Manufacturing technology
implants that precisely match the patient’s anatomy, such as titanium alloy cranial repair plates,” says Professor Jianfeng Zang of the Huazhong University of Science and Technology, “whereas bioprinting enables the production of degradable scaffolds loaded with growth factors or drugs, such as PLA/ PCL scaffolds for cartilage repair.”
The need for tissue-engineered products in clinical settings has grown with a lack of organ donors and the increase in transplant rejection. This has meant there is an increased need for laboratory-generated implants that mimic human tissue. A lot of this was done in the past by seeding stem cells into scaffolds and implanting them in the body. However, this often failed to replicate human tissue. Now, continued advancements in additive manufacturing have led to the field of bioprinting. Bioprinting has been used to create a range of tissues and implants that could potentially be transplanted into the body, alongside biomimetic organ and disease models that help researchers study human physiology – which are helping clinicians to treat diseases more effectively. This is on top of conventional additive manufacturing being able to create metallic implants for a range of ailments. More recently, in vivo bioprinting – currently at an experimental stage – has attracted attention for its potential to print tissue constructs and implants at the site of need, which may improve integration. “Although in vivo bioprinting technology is based on conventional additive manufacturing, there are some differences,” says Zang. “We need to use small instruments with small lumens because the printing scenarios are very complex and deeper anatomical sites demand greater flexibility, and only biocompatible materials can be used to create the implant.” Both types of bioprinting involve embedding cells in a bioink (e.g. hydrogels and biomaterial scaffolds). For transplant-based bioprinting, the cells are incubated until the tissue fully forms, ready for implanting, whereas in vivo bioprinting directly deposits the bioink using a very small and flexible printing nozzle. While using light is one way to cure in vivo bioinks, Zang states that: “One of the most impressive emerging bioprinting advancements is acoustic volumetric printing, which delivers a liquid ‘sonic ink’ through catheters into the body, where external ultrasound triggers in situ solidification.”
Compared with conventional cell seeding approaches, bioprinting provides a uniform distribution of cells that allows tissues to be reconstructed accurately. “Compared with other methods, bioprinting can reach any desired location within human tissues through catheter structures,” says Zang. “Printing drug or medical devices directly onto tissues in a minimally invasive manner can help to heal damaged tissue and reduce the need for implant surgeries, so long as there’s
www.medicaldevice-developments.com
3D bioprinting: A market on the rise
The global 3D bioprinting market is set to more than double by 2030, reaching an estimated $2.8bn, driven by investments in regenerative medicine and AI-enhanced printing. North America remains the dominant region, with leading players pushing innovation in multi-material printing and sophisticated bio-inks. Emerging trends include the use of stem cells and organoids for drug testing. While costs and regulatory uncertainty remain hurdles, partnerships between universities and industry are accelerating progress. With clinical trials slowly moving from tissue models to implant applications, the market is poised to support a new generation of personalised, minimally invasive therapies. Source: Markntel Advisors
a seamless integration between the printed material and the biological matter inside the body.” Bioprinting can produce a range of customised implants that fix complex tissue defects with a much more efficient integration inside the body. This includes repairing cartilage, connective tissue, nerve structures, microvasculature and muscle tissue using a range of smart tissue patches, as well as implants that can enhance bone repair by delivering growth factors.
The move to clinical trials
While it may not be well documented, bioprinting is moving through clinical trials – much like advanced implants are using more traditional additive manufacturing methods. There have been clinical trials undertaken so far, most of which have focused on bioprinted in vitro models, but there have also been some implant clinical trials that have taken place too. For the bioprinting of in vitro models, the majority of clinical trials have targeted different cancers, including ovarian, haematological, colorectal and pancreatic cancers – which have been led by different hospitals. These trials have focused on bioprinting tumour tissues and organoids. The other in vitro model trials have focused on using tissue models as drug screening platforms for optimising the delivery of drug treatments. One of the other clinical trials undertaken includes an in vitro study on building skin substitute materials, and while this study was an in vitro study, the end goal of the skin is implantation. On the implant side, there are currently multiple clinical trials ongoing that are targeting different ailments. One example is using implanted bioprinted blood vessels to treat peripheral limb arterial disease, with the aims of the clinical trial focusing on device success rate and graft patency rate. Another example is the bioprinting of personalised tracheal structure implants for treating thyroid cancer, with the aims of these clinical trials focusing on the airway lumen opening rate, degree of granuloma formation and degree of inflammation. Two implant clinical trials have also focused on external medical conditions rather than internal ailments. One clinical trial has focused on treating microtia (underdeveloped ear). This clinical
Opposite: A clinical trial has focused on treating microtia via bioprinting.
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