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We’ve been hearing about nanotechnology for a long time in both science fiction and in the media, but not much has come of it so far. However, a new wave of nanotech-based therapies are on the horizon, and are ready to change the world of medicine.
Nanotechnology, a technological concept first proposed by Richard Feynman in his 1959 lecture, “There’s Plenty of Room at the Bottom”, was popularized by Erik Drexler in 1986 via his book “The Engines of Creation.” The book outlined the possibility of self-replicating, molecular-scale machines capable of doing… pretty much anything.
The premise has inspired many science fiction works, including Michael Crichton’s “Prey” and Neil Stephenson’s excellent “The Diamond Age.” The potential of nanotechnology took a long time to show it’s face, but it is finally starting to arrive in the form of sophisticated medical interventions that will profoundly change the nature of healthcare in the near future.
Nanotechnology and Medicine
The potential for nanotechnology, in the full Drexlerian sense, is unprecedented. True universal assemblers, if we can figure out how to build them, will usher in a profound shift in the human condition. Of course, there’s a long way to go. In a lot of ways, we aren’t even close. In other ways, progress has been continuing in some surprising ways — and useful ones.
Moore’s Law continuously drives advances in nanotechnology – we can now manufacture transistors that literally exist on the nano-scale, with diameters of hundreds of atoms.
Likewise in medicine, one of the biggest issues is our inability to correctly target interventions. In psychoactive medicine and clinical psychology for example, what doctors really want to do is stimulate some brain regions and suppress others to selectively solve whatever problem the patient has. It’s a mere accident of history that the best way to do that right now is to administer medications that incidentally, in all the myriad of ways they change the brain and body, happen to have some of those desired effects.
If surgeons could put wires into peoples’ brains and selectively stimulate specific regions in a safe way, the mental health field could avoid the side effects of traditional psychoactive drugs. The basic technique has already been shown to work in depression, according to an article in Neuron summarizing a number of different clinical trials.
Think about cancer as well – what doctors really want, in oncology, is to kill tumor cells. It’s unfortunate that one of the best tools for killing tumor cells is chemotherapy, which has the unfortunate side effect of also killing regular cells. This also makes patients very sick.
Nanotechnology offers a way to direct interventions in the human body, potentially on a level of individual cells, using smart operating elements that are so small that they do not physically interfere with normal body function. Fine fingers do less damage, and machines smaller than the finest capillary in the body can go everywhere that blood goes.
If they can be made smart enough, such nanomedical devices can judiciously choose where and how to intervene. Obviously, more will be possible when engineers can build robots that have more sophisticated behaviors (like the ability to move under their own power), but even relatively primitive nanomachines of today have a lot of value.
Nanotechnology and Cancer
Custom strands of DNA are constructed such that they will fold into arbitrary shapes and can have proteins and enzymes bonded onto them, allowing them to behave in intelligent ways and respond to changing situations in the human body. Daniel Levner, a bioengineer at Harvard, believes that this behavior is very powerful.
DNA nanorobots could potentially carry out complex programs that could one day be used to diagnose or treat diseases with unprecedented sophistication.
These machines can be used to build cages that can open or shut in response to chemical cues — for example, releasing chemotherapy only when they bump into protein markers specifically associated with tumor tissue.
This will allow the application of directed chemotherapy, while minimizing or eliminating side effects. This will also allow the deployment of chemotherapies which are more effective than existing therapies, but can’t currently be used due to the seriousness of the side effects.
A similar but different approach is to use tiny nanoparticles made of silica and gold that bind to tumor tissue, and saturate the tumor. Then, near-infrared lasers can be applied, which don’t interact much with the human tissue, but do cause the gold nanoparticles to heat up.
This process allows specific areas of tissue (those filled with nanoparticles and in the path of the laser) to be incinerated. By tuning both the lasers and the particle distribution, doctors can destroy cancer tissue very selectively. The dead tissue can be surgically removed or cleaned up by the immune system itself, depending on scale of the disease. A variation of the procedure is to use hollow gold shells that release a payload of chemotherapy when heated, allowing the use of lasers to further refine where drugs are deployed (if tumor marker proteins aren’t sufficiently specific).
Nanotechnology and Diagnostics
Another area in which nanotechnology has the potential to revolutionize the medical field is in medical data collection. With nanotechnology, it is possible to distribute nano-scale diagnostic devices throughout the body that detect chemical changes as they happen. This may allow closer real-time tracking of a patient’s health and status in ways that aren’t otherwise possible.
Outside the body, nanotechnology can also be used to speed up gene sequencing and chemical analysis by using quantum dots attached to either partial DNA sequences, or proteins that bond to other materials doctors are interested in. Then, you can just look at the distribution of glowing elements to see what was present in the sample.
This could potentially make it faster, cheaper, and more reliable to do certain kinds of testing outside the body – you could build tests that take a small tissue sample and sequence it for pieces of the HIV genome, detecting infections earlier and more reliably. Researchers at Stanford have used this technique to look for damaged genes common in certain cancers, as a way to screen tumor tissue faster:
Because qdots can track the presence of multiple molecules over an extended period of time, researchers aim to use them to generate a kind of optical barcode reflecting the levels of various tumor markers. The barcode could indicate tumor type and stage.
In the long run, if nanotechnology developers can continue to miniaturize the parts (or borrow techniques from microchip fabrication), they could build simple microscopic cameras, smaller than the diameter of a capillary (10 microns, or about 100,000 atoms across). These cameras could map the entire body, phoning home the results.
All that data, synthesized together, could provide a complete map of most of the tissue in the human body, from the perspective of its capillaries, showing an entire human body in a level of detail that’s impossible with X-ray or MRI. One proposal for building something like this is the so-called “Vascular Cartographic Scanning Nanodevice”, being developed by Frank Boehm, the author of ‘Nanomedical Device and System Design.’ Boehm believes:
Nano-medical diagnostics and therapeutics operate at cellular and molecular levels, precisely where many disease processes find their genesis […] [N]anomedicine has the potential for diagnosing and treating many conditions preemptively, before they have the opportunity to proliferate.[…] [I]t is conceivable that they will be imbued with capacities for the highly accurate diagnoses and meticulous and thorough eradication of virtually any disease state, pathogenic or toxic threat.
Nanotechnology and Neuroscience
Nanotechnology also has the potential to change how doctors treat brain disorders. On the data-collection side of things, it may be possible to use nano-scale diamond particles, which light up in response to the brain’s electrical activity, to convert brain activity into frequencies of light that could escape the skull and be registered by external sensors.
This would allow researchers to study the brain in much greater detail. Being able to see exact patterns of brain activity would be helpful for ferreting out the dynamics of seizures and mental illness in individual brains, allowing for targeted interventions to solve the problem.
On the flip side, it may be possible to use carbon nanotubes to carry signals to and from individual neurons. Right now, the technology is being applied by Italian researchers to carrying electrical activity across dead brain tissue left by strokes or infections, but it could also be used to make electrode grids that are much finer and more bio-compatible than existing technology, allowing for more sophisticated implants while doing less damage to the original tissue.
This could, in principle, operate at a much higher resolution and across a broader scope than traditional implanted electrodes, allowing new kinds of brain implants and brain stimulating devices. Even with the relatively crude electrode implantation available today, the effects of brain stimulation are significant:
Alternately, it’s possible to use the same techniques used for nano-delivering chemotherapy to deliver other chemicals, like neurotransmitters and psychiatric drugs to specific brain regions with much more precision (including delivering drugs inside individual cells). Along with better neural pacemakers, this could also extend to a much broader range of therapies, including treatment for depression, anxiety, and even personality disorders.
This sort of therapy could also be used to create tighter interfaces with prosthetic devices and provide more communication options to ‘locked-in’ patients.
This kind of precisely targeted technology might radically change the way that neurological medicine is practiced. It could lead to psychiatric medicine that is data-driven and relies on direct intervention that is far more effective, and far more existentially upsetting (imagine the first computer virus that can infect mood-regulation brain implants).
Nanotechnology, as it advances, will have a profound impact on the human condition, allowing us to repair cellular damage and treat a variety of human afflictions in new and better ways, but it also brings with it a need for greater understanding of the body systems that we’re tampering with, as well as an appreciation of the ethics that go along with that.
What is your take on nanotechnology in medicine? Do you feel it’s the new frontier for medical science, or is it doomed to fail from the start? Share your thoughts in the comments section below.
Image credits: Nanobots Via Shutterstock, “DNA can act as velcro for nanoparticles,”, by Argonne National Labs, “B0006421 Breast Cancer Cells“, by Amy Dame, “Quantum dots“, by Argonne National Labs, “autism neuro-imaging study“, by Ian Ruotsala, “life-hand 2“, by Università Campus Bio-Medico di Roma