The nanoprobes assimilating various species in the movie Star Trek: The Next Generation may give goosebumps or nightmare. How can someone predict where science and technology can lead us? The most successful attempts to predict the fate of mankind are those of the science fiction writers like Jules Verne, Issac Asimov and Arthur C. Clarke. I would not be wrong to claim that nanofiction has played a very crucial role in pushing human imagination and thus, human endeavour.
However, Eric Drexler is known as the ‘Father of Molecular Nanotechnology’. Drexler’s Engines of Creation (1986) is an enormously original book about the consequences of new technologies. It is ambitious and imaginative, and best of all, the technically sound. In this book, he asks, “What can we build with the atom stacking mechanisms?”
Nanobots in Popular Culture
There are several examples where nanotech gadgets, especially nanobots, have found implementations in popular culture. The Next Tenants by Arthur C. Clarke describes tiny machines that operate at the micrometer scale. T-1000 in ‘Terminator 2: Judgement Day’ is a nanomorph that was created using programmable nanotechnology. The Trinity series features an alien nanomachine found on Mars. In the movie ‘Prey’, a swarm of nanorobots develop intelligence and become a potential threat. In 2009 movie, G.I. Joe: The Rise of Cobra, the main plot is to save the world from a warhead containing deadly nanobots called ‘Nanomites’, which if detonated in a city could destroy it in hours. In Total Annihilation, a video game, nanobots are used to build structures.
What is a nanobot?
Nanobot can be synthetic or biological. As of now, no research group has been able to come up with a non-biological nanobot. It still remains a hypothetical concept. Most of the existing nanobots are in fact biobots and the recent advancements in this field have been promising. DNA and bacteria usually range in 2.5 nm and can be used as biological entities to create biological nanobots.
Applications of Nanobots
1. Nanobots in Drug Delivery
DNA Nanobots delivering drugs in living cockroaches is not a myth. Just imagine a computer inside a cockroach. Nanoscale entities made of DNA that can perform the same logic operations as a silicon-based computer have been introduced into a living species. Bioengineers at the Wyss Institute in Harvard University have achieved this sophisticated advancement with the goal of sophisticated disease diagnosis
Biological systems are a collection of discrete molecular objects that move around and collide with each other. Many of the cell processes are intervened or initiated by these collisions. Now DNA is a substrate that has previously been used in computing and robotics. Researchers at Wyss Institute used DNA origami to fabricate nanoscale robots. So, these DNA based origami robots are biocompatible and thus can influence cell processes when they collide with another DNA or cellular micromolecules inside the living animals like a cockroach in this case.
The nanobot control can be simplified as a locked door containing chemicals with keys lying with the externally infused DNA nanobots. Cockroach (Blaberus discoidalis) was chosen for the initial prototype of the nanodevice because of its low systemic nuclease activity, small systemic volume and chemical compatibility with DNA structures.
Nanobots can be useful in cancer treatment because they can be programmed to target specific cancer cells. A team of scientists at Israel’s Bar-Ilan University have gone a step further in 2016 to start human trials of DNA based nanobots to fight cancer. The DNA nanobots enclose drugs and as soon as they interact with cancerous cells, they release the drugs.
2. Nanobots as Respiratocytes
Nanobots can act as respirocytes. Respirocytes are artificial red blood cells that can emulate the function of RBCs. Respirocytes can be used in the treatment of anemia, heart attack, and lung diseases. Molecular manufacturing promises precise control of matter at the atomic level. Dr. Robert Freitas proposed a 1-micron diamondoid 1000 atm pressure vessel with active pumping powered by endogenous serum glucose that can deliver 236 times more oxygen to the tissues per unit volume than natural red blood cells. In a research paper titled “Exploratory Design in Nanotechnology: A Mechanical Artificial Red Cell (1998)”, he talks about controlling the artificial RBC using nanocomputers that can be programmed using acoustic signals. Nanocomputing is in itself a great revolution that promises very fast computations.
Once a therapeutic purpose is completed, it is desirable to extract artificial devices from circulation. Onboard water ballast control is extremely useful during respirocyte exfusion from the blood. Blood to be cleared may be passed from the patient to a specialized centrifugation apparatus where acoustic transmitters command respirocytes to establish neutral buoyancy.
3. Nanobots in Pollution Control
4. Nanobots in Diagnosis
5. Nanobots as Clottocytes
These nanobots can mimic the natural process of hemostasis. Hemostasis is a process that causes the blood to stop. It is the first step of wound healing and involves coagulation.
Limitations of Nanobots
The unique properties of nanoscale materials (1-100nm) offer an excellent platform for the design of a new generation of biosensing and bioelectronics devices. However, the biocompatibility of the nanomaterials is at the forefront of research for quite some time now. Synthetic nanobots are still a hypothetical concept. Silicon is definitely a top choice for the construction of the nanobots. It is durable, flexible and conducts electricity. However, it will not dissolve in the body fluids.
The controlled mobility of the bots inside the living organism for most medical applications is another issue.
“There is plenty of room at the bottom” was a lecture given by physicist Richard Feynman at Caltech on December 29, 1959. Feynman considered the possibility of direct manipulation of individual atoms as a more powerful form of synthetic chemistry than those used at that time. The talk, however, went unnoticed and didn’t inspire the conceptual beginnings in the field.
In the 1990s, it was rediscovered and publicized as a seminal event in the field. So, I must say that people before Drexler have also imagined the power of nanotechnology. It is the vision of the futurists like Feynman and Drexler that research in concepts like nanobots has got the impetus and with further development, they will forever change the field of medicine in the coming days.