Scientists have developed more than ten different human organ chips, including devices to mimic critical functions of the lungs, kidneys, and intestines. Eventually, this technology could render animal testing obsolete.
Recently, researchers have demonstrated the feasibility of the organs-on-a-chip platform in studying how drugs are transported across the human placental barrier.
Some maternally-administered medications can enter the foetal bloodstream, but how the placenta determines which molecules can get through is still poorly understood. The ways of testing this process are limited.
Animal models don’t capture important details of human physiology, most in vivo research can’t be ethically performed, and placentas donated after birth are only viable for a few hours, making it difficult to properly conduct complicated transport experiments.
A small number of drugs have been tested via this ‘ex vivo placental perfusion’ method, however, by comparing the results of transport experiments conducted on their placenta-on-a-chip, researchers demonstrated their benchtop system could be an effective stand-in for a living organ in such research.
The researchers’ organ-on-a-chip is a small block of silicone that houses two microfluidic channels separated by a porous membrane. The researchers grow human trophoblast cells on one side of the membrane and endothelial cells on the other.
By adding different molecules to the blood-like fluid flowing through the ‘maternal’ microfluidic channel, the researchers can measure the rate at which they transfer to the ‘foetal’ channel and how much they accumulate in the barrier itself.
What are organs-on-a-chip?
- An organ-on-a-chip (OOC) is a multi-channel 3-D microfluidic cell culture chip that simulates the activities, mechanics and physiological response of entire organs and organ systems;
- They are a type of artificial organ; and
- They constitute the subject matter of significant biomedical engineering research.
How can organs-on-a-chip aid drug development?
A major issue with the current drug development process is the use of animals for research, which is required for regulatory approval, can take years to complete, and often does not predict clinical responses in humans.
The aim of organs-on-a-chip is that instead of testing new drugs or supplements on animals, researchers can use these chips. Each chip is about the size of a human thumb and contains tiny channels filled with living human cells that imitate the functions of different organs.
In 2017, the US Food and Drug Administration agreed to a research and development collaboration that could potentially reduce the number of animals used for health research.
Currently the guiding principles underpinning the humane use of animals in scientific research are called the three R’s. Any researcher planning to use animals in their research must first show why there is no alternative and what will be done to minimise numbers and suffering, i.e.:
- Replace the use of animals with alternative techniques, or avoid the use of animals altogether;
- Reduce the number of animals used to a minimum, to obtain information from fewer animals or more information from the same number of animals; and
- Refine the way experiments are carried out to make sure animals suffer as little as possible. This includes better housing and improvements to procedures which minimise pain and suffering and/or improve animal welfare.