), carrying the magnetic nanoparticles, meaning that we were able to control the swarms of bacterial biohybrids using external magnetic stimuli. Magnetic control mechanisms are quite robust since magnetic fields are safe to use in clinics and it allows for precise control over tiny swimmers. We can technically “steer” them using our electromagnetic coils, they go right when you press right, and go up when you press up on the control panel!

Hope this answers your questions!
All the best,

/birgül

Hi! I am no expert on genetics since I am trained as a Chemical Engineer, I may not be able to answer your question fully. As far as I know, genetic drift cannot be stopped from occurring since it is an event based on random chance. In bacteria, we can rather talk about mutations, which would happen over a long period. In our case, the envisioned therapy is very short term: injection, therapy, and removal. Therefore, current projections do not give us any reason to be concerned about the possibility of bacterial genetic drift or mutation.

All the best,
/birgül

Thank you for your question!

To be able to reach that point, where we can safely administer medical micro- and nanorobots to human bodies to carry out various medical tasks, some challenges remain to be tackled.

Firstly, the micro- or nanorobot should be safe for injection – meaning it should be biocompatible for its application, and should still be actively controllable to target specific regions. This requires extensive research on material development, safety tests, and wireless control mechanisms (such as magnetic fields, light, acoustics, etc.). Currently, hundreds of different medical micro and nanorobots are tested on Petri dishes and animal models, and many promising candidates could perhaps one day turn into clinical success.

However, that is not the end of it. Once your tiny robot is good to go, then we need real-time medical imaging techniques to be able to precisely detect and visualize these robots inside the body. Currently, many imaging systems are developed to increase the resolution and overcome the imaging limits such as our tissue penetration depth. Another important aspect that is commonly overlooked is the removal or elimination of the biohybrid microrobots after the treatment. Approaches regarding retrieval of the microrobots should be investigated as well. Additionally, active control mechanisms should be scaled up for human use, since currently reported setups are mostly designed for proof-of-the-concept studies and small animals.

We need many more in vivo and then pre-clinical studies that rigorously investigate the feasibility of these tiny robots. Therefore this is currently not a “ready-to-use” technology that our society can benefit from when it comes to treating patients, however, it holds great promise, and considering the exponential increase in the research of nano- and microrobots to overcome mentioned challenges, it is not far-fetched to imagine the use of medical robots in clinics in the future.

All the best,
/birgül

Hello everyone! Birgül here.

First of all, thanks for all the amazing, interesting, and stimulating questions! I am now online and will try answering as many questions as I can within the next hour!

In the meantime you can check our recent work on bacterial biohybrid microrobots here: https://www.science.org/doi/full/10.1126/sciadv.abo6163

Also, here is my Twitter: https://twitter.com/akolpoglu

All the best,

/birgül

Thanks everyone for participating and for the questions! Unfortunately, I have to run to a meeting but I enjoyed getting to share a little bit about our work.

-JRS

I'm not a medical doctor so I can't say for sure but it sounds like you are having a reaction to something in the tattoo and should maybe talk to a dermatologist. Since we don't know what causes allergic reactions in some tattoos it's entirely possible that you are allergic to some pigment in the problem tattoo and that the pigment is present in other your other tattoos. However, that's only speculation on my part. -JRS

Right now for quantitative purposes, microwave digestion and ICP-MS. For more qualitative purposes, X-ray fluorescence and/or EDAX. Most of the colored pigments are "organic" or molecular. There are some exceptions like iron oxides in browns and some reds. Black pigments are mostly carbon black and white is most TiO2 or barium sulfate, which would be considered "inorganic" or solid pigments. -JRS

Probably slim! -JRS