Rapid advancements in technology are so commonplace in our modern era that new developments rarely elicit surprise, regardless of how extraordinary they may be. While many people may be unfazed by the current rate and scale of invention, it is crucial that the implications of these innovations not be overlooked. Over the last few decades, additive manufacturing or 3-D Printing as it is more colloquially known, has grown rapidly in sophistication and is inspiring visions (for better or worse) of everything from zero-gravity manufacturing to homemade firearms. Not long after its inception, the significance of 3-D printing to healthcare and biomedical research was realized, and the technology has received increasing interest in its potential applications for medical and bioengineering purposes.
A Brief Background
The origins of 3-D printing can be traced back to the 1980’s, when a man named Charles W. Hull developed a process by which solid objects could be constructed through the successive ordering of thin layers of photopolymer. He dubbed this production method “stereolithography” and was awarded a U.S. Patent in March of 1986. Initially, this process was envisioned as a means by which three dimensional models could be subjected to testing and evaluation prior to large scale manufacturing investments; it was soon realized, however, that the possibilities were much greater.
Around the turn of the century, medical researchers began to make breakthroughs in their work with additive manufacturing. Scientists at the Wake Forest Institute for Regenerative Medicine first developed and then successfully implanted bladders into seven patients suffering from a congenital condition known as myelomeningocele. These bladders were constructed around scaffolds using biopsied cells from the patients, a process which, compared to traditional protocols, minimized the risk of rejection. A few years later, researchers at the same institution would engineer a fully functional miniaturized kidney, inspiring optimization for the future of organ transplant and joint reconstruction procedures.
Since these initial successes, additive manufacturing technology has seen further triumphs, including the successful production of a 3-D printed prosthetic leg (by what would subsequently become Bespoke Innovations), as well as the creation of the first 3-D printed blood vessels by San Diego-based Organovo. Along with numerous other milestones, these innovations helped to drive the appendage of 3-D printing known as “bioprinting”, the process by which human tissue is generated via additive manufacturing.
Dr. Darryl D’Lima is one such researcher who believes in the promise of bioprinting. As director of the Shiley Center for Orthopaedic Research and Education (SCORE) at the Scripps Clinic in San Diego, Dr. D’Lima has been exploring the use of bioprinting for restoring knee cartilage in orthopedic patients. After finding success in printing bioartificial cartilage in cow tissue, D’Lima eventually printed human cartilage from knee replacement patients. Using a modified HP inkjet printer from the 1990’s, he was able to produce a mixture of cartilage progenitor cells along with a serum that congeals when exposed to UV light. While the scientific premise has been worked out, however, there is still much work to do in the way of engineering.
For years, much hype surrounded the possibility that 3-D printers could eventually be used to manufacturing living organs for transplant patients. And while that may someday come to fruition, many daunting obstacles remain in place. For Dr. D’Lima, generating a simpler living tissue like cartilage is both significant and attainable.
Currently, patients requiring knee reconstruction are faced with the prospect of having an artificial joint surgically implanted, a procedure that is both painful and often impermanent. With his research utilizing bioprinting as a means of repair, Dr. D’Lima is seeking to produce living tissue onsite in the operating room so that the required components of joints and bones can be ready on demand. The more established methods of generating tissue in a lab are time intensive and require extensive manipulation to meet the high specificity of a human joint. Additionally, the transplant process adds further complications. The chondrocyte cells that compose cartilage, however, require less nourishment than the cells of other tissues, meaning the difficulties involved in printing are lessened to a degree. It is for this reason that, despite facing a number of challenges that include finding a bountiful source for the cartilage cells (potentially stem cells) and a gel material that will eventually degrade while leaving the chondrocyte matrix intact, Dr. D’Lima and his team are “cautiously optimistic” about their efforts.
The market for knee replacements is lucrative, with a global market projected to exceed $10 billion in the next few years. If bioprinting, along with other developing technologies, continue to advance, we may soon see these innovations revolutionize healthcare as we know it.