NIH and FDA on 3D Printing in Medical Applications: Views for On-demand Drug Printing, in-Situ direct Tissue Repair and Printed Organs for Live Implants
UPDATED on 4/5/2016
Update on FDA Policy Regarding 3D Bioprinted Material
Curator: Stephen J. Williams, Ph.D.
UPDATED on 11/12/2015
NIH Considers Guidelines for CAR-T therapy: Report from Recombinant DNA Advisory Committee
FDA Guidance on Use of Xenotransplanted Products in Human: Implications in 3D Printing
FDA Guidance Documents Update Nov. 2015 on Devices, Animal Studies, Gene Therapy, Liposomes
FDA Cellular & Gene Therapy Guidances: Implications for CRSPR/Cas9 Trials
New FDA Draft Guidance On Homologous Use of Human Cells, Tissues, and Cellular and Tissue-Based Products – Implications for 3D BioPrinting of Regenerative Tissue
FDA Guidance on Use of Xenotransplanted Products in Human: Implications in 3D Printing
FDA Guidance Documents Update Nov. 2015 on Devices, Animal Studies, Gene Therapy, Liposomes
FDA Cellular & Gene Therapy Guidances: Implications for CRSPR/Cas9 Trials
New FDA Draft Guidance On Homologous Use of Human Cells, Tissues, and Cellular and Tissue-Based Products – Implications for 3D BioPrinting of Regenerative Tissue
SOURCE
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4189697/
FUTURE TRENDS
3D printing is expected to play an important role in the trend toward personalized medicine, through its use in customizing nutritional products, organs, and drugs.3,9 3D printing is expected to be especially common in pharmacy settings.5 The manufacturing and distribution of drugs by pharmaceutical companies could conceivably be replaced by emailing databases of medication formulations to pharmacies for on-demand drug printing.1 This would cause existing drug manufacturing and distribution methods to change drastically and become more cost-effective.1 If most common medications become available in this way, patients might be able to reduce their medication burden to one polypill per day, which would promote patient adherence.5
The most advanced 3D printing application that is anticipated is the bioprinting of complex organs.3,11 It has been estimated that we are less than 20 years from a fully functioning printable heart.8 Although, due to challenges in printing vascular networks, the reality of printed organs is still some way off, the progress that has been made is promising.3,7 As the technology advances, it is expected that complex heterogeneous tissues, such as liver and kidney tissues, will be fabricated successfully.9 This will open the door to making viable live implants, as well as printed tissue and organ models for use in drug discovery.9 It may also be possible to print out a patient’s tissue as a strip that can be used in tests to determine what medication will be most effective.1 In the future, it could even be possible to take stem cells from a child’s baby teeth for lifelong use as a tool kit for growing and developing replacement tissues and organs.3
In situ printing, in which implants or living organs are printed in the human body during operations, is another anticipated future trend.13 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.10 In situ bioprinting for repairing external organs, such as skin, has already taken place.13 In one case, a 3D printer was used to fill a skin lesion with keratinocytes and fibroblasts, in stratified zones throughout the wound bed.13 This approach could possibly advance to use for in situ repair of partially damaged, diseased, or malfunctioning internal organs.13 A handheld 3D printer for use in situ for direct tissue repair is an anticipated innovation in this area.10 Advancements in robotic bioprinters and robot-assisted surgery may also be integral to the evolution of this technology.13
Medical applications for 3D printing are expanding rapidly and are expected to revolutionize health care.1Medical uses for 3D printing, both actual and potential, can be organized into several broad categories, including:
- tissue and organ fabrication;
- creation of customized prosthetics, implants, and anatomical models; and
- pharmaceutical research regarding drug dosage forms, delivery, and discovery.2
The application of 3D printing in medicine can provide many benefits, including:
the customization and personalization of medical products, drugs, and equipment;
- cost-effectiveness;
- increased productivity;
- the democratization of design and manufacturing; and
- enhanced collaboration.1,3–6
However, it should be cautioned that despite recent significant and exciting medical advances involving 3D printing, notable scientific and regulatory challenges remain and the most transformative applications for this technology will need time to evolve.3–5,7
A number of fairly simple 3D-printed medical devices have received the FDA’s 510(k) approval.17
COMMON TYPES OF 3D PRINTERS
All 3D printing processes offer advantages and disadvantages.3 The type of 3D printer chosen for an application often depends on the materials to be used and how the layers in the finished product are bonded.11 The three most commonly used 3D printer technologies in medical applications are: selective laser sintering (SLS), thermal inkjet (TIJ) printing, and fused deposition modeling (FDM).10,11 A brief discussion of each of these technologies follows.
Selective Laser Sintering
An SLS printer uses powdered material as the substrate for printing new objects.11 A laser draws the shape of the object in the powder, fusing it together.11 Then a new layer of powder is laid down and the process repeats, building each layer, one by one, to form the object.11 Laser sintering can be used to create metal, plastic, and ceramic objects.11 The degree of detail is limited only by the precision of the laser and the fineness of the powder, so it is possible to create especially detailed and delicate structures with this type of printer.11
Thermal Inkjet Printing
Inkjet printing is a “noncontact” technique that uses thermal, electromagnetic, or piezoelectric technology to deposit tiny droplets of “ink” (actual ink or other materials) onto a substrate according to digital instructions.10 In inkjet printing, droplet deposition is usually done by using heat or mechanical compression to eject the ink drops.10 In TIJ printers, heating the printhead creates small air bubbles that collapse, creating pressure pulses that eject ink drops from nozzles in volumes as small as 10 to 150 picoliters.10 Droplet size can be varied by adjusting the applied temperature gradient, pulse frequency, and ink viscosity.10
TIJ printers are particularly promising for use in tissue engineering and regenerative medicine.10,13Because of their digital precision, control, versatility, and benign effect on mammalian cells, this technology is already being applied to print simple 2D and 3D tissues and organs (also known as bioprinting).10 TIJ printers may also prove ideal for other sophisticated uses, such as drug delivery and gene transfection during tissue construction.10
Fused Deposition Modeling
FDM printers are much more common and inexpensive than the SLS type.11 An FDM printer uses a printhead similar to an inkjet printer.11 However, instead of ink, beads of heated plastic are released from the printhead as it moves, building the object in thin layers.4,11 This process is repeated over and over, allowing precise control of the amount and location of each deposit to shape each layer.4 Since the material is heated as it is extruded, it fuses or bonds to the layers below.4 As each layer of plastic cools, it hardens, gradually creating the solid object as the layers build.11 Depending on the complexity and cost of an FDM printer, it may have enhanced features such as multiple printheads.11 FDM printers can use a variety of plastics.11 In fact, 3D FDM printed parts are often made from the same thermoplastics that are used in traditional injection molding or machining, so they have similar stability, durability, and mechanical properties.4
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