3D printing has generated huge interest in recent years. The most well-known uses are in manufacturing, but over the last fifteen years, 3D printing has slowly expanded into the healthcare industry. 3D printing has already been used to produce medical devices and instrumentation, but it’s uses can expand further to personalized medicine through customized drug dosing, testing on patient-specific tissues, and even printing of tissues and organs.
What Is 3D Printing?
3D printing is a form of additive manufacturing, in which a three-dimensional object is built up from successive layers of raw material based on a digital model. Benefits of this approach include enhanced efficiency and flexibility. As compared to traditional processes, 3D printing wastes less raw materials and requires less manufacturing steps. Designers can easily make changes to 3D printed products without additional equipment or tools. The decreased cost of commercial 3D printers will also enable distributed manufacturing for at- or near-home printing of consumable products, dramatically restructuring the global supply chain.
3D Printed Medical Devices
By creating very complex internal structures, 3D printers can tailor medical devices to an individual’s anatomy. Patient-specific devices follow a template model that is matched using medical imaging to an individual’s unique anatomic features. Commercially available 3D printed medical devices include orthopedic or cranial implants (e.g., hip joints or cranial plates), surgical instruments (e.g., guides to assist with proper surgical placement of a device), dental restorations (e.g., crowns), and external prosthetics (e.g., hands). Dental implants have been particularly successful, with an estimated 50,000 custom-fit Invisalign braces printed every day.
The FDA regulates 3D printed medical devices through the same pathways as traditional medical devices. Currently, submissions for new 3D printed medical devices are evaluated for safety and effectiveness. Medical-grade PEEK plastic, used to make Spinal Elements’ Firefly surgical guides and Stryker’s Tritanium metal lumbar cages, achieved FDA approval in 2016, and many other 3D printing applications have now received 510(k) clearance.
One promising example for patient-specific devices comes from Spanish 3D printing startup Exovite, who uses a 3D scanner to precisely model a patient’s limb and then 3D print a personalized splint in just 30 seconds. The system includes a rehabilitation module, which stimulates the muscles below the cast with electric signals to speed up recovery and prevent muscle atrophy.
Healthcare providers are also exploring the implications of 3D printing. US doctors can use a government-sponsored 3D-printing repository to share tool designs for surgeries and treatments. And, earlier this year, the Ottawa Hospital started Canada’s first medical 3D printing program, which will seek to improve surgical planning and make 3D printed prosthetic limbs more accessible.
Finally, 3D printing can be used to create medical devices and supplies in areas that have limited access to healthcare. African organization ReFab Dar is recycling waste and turning it into 3D printable plastic filaments, and is running a design competition for 3D printed medical tools to create vital medical supplies in developing countries.
3D Printing of Drugs
Pharmaceutical companies are also embracing 3D printing, which will enable unique dosage forms, complex drug release profiles, and personalized drug dosing. In August 2015, Spritam (Levetiracetam) epilepsy medication became the first 3D printed pill to obtain FDA approval. It was developed by US-based Aprecia Pharmaceuticals, who gained the exclusive rights in 2007 to a computer-aided 3D printing technology developed at MIT for pharmaceutical purposes. Aprecia produces Spritam by sandwiching a powdered form of the drug between liquid materials and bonding them at a microscopic level. Due to their extremely porous nature, these high-dose drugs dissolve rapidly on contact with liquids, making them very effective for use in patients who experience sudden seizures.
3D Printing Can Control Drug Release
3D printing could be used to create many more unique dosage forms. In addition, by modifying a pill’s surface area by printing complex shapes, drug manufacturers could control both the strength of a released dose as well as its timing. 3D printing would enable personalized drugs that facilitate targeted and controlled drug release, giving more control over how and when a specific treatment is released into the body. Another route involves 3D printing pills with inner geometries, for example, where one drug forms the outer shell of a tablet and another fills the inside. Printing pills with a complex layered structure would allow us to create a combination of drugs to treat multiple ailments within a single pill.
Finally, 3D printed medications could aid in treatments for patients who respond to the same drugs in different ways. A healthcare provider could use an individual’s information including age, race, gender, and medical history, to customize their treatment according to the optimal dosage.
Eventually, improvements in design and operational efficiency will enable deployment of 3D printers at locations that are convenient for patients, such as hospitals and pharmacies. The ability to manufacture prescriptions on-site would reduce inventory needs and potentially save patients a considerable amount of time.
3D Printing of Tissues and Organs
The production of 3D printed organs sounds straight out of science fiction, yet experts suggest that we are less than two decades away from a fully functioning 3D printed heart. Scientists are already researching 3D printed bones, as well as tracheas, ears, kidneys, skin, and so on. These technologies will address a major need for donor organs. But in the near-term, we are much closer to seeing small-scale applications of 3D printed tissue in humans. Scientists have successfully implanted 3D printed biological matter into animals, and a number of companies are working on applying this technology to human tissues.
Bioprinting startup BioBots is currently working to deploy small, low-cost desktop 3D printers to print living cells. Harvard researchers have already 3D printed human heart tissue on a chip with integrated sensors. And, San Diego-based 3D bioprinting startup Organovo printed the first human liver-on-a-chip in 2014, and are now working to use their proprietary technology to build living human tissues that function like native tissues.
Such breakthroughs will allow us to study how a specific patient’s tissues may respond to drugs and toxic compounds with an unprecedented level of throughput. This tissue-on-a-chip technology could let us replicate a patient’s specific genetic disorder in the lab so that the properties of a disease or of an individual’s cells can be matched to develop customized testing and treatment.
Barriers to Implementation
The FDA has issued guidance for 3D printing in medical applications for medical devices, biologics, and drugs, and is working with companies to better understand 3D printing technology and to improve its guidelines to better serve businesses and individuals using 3D printing for medical purposes. However, some experts believe that 3D printed drugs will eventually require a complete reassessment of classification systems, and regulatory authorities may need to establish new guidelines for the approval of mass-marketed 3D printed drug products.
When manufacturing can move closer to the end user, liabilities will also become less clear. Pharmaceutical companies will have to ensure adherence to their recipes and to regulatory norms, with foolproof processes that reduce the chances of human error. In addition, there is some concern about tampering with 3D printing methodologies, including the possibility of hacking machines to produce counterfeit medications or to mask illegal drugs as legitimate compounds.
A final barrier to consider is the massive level of investment needed to develop completely novel treatments using 3D printing. The concept of printing drugs is often simplified in the media. However, there is a significant amount of money and time that is invested in an actual large-scale implementation.
Outlook and Opportunities
Compared to other industries, the impact of 3D printing technologies in healthcare has a lot of untapped potential. It is estimated that healthcare accounts for less than 2% of all investments made into the $700 million 3D printing industry. However, this number is expected to grow to 21 percent over the next 10 years, with market research firm Markets and Markets projecting that the use of 3D printing applications within healthcare will have a value of $2.1 billion by 2020.
3D printing could provide the framework necessary to make personalized medicine an essential part of tomorrow’s healthcare industry. Devices and implants tailored to the individual patient are already becoming commonplace, and they will be followed by single, easy-to-swallow pills designed to release a customized drug cocktail at defined intervals throughout the day. 3D printed tissues will accelerate the pace of pharmaceutical research, and within a few decades, 3D printed organs for transplant could make the need for organ donors obsolete. Research and development of 3D printing applications for healthcare is continuing at a rapid pace. Stay tuned for future updates.
