CHEARS

3D printing has been an exciting innovation where one can create various items with printing them in their 3D formats from a digital file. Imagine 3D printing the different organs of the body which can then be used to replace them in individuals suffering from various diseases and in turn saving lives! This would give rise to a whole new world in biology and open up wide array of opportunities in terms of diagnostics and treatment. And hold behold! This technique has already been developed to such an extent, that this dream is not far from reality.

What is this technique?

Just like in printing we use different inks, 3D bioprinting is a technique that combines cells, growth factors, hydrogels, etc. to form “bioinks” which are then deposited layer by layer forming tissues and organs of the human body. These 3D bioprints plays an important role in the development and testing of different drugs. But, once they are vascularized or provided with blood supply and made them active similar to that of in-vivo system, they can be used as transplants in the body.

So how do they achieve this?

• The first step is data acquisition. Different techniques such as X-rays, CT scans, MRIs are used to scan the organ and reconstruct a model based on personalized sizes using computer software. These 3D models are then digitally segregated into various 2D slices based on different orientations and further processed to particle or filament forms based on the type of bioprinting approach used.

  
  

• The second step is material selection. Bioinks are produced with careful selection of the cells, growth factors required for the development of tissue/ organ. Cells can either be taken from the same individual where the transplantation would occur, from a different individual or a different organism altogether. One needs to remember during selection that the product should be biocompatible, should have mechanical properties and be printable.

  
  

• The third step is bioprinting. This is the crucial step, where bioprinters are used along with softwares that directs the formation of the 3D structure. Continuous observation is needed to avoid any problems. There are different ways bioprinting can be done.

  
  

The extrusion-based bioprinting produces continuous filamentous structures that develops into the particular tissue/ organ.

The droplet-based bioprinting produces droplets which will coalesce together to form tissue/ organ.

The photocuring-based bioprinting produces layers of a particular structure that will stack together to form a tissue/ organ.

• The fourth step is functionalization. Once bioprints are formed, we need to ensure that the different cells have a mechanical and chemical connection between them and to act similar to natural organs, they should be provided with blood supply and ensured for its correct and proper functioning. Hence, they are kept in bioreactors that will provide them with nutrients, a microenvironment, etc. for the maturation, vascularization of tissues and to make them viable for transplants.

  
  

Currently, many trials have been made to produce organs such as skin, heart, kidneys, bones, bladder, cornea, liver, ear etc. with successful implantation of bladder in an individual. However, majority of these organs being complex in nature have encountered limitations with vascularization, viability, etc. and hence cannot be transplanted into individuals successfully yet. But research is on, and we hope that they get resolved in the near future for the benefit of humankind.