Thousands of individuals are presently waiting on transplant lists for vital organs like

kidneys, hearts, and livers that could save their lives. Regretfully, there aren't enough

organ donors available to meet that need. What if we could make fresh, personalized

organs from scratch rather than having to wait? That's the concept underpinning the emerging field of bioprinting, which is a subspecialty of regenerative medicine. While

printing intricate organs is still out of the question, we can currently print simpler

tissues like blood vessels and the tubes that carry nutrients and waste out of the

body. The biological relative of 3-D printing, known as "bioprinting" is the process of

building three-dimensional objects one slice at a time by depositing layers of material

on top of one another.

A 3-D printer for organs and tissues starts with bioink, a printable substance that

incorporates living cells, as opposed to metal, plastic, or ceramic. The majority of

bioinks are hydrogels, which are polymers rich in water. Millions of living cells and

different substances that promote cell growth and communication are mixed in with

them. While some bioinks contain only one form of cell, others combine multiple

types to create more intricate structures.

Suppose your goal is to print a meniscus, the cartilage portion of the knee that

prevents the thighbone and shinbone from grating against one another. It is

composed of chondrocytes, which are necessary in sufficient quantities for your

bioink. These cells may be derived from donors whose cell lines have been

laboratory-replicated. Alternatively, they could come from the patient's own tissue to make a customized meniscus that the body is less likely to reject.

Extrusion-based bioprinting is the most widely used of the many printing methods.

This involves loading bioink into a printing chamber and forcing it via a printhead-

attached circular nozzle. It can create a continuous filament that is about the

thickness of a human fingernail and exits from a nozzle that is rarely wider than 400

microns in diameter. The strands are placed either onto a flat surface or into a liquid

bath that will assist hold the construction in place until it stabilizes, guided by an

image or file that has been computed. These printers are quick, creating the

meniscus one thin strand at a time in roughly thirty minutes. Certain bioinks will

solidify instantly upon printing, while others require exposure to UV light or an extra

chemical or physical procedure to maintain their structure.

The artificial tissue's cells will start to communicate with one another, exchange

nutrients, and proliferate just like actual tissue's cells do when the printing procedure

is effective. This meniscus and other comparatively simple structures are already

printable.

Additionally, bioprinted bladders have been implanted successfully, and printed

tissue has helped rats' facial nerves regenerate. Scientists have produced

microscopic, partially functional replicas of kidneys, livers, and hearts in addition to

lung tissue, skin, and cartilage.

There’s still a long way ahead.

Replicating a big organ's intricate biochemical environment is difficult, though.

If the nozzle size is too tiny or the printing pressure is too high, extrusion-based

bioprinting may result in a considerable percentage of the cells in the ink being

destroyed.

Getting oxygen and nutrients to every cell in a full-sized organ is one of the hardest

tasks. Because of this, hollow or flat structures have had the most success to date,

and scientists are currently working on creating methods for printing blood veins into

bioprinted tissue.

(OUTRO)

Bioprinting has the ability to save lives and improve our knowledge of how our

organs work in the first place. A bewildering array of possibilities is also made

possible by the technology, such as the ability to print tissues with integrated circuits.

Might we eventually create organs that are beyond the capabilities of humans or

provide ourselves with qualities like indestructible skin? For what length of time could

we prolong human life by printing new organs? And just who or what will have

access to this amazing technology and its output?