Bioprinting, an offshoot of 3D printing, aims to allow scientists to build organs, layer by layer. Researchers have already built modified 3D printers and are now perfecting the processes that will allow them to ultimately print tissues and organs for transplantation. Getting these printed cells to behave like native cells is a challenge. As the technology improves, the next step will be fully functional replacement organs, complete with the vascularization necessary to remain alive and healthy. Some of the latest achievements in 3D bioprinting are described here.
3D-PRINTED OVARY IMPLANTS FOR FERTILITY
Scientists at Northwestern University have used a 3D printer to create a prosthetic ovary. To test the implant, researchers removed the ovaries of mice and replaced them with the ovary bioprosthesis. Following the procedure, the mice ovulated, gave birth to healthy pups, and were able to nurse. These results were presented on April 2 at the Endocrine Society's annual meeting in Boston. Researchers hope to use the technology to develop an ovary bioprosthesis that could be implanted in women to restore fertility. One group that could benefit is survivors of childhood cancers, who have an increased risk of infertility as adults.
Using a 3D printer, the researchers created a scaffold to support hormone-producing cells and oocytes. The structure was made out of gelatin. Biological principles were applied to manufacture the scaffold, which needed to be rigid enough to be handled during surgery and to provide enough space for oocyte growth, blood vessel formation, and ovulation. Using human cell cultures, the researchers determined the optimal scaffold design should have crisscrossing struts that allowed the cells to anchor at multiple points. The scaffolds were seeded with ovarian follicles to create the bioprosthesis.
Implanting the prosthetic ovary in mice also restored the estrous cycle. Researchers theorize that a similar implant could help maintain hormone cycling in women who were born with or have undergone disease treatments that have reduced ovarian function. These women often experience decreased production of reproductive hormones that can cause issues with the onset of puberty as well as bone and vascular health problems later in life. (For more information, see the release.)
THE HANDHELD BIOPEN FOR ARTHRITIS
Arthritis is a debilitating condition that breaks down the cartilage between joints. Although joint replacement remains a viable option for patients, orthopedic surgeons are looking for new ways to treat the condition in its early stages. The Australian Research Council Centre of Excellence for Electromaterials Science has developed the BioPen to help orthopedic surgeons design customized implants during surgery (see case study). Researchers say the BioPen is a mobile version of 3D printing, putting that capability directly into the hands of the surgeon.
These customized implants are supported by the patient’s own live cells and growth factors to accelerate the regeneration of functional bone and cartilage. The BioPen uses 3D printing methods to deliver cell material inside a biopolymer, which is protected by a second, outer layer of gel material. The two layers are combined in the pen head, allowing the surgeon to “draw” the ink on the damaged bone. A low-powered ultraviolet light source fixed to the device solidifies the inks to protect the embedded cells during dispensing. Once in the body, the cells multiply; differentiate into nerve cells, muscle cells, or bone cells; and eventually become a thriving community of cells in the form of a functioning tissue.
The new research was featured in the journal Biofabrication. The study showed that one week after drawing/printing the cells, 97% of the human cells maintained high viability. According to the study, the BioPen paves the way for the use of 3D bioprinting during the surgical process and personalizes the process to each person.
3D BIOPRINTING FOR GUM DISEASE
Griffith University researchers are pioneering the use of 3D bioprinting to replace missing teeth and bone (see release). The three-year study has been granted a $650,000 National Health and Medical Research Council Grant and is being undertaken by Professor Saso Ivanovski from Griffith's Menzies Health Institute Queensland.
The approach begins with a scan of the affected jaw, prior to computer-aided design of a replacement part. Says Ivanovski, "A specialized bioprinter, which is set at the correct physiological temperature (in order to avoid destroying cells and proteins), is then able to successfully fabricate the gum structures that have been lost to disease—bone, ligament, and tooth cementum—in one single process. The cells, the extracellular matrix, and other components that make up the bone and gum tissue are all included in the construct and can be manufactured to exactly fit the missing bone and gum for a particular individual."
Currently in preclinical trials, Professor Ivanovski says the aim is to test the new technology in humans within the next one to two years. Regarding the anticipated cost of treatment, he said that this should be a less costly way of augmenting deficient jaw bone, with the savings expected to be passed on to the patient.
The list of remarkable accomplishments that are being enabled by bioprinting is long. The above cases are representative of a few that have been reported most recently. R&D Magazine has compiled a list of companies that are developing 3D bioprinters and associated equipment, processes, and technologies. Many of these technologies and their cutting-edge applications will be discussed in depth at an October 2016 gathering in Boston, “BioPrinting: Beyond the Scaffold” (BCC Research).