6.4

Advantages of Using Organs-on-a-Chip as In Vitro Model

Organs responsible for respiratory system, central nervous system, hepatic system,

and cardiovascular system, as well as lymph junction and mammary gland, have all

been created using ‘organ-on-a-chip’ technology. Several researchers are trying to

construct a 2D, 2D+, or 3D architectural design with oxygenation to better simulate

the in vivo environment. They may, however, have some major advantages over

conventional safety, efficacy, and toxicity testing methods:

1. Biology in 3D is superior to 2D biology.

2. Ideal for use as a barrier.

3. Replicates hormonal flows.

4. Extracellular matrix can be thick for drug/factor binding.

5. Support the relationships between organs.

6. Sufficient tissue for tens to thousands of variable multi-omics studies.

7. Minimal media volumes are needed.

8. It is possible that drug prices will drop in the future due to less failures in clinical

trials.

9. It is possible that 1 day a separate-patient miniature will be designed.

10. It is possible that animals-on-chips would be possible in the future.

6.5

Role of 3D Bioprinting in Developing Organ-on-a-Chip

and Its Uses

A significant advancement in a key engineering, manufacturing, education, as well

as design and health sectors has come from the widespread use of 3D (or ‘additive’)

printing. Biocompatible components and biointeractive cell parts can now be 3D

printed to create living tissues. To meet the demand for transplantable tissues and

organs, 3D bioprinting is used in tissue regeneration engineering (Chen and Liu

2016). 3D bioprinting is more complicated than non-biological printing due to

substrate choice, types of cells, proliferation and differentiation variables, and

technical difficulties associated with the susceptibilities of living cells or tissues

construction. To address these issues, engineering, biomaterials research, cell biol-

ogy, physics, and medicine must all be combined (Doke and Dhawale 2015). Several

tissues, including multilayered skin, bone, vascular grafts, tracheal splints, cardiac

tissue, and cartilaginous structures, have already been created and transplanted using

3D bioprinting. Other applications include the creation of elevated 3D-bioprinted

in vitro studies for experimentation, drug development, and toxicology (Yan et al.

2018). Figure 6.2 depicts the process of 3D bioprinting.

Charles Hull, an American engineer, invented the first 3D printer in the early

1980s, which used computer-aided way to design solid objects (CAD). By deposit-

ing various combinations of an acrylic-based photopolymer and crosslinking them

concurrently with UV light, the printer created a solid 3D object. A fundamental

technique, stereolithography (SLA), has revolutionized the additive manufacturing

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G. Aggarwal et al.