It is already possible to design and computationally model nanomedical devices, complex molecular machines intended to operate in large numbers in our tissues for extended periods of time, even if it is not yet possible to manufacture and use them in the large numbers needed. This design and modeling has been going on for quite some time in some portions of the research community, in fact. You might recall the respirocyte as an early design, a device to multiply the oxygen carrying capacity of blood a hundredfold or more. This is only one of a growing stable of designs, many of which are intended to carry out repair of the damage of aging since there has long been an overlap between advocates for life extension and advocates for molecular nanotechnology. This is groundwork for the medical technology of the 2030s and beyond, as constructing and using such machines in large enough numbers to matter will require, at the very least, precision molecular manufacturing - which is the large hurdle - and a range of incremental advances in wireless command and control systems.
Futurists have long speculated that nanotechnology - the engineering of materials and devices at the molecular scale - will revolutionise 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.
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). The acquired spatial data would then enable physicians and surgeons to "fly through" the entire circulatory system using a joystick and computer display. 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.
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." 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 localised 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.
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. 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.