Changing the future of medicine with 3D BioprintingLeave a Comment
The creation of artificial human tissues and organs may sound like a futuristic dream, but it is happening right now. Research institutes and hospitals around the globe have been working on bioprinting applications, which are providing new options for treatment and scientific study. Potentially, 3d bioprinting will be the next big thing in health care and personalised medicine.
The idea of printing human organs, has its origins in the invention of stereolithography in 1983. This special type of 3D printing relied on a laser to solidify a polymer material extruded from a nozzle. However, the material used in this process was not robust enough to create a long-lasting structure. By the early 1990s, the next generation of materials was introduced. Called nanocomposites, they were blends of plastics and powdered metals. These materials were more durable. They made possible the scientist to produce longer lasting end-products.
It did not take long for medical researchers to notice the protentional of such materials and 3d printing technology in clinical application. In 1999, scientists at the Wake Forest Institute for Regenerative Medicine used a 3D printer to build a synthetic scaffold of a human bladder. They then coated the scaffold with cells taken from their patients and successfully grew working organs. This set the stage for true bioprinting. In 2002, scientists printed a miniature functional kidney capable of filtering blood and producing urine in an animal model. And in 2010,Organovo printed the first blood vessel. Today, 3d bioprinting companies like Cellink, Allevi , Regemat or SunP are focusing on printer and living inks development to provide future opportunities for complex organ printing.
Within bioprinting, there are three main technologies, namely inkjet, extrusion, and laser-assisted printing. Inkjet printers possess a print-head that generates a pressure pulse (either thermally or acoustically) that forces droplets from the nozzle. Laser-assisted printers use pressure generated by a laser to propel cell-containing material from an absorbing substrate onto a collect substrate. Finally, and most commonly used, are extrusion printers that use pneumatic or mechanical piston/screw dispensing systems to extrude continuous beads of bio-ink.
There are also different biomaterials which are reported as bioinks for 3D bioprinting. They are the Agarose-based, Alginate-based, Collagen-based, Hyaluonic acid-based, Fibrin-based, Cellulose-based, Silk-based and Synthetic biomaterials. Each class of bioink has pros and cons, however, they have a common requirement for control of mechanical and biological properties of the printable material.In terms of mechanical control, it is imperative that the bioink forms a microstructure which mimics that of the cell’s native environment. As well as a familiar architecture, the gel stiffness and porosity should be matched to that found in vivo so as to support cell growth, signalling, and proliferation. Ideally, the bioink will exhibit shear-thinning behaviour, as this will reduce the stress exerted on the cells during the printing process, which most commonly involves extrusion of the bioink through a narrow print-head. In order to assure biocompatibility, the raw materials used for the production of the bioink should not be cytotoxic to the cells in question, nor elicit an immune or inflammatory response.
Using a combination of the right printing process and bioink, researchers have already been printing bone and skin tissues in the labs. Whilst work towards the bioprinting of more complex internal organs, such as the liver, is happening today in research labs all across the world, it is anticipated that fully functioning lab grown versions of these are still at least 10 years away, possibly more.
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