Nanorobots are poised to transform medicine

IEC E-tech

article here 

While specific standards will be required for nanobots, some technical committees have published documents in adjacent areas. Find out more about the tech  advances enabled by these minute devices, notably in the medical domain.

Sixty years after the release of the film Fantastic Voyage, science is finally going beyond fantasy with nanorobotic agents designed to traverse thousands of kilometres of vessels inside a living being, delivering drugs directly to lungs, brain or heart.

“We are using MRI scanners to navigate tiny therapeutic particles inside the body, effectively treating them like microrobots,” says Professor Sylvain Martel of the Department of Computer Engineering and Software Engineering at Montreal Polytechnique. “We can see where they are and control their trajectory using magnetic fields.”

The global nanobotics market was worth USD 9,1 billion in 2024 and is projected to hit USD 20,45 billion by 2030 with biomedicine the biggest industry driving demand. “For liver cancer, for example, we plan to introduce these particles through the hepatic artery, similar in concept to Fantastic Voyage,” says Martel. “Results are very encouraging.”

Nonetheless, the technology has yet to make it out of the lab and move on from animal trials. It is still early days and the tech is far from being produced on a wide scale. Nanorobotics holds huge potential for targeted drug delivery, but transferring the technology for human clinical use is not straightforward.

Micro or nanorobotics?

Nanorobotics itself refers to the emerging field of science and technology that deals with the design, development and control of robots at the nanoscale. In medical research and articles about advances in this area, however, the term nano and micro are used interchangeably. The term “nanomedicine” has been used for at least 15 years to describe the use of nanorobotics for performing tasks typically requiring invasive microsurgery.

At its simplest, nano and micro are measures of size. The nanoscale ranges from 1 to 100 nanometres, where one nanometre (nm) is equal to one billionth of a metre. This size is comparable to the width of a DNA molecule. A micron or micrometre is 1 000 times bigger than a nanometre and measured in μm, where 1-10 μm is the length of a bacterium.

“We often say ‘micro–nanorobotics’, but when you look at nature, the organisms that actually move – bacteria, paramecia, sperm cells– aren’t nanoscale. They’re microscale,” explains Dr Bradley Nelson, Professor of Robotics and Intelligent Systems at ETH Zürich. The body of E. coli, for example, is one to two microns in diameter, with a tail about 15-20 microns long that rotates to propel it. Sperm cells are of similar size.

When researchers build robots that they can control in a living body, they do so at the microscale, because anything smaller is susceptible to Brownian motion. “Below about a micron, random atomic impacts dominate,” Nelson explains. “Directed locomotion becomes much harder and less effective. That’s why nature evolved microscale propulsion systems, like the rotary motor in bacteria or the beating flagella in eukaryotic cells. So, for controllable movement, microscale is often the sweet spot.”

Robots the size of red blood cells

Nanorobots may conjure up images of tiny, controllable mechanical objects, and these attributes still apply in medicine. Research is inspired by the ability to use the robot-like characteristics of DNA, bacteria or other biological substances to transport and release drugs with greater efficacy than other surgical procedures. 

Bacteria were first observed in 1675, yet it took nearly 300 years to discover that they swim using a rotary motor. Inspired by this, scientists began studying the fluid dynamics of bacterial locomotion and exploring how nanotechnology could replicate some of these mechanisms. Researchers such as Howard Berg (who helped uncover the rotary motor mechanism of flagellated bacteria like E. coli and Salmonella) have described bacteria as nature’s “microrobots”.

Nelson explains, “These organisms are typically one to two microns long and have chemoreceptors that function as sensors, a rotary motor that drives their flagellum and a signalling pathway that determines whether they are moving in a favourable direction. DNA and plasmids act as ‘onboard software’, controlling protein production. In many ways, they truly are autonomous robots.”

Fabrication methods have advanced from materials such as gallium arsenide and indium gallium arsenide to polymer-based structures using nanoscale 3D printing systems. These devices are 5 to 10 microns in length, comparable in size to a red blood cell.

Standards are tackling miniaturization

While these are very far from being nano, the IEC has developed most of the standards used for motors, including the very widely employed IEC 60034 series of international standards. Some principles in these specs could probably be adapted to microscale requirements, although this remains to be seen and is very much in a future realm.

IEC TC 47 has set up a specific subcommittee to standardize micro-electromechanical systems (MEMS) – miniaturization being a huge trend in electronics. Among its standards, the IEC 62047 series specifies a number of performance tests for micromaterials. IEC TC 40 Chair, Markus Schwerdtfeger, explains how miniaturization is changing the name of the game for his TC and for many others. TC 40 produces standards for capacitors for electronic circuits. “Components are becoming microscopically small, yet they must deliver the same or even higher levels of performance. For TC 40, this means enormous challenges, especially regarding thermal management and reliability in the tightest of spaces. We have to continuously adapt our testing procedures for these tiny surface-mount devices (SMD).” Read the full interview in e-tech.

IECQ, one of the four IEC Quality Assessment Systems, provides an approved component certification scheme, which ensures small components are subjected to comprehensive reliability testing to ensure their performance under various conditions, such as temperature fluctuations, vibrations, and stress.

The joint technical committee formed between ISO and the IEC focusing on IT, ISO/IEC JTC 1, has published a number of standards relating to 3D printing, including for the medical world. The IEC has also recently set up a joint systems committee with ISO, to look investigate the area of bio-digital convergence. It should examine the requirements for standards in this growing area of tech.

Control and navigation using magnetic fields

Further questions address how nanobots are tracked and coordinated and whether and how they adapt to their environment. Actuation methods include chemical propulsion and light. Researchers have also explored acoustic propulsion using ultrasound. Most work has focused on using magnetic field gradients or rotating magnetic fields.

“Magnetic control offers biocompatibility, deep tissue penetration and precise external programmability,” says Nelson. To briefly review the physics: magnetic fields can generate both torques and forces on magnetic bodies. If a magnetic dipole – such as a microrobot made of iron, nickel or neodymium-iron-boron – is placed in a magnetic field, it experiences a torque that aligns it with the field. If there is a magnetic field gradient, the dipole experiences a force that moves it toward regions of stronger field.

“We typically generate these fields using electromagnets mounted on robotic arms. One major advantage of electromagnets is that nothing mechanical needs to move, aside from electrons flowing in the coils. By adjusting the current, we can change the field strength and direction instantly. In contrast, permanent magnet systems can generate stronger fields but require physically moving large magnets, which makes them slower and less flexible.”

Scientists are testing 300 nanometre magnetic robots for brain aneurysms. These tiny surgeons are guided by external magnets, cluster together at the problem site and release blood clotting proteins in seconds.  

Martel is leading a team developing a method that uses magnetotactic bacteria (MTB) that respond to magnetic fields. “These bacteria naturally migrate toward hypoxic (low-oxygen) environments like tumours,” he says. “Once guided near a tumour with magnetic fields, they autonomously move toward the hypoxic zones and deliver the therapeutic drug directly where it is needed.”

Medical standards for MRIs

This approach may be even more powerful than the MRI-guided particles because the bacteria act as self-propelled microrobots with built-in sensing capabilities. Martel explains, “We synthesize chains of magnetic nanoparticles inside the bacteria which act like a compass needle. By creating magnetic field gradients, we can orient the bacteria in a specific direction. Unlike pulling an object directly with magnetic force, we simply align the internal ‘compass’. The bacteria then propel themselves using their own molecular motors (flagella).”

Torque-based control requires much weaker magnetic fields, with more reliance on bacteria’s natural propulsion system. According to Martel, MTB are 10 times more powerful in propulsion than typical bacteria.

To implement such systems, the patient would need to lie under fluoroscopy. Surgeons see the capsule via X-ray and steer it using precisely controlled magnetic fields. “Strictly speaking, the ‘robot’ is the entire system – imaging, magnetic control, user input – not just the capsule,” Nelson says.

IEC TC 62 is one of two medical standardization committees inside the IEC. It has produced multiple standards for the safety of medical devices – notably X-rays. The IEC 62220 series specifies the different characteristics of X-ray machines.

IECEE, the IEC System of Conformity Assessment Schemes for Electrotechnical Equipment and Components, offers testing and certification for the safety, reliability, efficiency and overall performance of electrical equipment for medical use to IEC International Standards, whether new or refurbished.

IEC TC 113 outlines the standardization of the technologies relevant to electrotechnical products and systems in the field of nanotechnology - including nanomanufacturing - in close cooperation with other committees of the IEC and ISO. Still early days, but it could embark on the standardization of nanobot requirements.

Biocompatible materials: safety is paramount

It is critical that the materials used to manufacture these nano-microrobots are proven safe and non-toxic. “We must demonstrate safety within blood vessels with no harmful side effects and controlled biodegradation within a defined timeframe,” says Martel. “Even if navigation works perfectly, you still must prove that everything is safe for patients.”

Gold, titanium dioxide and biodegradable polymers such as polylactic-co-glycolic acid have emerged as preferred materials due to their established safety profiles in medical applications. Graphene flakes can be embedded into a hydrogel polymer to create structures that respond to infrared light. “The graphene absorbs infrared radiation, generates localized heating and triggers swelling in the hydrogel, enabling controlled shape change,” Nelson explains. “This allowed us to fabricate deformable microrobots whose morphology could be dynamically controlled.”

ETH Zurich have developed a microcapsule that comprised of a polymer gel matrix, iron oxide particles (so it responds to magnetic fields); tantalum (Ta), which shows up clearly under X-ray imaging; and a drug payload (such as tissue plasminogen activator for dissolving blood clots).

Nelson explains, “The iron oxide acts as the actuator, responding to magnetic fields. The tantalum allows imaging under fluoroscopy (X-ray). The drug performs the therapeutic task. The polymer matrix holds everything together and dissolves at the target site. The strongest magnets, like neodymium iron boron, are toxic. That’s why we use iron oxide. It’s safer, though less powerful.”

Regulatory approval is a hurdle

Because R&D in this emerging technology integrates biology, chemistry and robotics, as well as involves the medical treatment of humans, regulatory approval is complicated. “If one constituent isn’t approved for human use, you either spend enormous resources getting that part approved or reformulate the whole recipe,” Martel reports. “Reformulating can delay progress significantly. “We are approaching human trials, though I cannot give a specific timeline. We are not talking about 50 years – but regulatory approval takes time.”

Regulatory frameworks governing medical nanobot deployment are evolving to address unique challenges posed by these autonomous systems. The FDA, which regulates nanotechnology chemotherapy agents in the US warns that the “very changes in biological, chemical and other properties that can make nanotechnology applications so exciting may merit examination to determine any effects on product safety, effectiveness or other attributes.”

Researchers are exploring more programmable behaviour – such as altering magnetization in situ or adding logic elements. One solution involves coercivity, the magnetic “hardness” of a material.

“At the nanoscale, coercivity can be tuned by altering the shape of a structure,” Nelson says. “We can create structures with distinct magnetic anisotropies and coercive properties. Exposing the structure to magnetic fields of varying strengths and directions allows selective magnetization. This enables programming.” A stronger magnetic field might permanently magnetize one part of the nanorobot, while a weaker field magnetizes another part with lower coercivity.

“By designing specific magnetic domain patterns and encoding magnetization vectors in different directions, we achieved behaviours such as turning motions, hovering-like dynamics and distinct deformation patterns,” Nelson says. The fact that geometry and magnetic encoding together define behaviour opens fascinating connections to robotics concepts such as motion planning, complexity and control – now implemented physically at the micro-nano scale.

What application for oncology?

Targeted drug delivery using nanorobotics is particularly suited to cancer treatment because it overcomes a major limitation of chemotherapy; less than 1% of injected drugs actually reach the tumour. The rest circulates systemically, causing side effects. With around 85-90% of cancers in localized tumours, targeted delivery makes sense.

“Imagine putting a drop of ink in the middle of a swimming pool,” says Martel. “It won’t diffuse far enough to reach the edges. Tumour blood vessels deliver drugs only about 6-8 micrometres into tissue. But hypoxic tumour regions can be 80-100 micrometres away from blood vessels. By actively transporting drugs deep into those hypoxic zones, nanorobotics solves this diffusion problem.”

In 2024, researchers at Sweden's Karolinska Institute created DNA nanobots that hunt down cancer cells in mice. These robots carry a “kill switch” that only activates in the acidic environment surrounding tumours. The results: tumour growth significantly reduced with healthy cells left completely untouched. Nelson says, “Our hope with this technology is to carry very high local doses directly to the tumour – whether that’s breast cancer or a brain tumour like glioblastoma – while minimizing exposure elsewhere in the body.”

Use cases beyond biomedical: cleaning water pollution and PFAS

Beyond medicine, there are environmental applications for soft nanorobots such as cleaning toxins and “forever chemicals” like PFAS from water, removing pharmaceutical residues from hospital wastewater and cleaning oil spills. ( For more on IEC Standards relating to PFAS read this e-tech article.)

“Whenever nature evolves locomotion at small scales, it’s solving a transport problem. That principle can inspire solutions in medicine and environmental cleanup alike,” Nelson says. Researchers in the Czech Republic have developed nanobots 200 nm wide that remove 65,2% of arsenic from contaminated water in just 100 minutes. They work like tiny janitors with polymer hands, grabbing toxic molecules while powered by magnetic fields.

The invention could provide a sustainable and affordable way of cleaning up contaminated water in treatment plants, according to Martin Pumera at the University of Chemistry and Technology in Prague. The task now is to scale up and develop nanorobots to target different chemicals or pollutants. 

Medicine is an appropriately conservative field. Any new device must be at least as safe and effective as the current standard of care. Regulatory agencies require evidence that risks are minimized. To that extent, development in nano-microrobotic agents in medicine will be incremental, except when targeting diseases for which few other options for treatment are available. In treating glioblastoma, which has an extremely low survival rate,  a wider approach may be justified