Futurists have long speculated that nanotechnology — the engineering of materials and devices at the molecular scale — will revolutionize virtually every field it touches, medicine being no exception. Here's what to expect when you have fleets of molecule-sized robots coursing through your veins.
To learn more about the potential for medical nanotech, I contacted Frank Boehm, author of the recently released book, Nanomedical Device and Systems Design: Challenges, Possibilities, Visions.
Boehm has been involved with nanotechnology and especially nanomedicine since 1996, and has been developing numerous concepts and designs for advanced nanomedical tools. His ultimate goal is to develop and transform these concepts into real world applications for global benefit.
During our conversation, we spoke about current nanomedical efforts and those still yet to come — including molecule-sized robots and capsules that will detect and treat diseases. But we also talked about the potential for nanotechnology to radically alter human capacities, such as giving us infrared and night vision, extended lifespans, and the ability to live and work in outer space and planetary colonies. We also discussed the downsides and what we'll have to do to protect our nano-infused selves from hackers and viruses.
io9: Nanomedicine is often used to describe two different things, nanotechnology and biomimetics. What's the difference?
Frank Boehm: Nanotechnology is a powerful and fundamental enabling technology that involves the ability to manipulate matter at the nanometer (nm) scale (1 nm being equivalent to one billionth of a meter, or a thousandth of a thousandth of the thin side of a dime), and it's commonly in the range of 1 to 100 nm.
The ability to work at this scale will allow for the fabrication of unique materials and devices with improved and novel properties, such as enhanced water repellency (superhydrophobicity), or the increased performance of chemical reactions (catalysis) due to dramatically increased active surface areas.
Biomimetics, on the other hand, involves the development of unique artificial surfaces, devices or systems, through the inspiration and emulation of naturally occurring processes or systems. For instance, superhydrophobicity was inspired by the natural waterproofing system of the lotus plant (Nelumbo nucifera) and is known as the Lotus Effect.
But it's worth noting that current (first generation) nanomedical "devices" are still quite rudimentary and passive as they're simply carried through the body by circulation. They consist of special types of nanomaterials such as nanoparticles, solid or hollow metallic or polymer nanoshells, various sorts of nanotubes, and hollow nanospheres (liposomes), which are made up of natural lipid molecules. Similar lipid molecules make up the membranes of our cells.
These nanomaterials may, however, be endowed with a certain level of control, and can reach specific destinations within the body when they are first connected to ("decorated" with) special types of molecules (targeting agents), which have strong attractions (affinities) for proteins that exist on the outer surfaces of particular diseased cells or tissues.
Some of the daunting challenges facing developers will be to get these tiny molecular machines to navigate through the human body. For example, viscosity increases at these levels; when traversing the circulatory system, it will be as though they are forced to swim through molasses. Therefore, specialized propulsive mechanisms must be designed that will allow for meaningful movement.
But thankfully, we have examples in nature — things like bacterial flagella (long whip like structures that are attached to rotating biological motors), and cilia, which are 200-300 nm in diameter by 5-20 micron long hair-like structures that beat in unison with thousands of identical units. Hence, synthetic analogs of these nanoscale propulsive units might be designed and fabricated to transport nanomedical devices through the human body.
What's the current state-of-the-art when it comes to nanomedical devices?
One of the current state-of-the-art nanomedical devices involves gold nanoshells (100-200 nm in diameter) that consist of solid silica cores that are surrounded by thin gold "skins". Nanospectra Biosciences employs gold nanoshells for its "AuroLase Therapy", which are introduced into the patient intravenously and then used to rapidly convert near-infrared laser light (which is safe for the human body) into heat through a process known as surface plasmon resonance. When the gold nanoshells are targeted to and chemically attached with a cancerous tumor, for example, they may be activated with the laser light to the point that they will thermally destroy the tumor.
This non-drug therapy is called hyperthermia and has the advantage of being non-toxic with no unpleasant or harmful side effects, which can indeed be the case when patients are "flooded" with chemotherapeutic drugs. Additionally, it is very specific to diseased sites and inflicts minimal collateral damage to neighboring healthy cells and tissues. AuroLase Therapy is currently undergoing preliminary human clinical trials for head, neck and lung cancers. Hollow versions of gold nanoshells may also be filled with powerful drugs and utilized to precisely deliver them to tumors. In this case, near-infrared laser light causes the hollow nanoshell walls to rapidly heat up, deform, and then collapse, which subsequently releases the encapsulated drug payload.
Additionally, a rapidly evolving nanomedical technology against cancer, as well as other diseases, takes the form of magnetic nanoparticles, such as Superparamagnetic Iron Oxide Nanoparticles (SPIONs), which may be thermally activated in a similar way to gold nanoshells. When activated, the encased SPIONs melt the polymer wall within which they reside to release the drug payload. These nanoscale entities are FDA approved as medical imaging contrast agents and for other applications.
The liposomes mentioned above are also FDA approved for some drug delivery applications, and range in size of from 50 nm to several microns in diameter. They have advantages of being filled with a wide range of therapeutic agents, including antibiotics.
A variety of "smart theranostic" nanoparticles are under development as well, which may be targeted directly to diseased sites to serve multiple beneficial roles as diagnostic, drug delivery and therapeutic monitoring agents. These entities may be composed of such nanomaterials as iron oxide, a variety of biocompatible polymers, or quantum dots, which are semiconducting nanocrystals that can strongly emit light.
What kind of diagnostic potential does nanotechnology hold?
Let me tell you about one conceptual nanomedical diagnostic concept to give you an idea.
It's what I call the Vascular Cartographic Scanning Nanodevice (VCSN) — a sophisticated and autonomous one micron wide nanomedical device for imaging living organisms. I envisage that thousands of VCSN devices would work in massively parallel fashion to scan and image the entire human vasculature, down to the capillary level (3 microns).
Artistic representations of Vascular Cartographic Scanning Nanodevice (VCSN)
The acquired spatial data would then be transferred to a Pixel Matrix display, which would enable physicians and surgeons to "fly through" the entire circulatory system using a joystick and computer display. Other useful display formats might include holography and virtual reality. These ultrahigh resolution medical images would allow for the detailed inspection of every portion of the system to discover plaque deposits and to precisely determine arterial/venous wall thicknesses, and hence, whether the patient might be at risk for a potential aneurysm, particularly within the brain.
How about therapeutic applications? Like treating toxins and disease?
We could use these devices to significantly enhance the human immune system. I describe one such class of conceptual nanodevice, which I have dubbed the "sentinel."
Artistic representation of "sentinel" nanodevices
Once nanomedicine matures, the human immune system might be augmented with the capacity to rapidly identify and eradicate threats, like chemical toxins or pathogenic micoorganisms. Autonomous micron-scale "sentinel" class nanodevices, imbued with comprehensive data on all known toxins and pathogens, might continually "patrol" the human vasculature and lymphatic system for the presence of invasive species. They could also penetrate into tissues.
And if an unknown intrusive agent is discovered, a default protocol would be spontaneously launched to ensure their complete destruction via chemical, oxidative, hyperthermic, or highly localized nanomechanical disassembly.
These Sentinels could operate in conjunction with the innate human immune system, serving as exceptionally sensitive "first responders" to rapidly identify, engage, disable, and degrade all manner of foreign entities.
Nanomedical devices hold tremendous promise for human enhancement. Can you provide some examples?
Nanomedicine could augment practically all human systems and senses. This could include advanced nanomedical retinal implants that may initiate or restore sight in clinically blind individuals, someday giving them 20/20 full color vision. Human vision might be expanded to allow the perception of infrared or ultraviolet wavelengths, integrated night vision, or perhaps to certain extent, even telescopic or microscopic visual capabilities through precise lens augmentation and manipulation.
Generic cell repair nanodevices.
In terms of specific forms of potential human enhancement, particularly for cognitive augmentation, there will certainly be ethical, as well as moral concerns that we, as human beings, will be compelled to address.
Could nanotechnology be used to extend human lifespan?
Absolutely. For example, the extension of the human lifespan could be facilitated through the removal of a substance called lipofuscin from certain types of non-dividing cells, including the brain, heart, liver, kidneys and eyes. Lipofuscin is a metabolic end product that accumulates primarily within lysosomes (the garbage disposal organelles within cells). It's thought that when lipofuscin accumulates to certain levels, it begins to negatively impact cell function, which eventually manifests in many age related conditions. Aubrey de Grey et al. have proposed that soil bacterial enzymes might have the capacity for degrading lipofuscin. de Grey (Chairman and Chief Science Officer of the Methuselah Foundation and Editor-in-Chief of the high-impact journal Rejuvenation Research) proposes that humans might live as long as 1,000 years under the appropriate rejuvenative therapies.
Artistic rendering of a conceptual "Defuscin" nanomedical device.
I imagine a procedure in which dedicated "Defuscin" type nanodevices are deployed — they would enter cells and then the lysosomes to bind with and remove lipofuscin through an enzymatic or nanomechanical digest and discharge protocol (a fundamental concept that was originally proposed by Robert Freitas).
Nanomedical devices could also be used to help humans work and live in space.
Yeah, we're going to need nanotechnology if we're to negate the the deleterious effects of gamma radiation and microgravity.
One idea is a conceptual nanomedical devices that I call "osteolaminals" whose task it would be to systematically "top dress" the bones of astronauts, by applying multiple layers of bone building/reinforcing materials directly to bone surfaces.
No doubt, nanotech will serve as a perfect fit for space travel — they'll possess many of the attributes that align well with this noble and adventurous enterprise, albeit, one that is sometimes fraught with extreme risk.
Nanomedical technologies will be used to support future Moon and Mars colonies, posing a minimal burden on the tight spatial constraints that will most likely accompany early colonies, while offering an extensive range of highly specific diagnostics and therapeutics — and all paired with powerful AI in instances where unknown Lunar or Martian elements might cause a particular sickness or disease.
In which ways could nanomedical devices go wrong? Could they be hacked externally, or by the user itself?
Unfortunately, yes. But various default protocols would immediately kick in should any nanomedical device be damaged or malfunction in some way. Depending on the damage or malfunction, these might range from immediate transport to, and power down at, predetermined egress sites (e.g., elimination organs, sweat pores, hair follicle roots, or finger or toenail beds) to instantaneous shutdown, with subsequent retrieval and removal by accompanying nanodevices to appropriate egress sites.
Nanomedical software could also be infected or disabled by other classes of nanodevices or AI-controlled implants that reside within their own bodies. Disruptive code might also conceivably be unwittingly conveyed by other implanted patients who are within transmission range or surreptitiously transmitted wirelessly from external sources over great distances.
Consequently, it will be prudent — if not critical — to establish international standardized software protocols for the protection of nanomedical quantum computation devices and other nanocomputers to certify that they will be compatible when in operation within patients, and rendered "immune" to external online corruption.
When can we expect to see the nanomedical devices you describe in your book?
The emergence of intelligent and autonomous nanomedical devices may likely still be 10 to 30 years out, as their design will likely require the assistance of Artificial Intelligence (AI), and their fabrication will necessitate the development of sophisticated molecular manufacturing capabilities. Molecular manufacturing may potentially take the form of advanced 3D printers that use various species of atoms and molecules, rather than ink, to build up nanodevices layer by layer according to preprogrammed designs.