Almost half a century later, reality is approaching the once distant realms of science fiction with the advent of 3D printing. Three-dimensional or 3D printing is the construction of an object by printing sequential layers of material on top of one another. 3D printing presents a unique opportunity to reduce healthcare disparity by substantially reducing its cost, while increasing personalisation; a rapidly converging Venn diagram.
The rapid and prolific rise of 3D printing technology is offering a practical solution for the millions living without limbs. In the United States alone, there are an estimated 1.7 million amputees, with over 200,000 amputations performed each year. Prosthetic limbs cost upwards of $5,000, need to be replaced every few years, and have the same limited functionality that inflicted Captain Hook with his own namesake. However, 3D printing is lending it’s hand to the democratisation of prosthetics and will enable millions of people around the world, particularly those in war-torn countries, to own a personalised prosthetic limb for a fraction of the traditional cost. With a widening palette of printable materials, including lightweight and durable titanium, and the novel combination of multiple materials in 3D printing; future prosthetics will be more durable, comfortable, and seamless.
Research in cybernetics, the science of engineering mechanical systems which can communicate with living organisms, is leading to interesting developments in 3D printing. Why limit 3D printing to a poor imitation of the human body, when it could be used to improve our potential? 3D printed biodegradable scaffolds implanted in the human body, would allow tissue to grow in and around that scaffold, effectively kick-starting the growth of new bone. Joining biological tissue and functional electronics would create multi-dimensional bionic organs which possess enhanced sensory functions over their human counterparts. A proof-of-concept research project by scientists at Princeton University has resulted in a bionic ear infused with nanoparticles, created using 3D printing, that can hear radio frequencies far beyond the range of normal human capability. The merging of biological and electronic functionalities represents a seismic shift from today’s current status quo to not only replicating human ability, but enhancing it.
In the ultimate benevolent act of brotherly love, Ronald Herrick donated a kidney to his twin brother on December 23, 1954 in the first ever organ transplant operation. While organ donation is a relatively recent medical advancement, the notion of transferring an organ from one human to another will soon be outdated with the emergence of 3D printed organs. With a global waiting list of 119,000 people, the deadly game of musical chairs played by hopeful and desperate organ recipients will soon be rendered obsolete by 3D bioprinting living tissue. Organovo, an early stage research laboratory, has been experimenting with bioprinting functional human tissue, and has already successfully bioprinted miniature livers and kidneys. A team at the University of California, San Diego, successfully created a hexagonal structure made of liver and supporting cells that has access to blood supply, functions just as a real liver would, and can be printed in seconds, making organ rejection a bitter distant memory.
The 3D bioprinting of artificial human organs will usher in a brave new era in the development of pioneering and innovative drugs, minus the current necessary evil of animal testing or human clinical trials. Pharmaceutical companies will be able to safely test new drug formulas on 3D printed human organs, leading to more accurate results, at an earlier stage in the development lifecycle. San Francisco based startup, Aether, recently partnered with the Cancer Nanotechnology Excellence at Stanford University to 3D print tissue cells that will serve as test models for new and experimental drugs, a bold first step towards ending the practice of animal testing completely.
Into another dimension
Flexing its synthetic muscles, four-dimensional printing is emerging from the sidelines to claim its rightful place, centre-stage. Inspired by living organisms’ ability to react and adapt to their environment, 4D printing incorporates the added element of time. When exposed to an external trigger, be it pressure, moisture, temperature, electricity, heat or light; 4D printed dynamic composite structures can change their form on command, and even return to their original dimensions or dissolve into the human blood stream at a later date. This sequel to 3D printing promises the ability to use the body temperature as a trigger, where 4D drug delivery vehicles are designed to only release potent payload at the first sign of a fever. While still in its infancy, researchers at the University of Michigan have printed airway splints which are engineered to grow at the same pace as the patient. Rather than replacing the splints as the patient outgrew them, doctors implanted into three patients 4D printed airway splints that expanded over time. This approach could also be applied to the treatment of other infant conditions where there is expected to be a “significant increase in either organ or anatomic structural change”.
While the disadvantages to 3D printing technology are few and far between, it is worth reflecting on our own moral Achilles heel, and questioning the true value of own fragility when new organs could be printed at will. Or, would we “live the full life of the mind, exhilarated by new ideas, intoxicated by the romance of the unusual.” It’s up to us to decide…
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