Abstract

This article examines how revolutions in three-dimensional (3D) printing technology have impacted the United States medical field. The applications of this technology include tissue and organ fabrication, customized prosthetics, implants, operating room tools, and anatomical models. 3D printing technology has also impacted pharmaceutical advancements regarding medication creation, delivery, and discovery. This article analyzes a number of benefits and costs that arise across the aforementioned categories. Lastly, future trends and recommendations are offered that can significantly enhance the U.S. medical field.

Tissue and Organ Fabrication

3D printing can be defined as a “...manufacturing method in which objects are made by fusing or depositing materials—such as plastic, metal, ceramics, powders, liquids, or even living cells—in layers to produce a 3D object” (Ventola). This technology can radically reshape ineffective tissue and organ harvesting processes that currently plague the medical field. Over 150,000 patients in the U.S. are awaiting an organ, yet only approximately 18% will receive one (Cui et al.). Unfortunately, this could result in the untimely deaths of over 25 of these patients per day as they wait for an organ (Cui et al.). Based on such disturbing facts, it is clear that an effective intervention is warranted. In the current system, treatment for organ failure tends to heavily rely upon organ transplants from living or deceased donors. Yet this is problematic because there is a chronic nationwide shortage of human organs available for transplant (Schubert et al.). An additional problem with the current system is that organ transplantation involves the often problematic issue of locating a donor who is a biological match under dire time constraints. 3D printing can alleviate many of the aforementioned concerns by using cells taken from the organ transplant patient’s own body to build a replacement organ. “This would minimize the risk of tissue rejection, as well as the need to take lifelong immunosuppressants” (Schubert et al.). 

3D printing provides a contrast to a traditional model which isolates stem cells from small tissue samples, mixes them with growth factors, multiplies them in a laboratory, and seeds them onto scaffolds that direct cell proliferation and differentiation into functioning tissues (Bartlett et al.). 3D printing can offer extra benefits beyond this traditional method. Some examples of these advantages include highly precise cell placement as well as a high digital control of speed, resolution, cell concentration, drop volume, and diameter of printed cells (Cui et al.). Although tissue printing is still new, researchers have been able to use this technique to create a knee meniscus, heart valve, spinal disk, other types of cartilage and bone, and an artificial ear (Mertz et al). 

Creation of Customized Prosthetics, Implants, Operating Room Tools, and Anatomical Models

3D printing provides an element of personalization in numerous U.S. healthcare settings, such as the operating room (Mertz). This idea has been extended to implants and prosthetics through translations of X-rays, MRIs, and CT scans that are converted to .stl files – a format often used for 3D printing (Klein et al.). This approach has been used successfully in U.S. healthcare settings to create simple and complex prosthetics and implants quickly. In fact, some of these items can even be created in less than 24 hours under certain circumstances (Banks et al.). This time component is particularly relevant for surgeons and surgery patients. Increased efficiency can help to ensure a higher rate of positive surgical outcomes. 

A widespread problem in the field of orthopedics in the U.S. is that standard implants may not be adequate for some patients, especially ones with complicated cases (Banks et al.). Formerly, surgeons needed to perform bone graft surgeries or use scalpels to shave and refine metal implants to cohere with each patient’s specificifications. 3D printing can revolutionize this inefficient method. This is because it can quickly produce customized implants or prosthetics for such uncommon patients. An example of mainstream customized 3D printing in a related field is Invisalign. Invisalign is a commercial use of 3D printing that manufactures braces and retainers tailored specifically to each patient, “...with 50,000 printed every day” (Lipson). 

3D printed implants in the U.S. are currently gravitating toward a variety of metals and polymers, and even more recently there have been some printed with live cells (Lipson). An example of this trend is evident in the recent production of 3D printed, anatomically correct prosthetic ears. These ears are “...capable of detecting electromagnetic frequencies [and have] been fabricated using silicon, chondrocytes, and silver nanoparticles” (Gross et al). This technology can even be used for personalization since “...99% of hearing aids that fit into the ear are custom-made using 3D printing…” (Banks et al.). It is especially important to apply such technology to this field because ear shape can vary widely from person to person. 

3D printed models have also been used in a great number of cases throughout the U.S. to acquire an in-depth understanding of patient anatomy before a medical procedure (Gross et al.). Having a physical model of a patient’s anatomy is preferable to relying only on MRIs and CT scans, which are merely viewed in two dimensions. Three dimensional models can be considered far more accurate replicas of patients’ organs. This 3D printing-based approach offers medical professionals better planning methods and can improve patient outcomes in the form of safer organ transfer rates. 3D printed models can even have advantages beyond surgical planning. “Recently, a polypeptide chain model was 3D printed in such a way that it could fold into secondary structures because of the inclusion of bond rotational barriers and degrees of freedom considerations” (Gross et al.). Similar 3D models can be used to enable medical professionals and students to better understand complex types of biological and biochemical structures.

Pharmaceutical Research Regarding Medication Creation, Delivery, and Discovery

3D printing has the potential to dramatically revolutionize conventional prescription drug fabrication processes across the nation. “The advantages of 3D printing include precise control of droplet size and dose, high reproducibility, and the ability to produce dosage forms with complex drug-release profiles” (Ursan et al.). To date, 3D printers have been used to produce many new types of dosage forms. These methods include microcapsules, hyaluronan-based synthetic extracellular matrices, antibiotic printed micropatterns, mesoporous bioactive glass scaffolds, nanosuspensions, and multilayered drug delivery devices (Ursan et al.). Furthermore, the creation of medications with complex drug-release profiles is another noteworthy application of 3D printing processes. 3D printers can print a binder onto a matrix powder bed in layers typically 200 micrometers thick, creating a barrier between the active ingredients to facilitate controlled drug release (Gross et al.).

In light of these positive strides thus far, researchers project that 3D printing technologies will ultimately be fully customizable for patients according to their specific needs. U.S. pharmacists could analyze a patient’s pharmacogenetic profile, as well as other characteristics such as age, race, or gender, to determine an optimal medication dose (Ursan et al.). In turn, pharmacists can then 3D print and dispense the personalized medication. If necessary, the dose could be easily adjusted further through such technology based on clinical response (Ursan et al.). In addition, these types of personalized medicines may occur in entirely new formulations. For example, these novel manifestations can include pills with multiple active ingredients, either as a single blend or as complex multilayer or multireservoir forms (Khaled et al.). This means that patients who have multiple chronic diseases could have their medications printed in one multidose form that is fabricated at the point of care (Khaled et al.). It is also possible that providing patients with a highly personalized dose of multiple medications within a single tablet can improve their prescription drug compliance. 

Low Economic Burden

In general, “...the cost to custom-print a 3D object is minimal, with the first item being as inexpensive as the last” (Schubert et al.). This is especially advantageous for companies, researchers, or other members of the U.S. medical field with limited budgets. In addition, the generally low production cost of 3D printing can benefit companies with low volumes or that produce specific products that contain a high level of intricacy (Mertz). In fact, these characteristics of 3D printing can even reduce the costs of orthopedic and maxillofacial surgery. “Seven studies using 3D printed anatomic models in surgical care demonstrated a mean 62 minutes ($3720/case saved from reduced time) of time saved, and 25 studies of 3D printed surgical guides demonstrated a mean 23 minutes time saved ($1488/case saved from reduced time)” (Ballard et al.). These findings suggest that 3D printing can significantly decrease annual fixed healthcare costs. This is particularly true with respect to surgical procedure expenditures. “Based on the literature-based financial analyses, medical 3D printing appears to reduce operating room costs secondary to shortening procedure times” (Ballard et al.).

Another way in which 3D printing can reduce U.S. healthcare costs relates to cell cultivation. 3D printing advances have empowered researchers to seamlessly use stem cells in tandem with relevant growth factors. This can lead to more efficient and inexpensive tissue engineering strategies. “To achieve these results cost-effectively, researchers have converted a 3D printer into an open source 3D bioprinter and produced a customized bioink based on accessible alginate/gelatin precursors” (Ioannidis et al.). There are many facets of this bioprinter that contribute to its efficacy. One example is bioprinter resolution. This pertains to the deposited material in the x- and y-axes, while dimensionality defines the structural resolution of printed constructs (Lee et al.). Accurate line width functionality is also an invaluable component of bioprinter cost-savings mechanisms. This is because line width can ensure shape fidelity of printed products (Gillispie et al.). In addition, bioprinter spreading ratio utility is important because it prevents product output imperfections that might ordinarily arise due to the prevalence of surface tension in traditional manufacturing processes (Schwab et al.). 

With consumer demand growing for 3D printers, there are now numerous models that are easy to access by the U.S. public, inexpensive, and can function on desktop computers. These printers are typically used to create moderately priced or free open-software related to healthcare products. This type of creation leverages fused deposition modeling (FDM), which is one of the most inexpensive methods of printing. “User stories from investigators at the National Institutes of Health and the biomedical research community demonstrate the power of 3D printing to save valuable time and funding” (Coakley and Hurt). Even though adapting 3D printing in the biosciences may appear to be gradual, its long-lasting potential for consumer creation of healthcare-related products is promising.

Collaborative-Based Accuracy and Efficiency

3D printing can also foster collaboration between members of the U.S. scientific community. “The nature of 3D printing data files…offers an unprecedented opportunity for sharing among researchers” (Gross et al.). Rather than trying to manually reproduce parameters that are described in scientific journals, researchers can access downloadable “.stl” files that are available in databases (Gross et al.). These databases allow computer users to seamlessly draw upon the work of their peers in this field for instant use. In addition, these facets of 3D printing allow collaborators to expand upon the work of others and enhance it. Thereafter, the final, improved product can be readily available for others to download. “Toward this end, the National Institutes of Health established the 3D Print Exchange (3dprint.nih.gov) in 2014 to promote open-source sharing of 3D print files for medical and anatomical models, custom labware, and replicas of proteins, viruses, and bacteria” (National Institutes of Health). 

Within the context of 3D printing technology, efficient medication and prosthetics production is currently estimated at a few hours (Mertz). This time frame can vary based on the item(s) being produced. Overall, the U.S. time-to-production window of 3D printing makes medication and prosthetics production technology much faster than traditional methods. Fortunately, an increase in production speed is not necessarily at the expense of quality. Beyond enhanced time-to-production estimates, other qualities, such as the resolution, accuracy, reliability, and repeatability of 3D printing technologies, are also in the process of improving (Banks).

Challenges

Despite all of the potential advantages that 3D printing can offer Americans, there are a number of critical downsides to this technology when it is not used ethically. For instance, it could be “...abused to make illegal, counterfeit, lower-quality medical devices or prescriptions” (Hoy). These uses of such technology can potentially jeopardize human health. In addition, there are a number of legal issues that arise from the use of 3D printing for healthcare purposes. In light of this, regulatory protocols are required to curtail the aforementioned negative impacts of 3D printing (Kirillova et al.). This drawback of 3D printing includes the fact that some prints “...have been subject to patent, industrial design, copyright, and trademark law for decades” (Hoy) and may not be easily replicable due to legal constraints. In fact, that is a major reason why the U.S. Food and Drug Administration has created a group that judges technical and regulatory concerns for 3D printing (Beck et al.).

Another dilemma pertains to the ethics of printing 3D organs. Although this technology may be able to address part of the U.S.’s organ transplantation shortage, it can raise questions about being used for human enhancement as opposed to technological immortality. Technological immortality is defined in terms of people printing out new organs and replacing their old ones for a motive that might be less pressing than imminent health concerns (Bushev). Furthermore, cell harvesting can present the bioprinting industry with a number of ethical issues to consider. “The type of cells used plays a key role in determining the characteristics of the bioprinted tissue. In the case of allogeneic cell transplantation, we face classical ethical problems associated with donation” (Kirillova et al.). These issues include, but are not limited to, donor confidentiality, informed donor consent, potentially invasive cell production procedures, and donor cell ownership. 

In the U.S., one of the major ethical issues surrounding 3D printing is with respect to the use of stem cells. By and large, stem cells are considered to be the foundational elements of human tissue and organ printing. “The main source of these cells are embryos or fetuses, so the problem of obtaining ESC [embryonic stem cells] is at the intersection of bioethical problems of determining the moral status of an embryo, legal pregnancy termination, and human participation in the experiments (Kirillova et al.). Ethicists have voiced that obtaining stem cells from donors who have been forced or pressured (without informed consent) should be taken into consideration before undertaking related 3D printing processes. In addition, there are ethical and sometimes legal barriers in the U.S. when implementing the printing of tissues or organs for the purposes of commercialization. 

One potential remedy to such dilemmas can be found in reprogramming differentiated cells and producing induced pluripotent stem cells (IPSCs) to create bioink for 3D printing. “IPSCs can be purposefully differentiated into any specific adult body cell types, ranging from skin cells to cardiac cells and neurons” (Kirillova et al.). Unfortunately, even the process of creating bioink from IPSCs may pose its own share of ethical problems. For example, “...the risk of tumorigenicity is a major problem when using IPSC…To provide safety of IPSC-based therapies, genetic testing of stem cell lines potentially suitable for clinical application has to be performed” (Kirillova et al.). Yet even when implementing these safeguards, the process may not be foolproof. These safeguards raise additional ethical and legal issues related to personal genetic information collection, storage, and use (Kirillova et al.). For example, the exchange of data for research purposes heightens the number of individuals who can access personal genomic data. As a result, this can increase the likelihood of data leakage and its potential to be used for illegal purposes. 

Although the U.S. government may offer recommendations for data-sharing related to 3D printing, many key terms regarding this process remain largely undefined. “Requirements for obtaining consent from a donor for participation in research, as well as requirements for the processing and transfer of genetic information as a special category of personal data, are not defined in [many] existing legislation” (Kirillova et al.). In addition, widespread regulation of biological material circulation does not seem to exist. This is especially true when biological material is obtained from donors in order to undertake scientific research. In such instances, donors are not necessarily provided with safeguards that their rights will be protected. This may be primarily because there is a general lack of mandatory, government-imposed stipulations for such safeguards.

U.S. research and bioethics committees have also inquired into ethical problems raised by 3D printing-related issues such as informed consent and the principle of confidentiality. “The principle of confidentiality is closely related to the notion of ‘medical secrecy’ and implies that the circumstances of treatment and the patient’s characteristics are kept confidential with respect to the patient’s life” (Kirillova et al.). Confidentiality can assist medical professionals in the process of building trust with their patients and help them seek more consistent care. It originates from basic human rights concepts and is widely adopted. “For example, the Nuremberg Code provides for absolute voluntary consent for human participation in medical trials including knowledge of the nature, duration, and purpose of the experiment, its methods, and associated risks” (Kirillova et al.). A more contemporary adaptation of the Nuremberg Code is evident through the Convention on Human Rights and Biomedicine. According to this source, “...medical intervention can be performed only after the person gives his/her voluntary written consent based on the information received on the purpose and nature of the intervention, as well as its consequences and risk” (Kirillova et al.). One potential issue arises when medical professionals attempt to obtain informed consent in situations when patients are unable to express it, such as emergencies. “Obtaining informed consent can also be challenged in situations where a participant does not have the full ability to make a donation decision (e.g., some patients may be in intensive care units) (Kirillova et al.).

An additional problem faced in the field of 3D printing across the U.S. pertains to copyright claims. “​​Patents with a finite duration usually provide legal protection for proprietary manufacturing processes, composition of matter, and machines” (Hoy). In light of such restrictions, it can be necessary for people to arrange licensing agreements with patent owners if they would like to sell or distribute their versions of a 3D printed patented item. This is because distribution without permission could breach patent law (Bartlett). In one case, a designer filed a copyright takedown notice urging that a 3D file repository remove another participant’s design (Bartlett). Despite copyright-related and other issues associated with 3D printing, this technology should not be sidelined but monitored to ensure that it is used in positive ways. 

Future Trends

Over the coming years, 3D printing will likely play a vital role toward increasing personalized medicine in the U.S. through its use in customizing human tissues and organs. Furthermore, this technology can enhance prescription drug manufacturing processes and is “...expected to be especially common in pharmacy settings” (Ursan et al.). The current manufacturing and distribution infrastructure of drugs by pharmaceutical companies worldwide may be overhauled by 3D printing technology. This technology can rid current drug manufacturing structures of inefficiencies by “...emailing databases of medication formulations to pharmacies for on-demand drug printing” (Schubert et al.). In the event that medications start to be dispensed and created through this new format, patients may limit their medication to one daily polypill. This, in turn, can vastly improve medication compliance. 

In addition to medication fabrication, one of the most widely anticipated future applications of 3D printing in the U.S. concerns bioprinting complex tissues and organs. “This will open the door to making viable live implants, as well as printed tissue and organ models for use in drug discovery” (Lipson). One related method concerns in situ printing. This process occurs when implants or living organs are printed within or on the human body during operations. “In situ bioprinting for repairing external organs, such as skin, has already taken place” (Ozbolat, Yu). This encouraging turn of events can result in the use of bioprinting on an internal level. “Through use of 3D bioprinting, cells, growth factors, and biomaterial scaffolding can be deposited to repair lesions of various types and thicknesses with precise digital control” (Cui et al). In fact, there has been discussion in U.S. medical technology conferences about the creation of a handheld 3D printer for use in situ. This device could provide direct tissue repair (Cui et al.). Outside of surgical settings, such bioprinting functionality may include the ability to print out patients’ tissues in strips to gauge which medications can be most effective. 

Concluding Remarks

3D printing is a promising field with multiple beneficial applications across the U.S. when used ethically. From personalized surgery to enhanced medication distribution, the outcomes of such technology will likely revolutionize the U.S. healthcare arena. Moreover, the evolution of the 3D printing field offers exciting prospects for a variety of upcoming medical advancements that can enhance countless lives. To ensure that such technology develops in positive ways, it is important that medical professionals work together to create a cohesive set of related testing methodologies and regulations. Although this technology is still in its infancy, its potential for improving the quality of healthcare nationwide is truly promising.

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