Layering cells and growth factors to create tissue-like structures that imitate nature.
Research into the 3D-printing of organs has resulted in functioning tissue networks that can be used in the human body. The two crucial ingredients, cells and an extracellular matrix, are deposited into a 3D gel. Then, working layer by layer, the required tissue is ‘printed’. Using the patient’s own cells as a foundation means the replacement organ is less likely to be rejected by the host. The patient, therefore, won’t need to take immunosuppressant drugs, making them less susceptible to disease during the transplant process.
The global 3D Bio-printing market is expected to reach $2.6bn by 2024. Growing use of 3D printing in cosmetic surgery and drug testing, coupled with increasing demand, is expected to drive market growth during the forecast period. 3D bio-printing is currently used for printing medical instruments, prosthetics, and dental and bone implants. Its application in pharmaceutical manufacturing is expected to grow, reducing the overall cost of drug production. While most organs are still in the early stages of development, some success has already been demonstrated, especially in the area of skin and bone.
A current leader in 3D printing tissues and organs is Organovo Holdings Inc, which already bio-prints liver and kidney tissues for research. Its human liver tissue patch trials in mice have demonstrated success. The company is targeting partial liver transplants for human trials in 2020. This technology could prove to be vital for extending the lives of patients on long waiting lists.
Of the complex organs set for bio-printing, the heart is forecast to be the first completed. This is because, as crucial as it is, the heart’s primary function is to pump, rather than process complex biochemical reactions. The biotech startup Biolife4D has already produced human cardiac tissue. Their ‘cardiac patch’ uses a patient’s white blood cells and has multiple cell types used by the human heart. Ravi Birla, BioLife4D’s chief science officer, said that the ability to bioprint human cardiac tissue provides a “clear and rapid pathway towards bioprinting human hearts.” The company is working on creating miniature hearts for testing in small animals later this year.
Another bio-printing startup Aether has entered the world of medical imaging software. Combining imaging with its bio-printer and bio-inks, it hopes to convert raw medical images into segmented, 3D printable files. From these files doctors can create implantable organs.
A team at Harvard is tackling the difficulties of bio-printing kidneys by using ‘bio-ink’ made from kidney cells and surrounding material. The ink, which has the consistency of toothpaste, can be molded at room temperature. This has allowed the researchers to make complex tissue structures, such as the blood-filtering kidney component called the nephron.
A team from the University of Glasgow in Scotland has grown 3D samples of mineralized bone for the first time, using a newly-developed technique called “nanokicking”. This technique vibrates the stem cells at the frequencies they have evolved to be vibrated by the body, stimulating their natural regenerative mechanisms. The researchers were able to convert human stem cells into 3D bone grafts following successful animal trials. The grafts could be ready for implantation as early as 2020, providing future treatment for osteoporosis.