3D Bioprinting

Sindhu M 

Indian Institute of Science, Bengaluru

A group of 15-20 bioengineers huddled around a machine while Vikas Garg explained how it could someday be the future of food technology. The machine is a 3D printer, which can shape silicone, a notoriously difficult material. Vikas is the co-founder of Prayasta, a startup that currently 3D prints personalised soft tissue implants and prostheses at the Indian Institute of Science (IISc), Bangalore. He envisions burgers being printed on a conveyor line using 3D printing in the near future.  

In 3D printing, an object can be constructed based on a CAD file- a three-dimensional blueprint of the object of choice. The material used to construct the object is called ‘ink’. Scientists have even used biopolymers as ink and have developed the process of 3D bioprinting. Thus, 3D bioprinting may be used to ‘print’ tissues and organs. The ink used for 3D bioprinting is typically in liquid form at the beginning and is placed inside the nozzle of the printer. As it comes out of the nozzle, it is exposed to UV light, which converts the liquid into a solid form. 

While bioprinting functional organs is a distant reality, scientists are already printing non-functional organs to study their mechanical properties. 3D bioprinting is also used in healthcare. For instance, 3D printed breast implants for cosmetics have already entered clinical trials.

Conventionally, scientists studied tissues by growing cells in flasks. These cells formed a 2D sheet on which biologists performed experiments, such as drug testing. Drug testing, however, has a ridiculously low success rate– a mere 5-10% and could cost over a billion dollars per drug. 3D tissues engineered using 3D bioprinting would be a better model system for experiments such as drug development and drug testing. 

Cells in our body attach to and grow on top of a jelly like substance called the extracellular matrix (ECM). Scientists use bio-ink made-up of ECM components and using 3D bioprinting, shape it into a tissue scaffold. Cells are then allowed to grow on top of the engineered ECM to mimic a human tissue. Dr Kaushik Chatterjee, Associate Professor at the Department of Materials Engineering, IISc used a substance called κ-carrageenan, which is found in connective tissues of our body for 3D bioprinting, and showed that cells can be cultured on the engineered substrate. His group also used silk fibroin to bioprint scaffolds for bone tissue regeneration. 

Researchers from the Wake Forest Institute for Regenerative Medicine have already used 3D bioprinting to print a prototype kidney, and grafts for the airway and blood vessels. They are hopeful that it may be possible to 3D bio print entire functional organs in the future and use them for organ transplantation.