[Reading Science] Animal Testing Ends, Now Experimenting with 'Janggi Chip'?

Cells that make up human organs are cultured and placed into a 'chip,' known as an 'organ chip,' which is becoming commercialized.
[Photo by YouTube screen capture]

[Asia Economy Reporter Kim Jong-hwa] Research to treat human diseases, that is, new drug development research, cannot be conducted directly on humans. Therefore, 'animal testing' using animals is performed instead. The data obtained from animal testing is expected to be similarly applicable to humans.

Animal testing is based on the premise that genetic phenomena, material and energy metabolism, and other basic systems in animals are the same as those in humans. Developing a new drug involves several stages. First, there is the 'discovery' stage, where candidate substances are identified and foundational technologies are researched. Next, there is the stage of selecting development candidate substances.

After selecting candidate substances, there is the 'preclinical trial' stage, where the efficacy of the substances is tested on animals. If efficacy is confirmed in animals, the final stage is the 'clinical trial' stage, where the drug is applied to actual humans. To proceed to the final clinical trial stage, it is essential to verify the side effects or toxicity of the new drug through animal testing.

Once the clinical trial stage confirms that the drug is effective without significant side effects in humans, it can move on to 'new drug approval and marketing.' The third stage, the preclinical trial stage, i.e., animal testing, most commonly uses animals called 'white mice,' commonly known as laboratory mice.

Depending on the characteristics of the new drug, experiments may be conducted on various animals such as rabbits and primates like monkeys. However, animal testing has clear limitations. Above all, the biggest limitation is that animals and humans are fundamentally different. Many cases exist where a new drug that showed efficacy without side effects in animal testing causes side effects or loses effectiveness when applied to humans.

One of the reasons for the low success rate in new drug development is the 'difference between animal testing and human clinical trials.' What works in animals but not in humans ultimately means that humans and animals are different, which does not imply that animal testing is unnecessary for human new drug development.

'Eye chip' cultured with human corneal and conjunctival cells inside a chip
Photo by YouTube screen capture

Is there a way to obtain experimental data beyond animal testing? That method is 'Organ on a chip,' or 'Janggi chip' in Korean. Scientists, after much consideration, devised a method to create tissue similar to human organs and conduct experiments using that tissue.

An organ chip is created by culturing specific human organ cells and placing these cells inside a mechanical chip. It is designed to mimic the physiological characteristics of the respective organ as closely as possible. The world's first developed organ chip is the 'lung organ chip' created by Professor Dong-eun Huh's team at the University of Pennsylvania, USA. This organ chip contains lung and capillary cells inside the chip, connected to a vacuum pump, allowing the lung to repeatedly contract and expand as if breathing.

Capillary cells have a structure similar to blood vessels, allowing blood to flow through, functioning like actual lungs by exchanging oxygen and carbon dioxide. It is designed to physiologically respond like real lungs to various substances encountered daily, such as drugs or toxic materials.

Although about the size of a fingertip joint, in terms of function, it is no different from an actual human lung. Therefore, testing candidate substances for new drugs on this chip can provide more accurate information about their effects and side effects than animal testing. Because actual human cells, not animals, are used, the reliability of the experimental results is considered much higher than that of animal testing.

Since the development of the lung organ chip, a global boom in organ chip development has occurred. Patent applications, which numbered 14 in 2009, began to surge after the European Union banned the manufacture and sale of cosmetics tested on animals, reaching 77 in 2017, nearly a fivefold increase. In South Korea, since February 2017, cosmetics tested on animals cannot be distributed or sold.

Worldwide patent types include 20% for cell culture-related materials and 18% for devices, 12% for sensor devices implemented within chips, and 10% for drug testing methods using device chips. Organ chip development is also accelerating domestically. 'Curiochips,' a venture company founded by Seoul National University, has succeeded in independently developing human organ chips and is attempting commercialization.

In 2011, the 'heart chip,' which precisely mimics the function of the heart, was developed, followed by the development of the 'eye chip,' which blinks and performs cell movement like a real human eye, as well as the 'kidney chip' and 'skin chip.' The 'skin chip' has already been commercialized and is used in toxicity testing during cosmetic development.

Chips can be made for each major organ of the human body, allowing experiments to be conducted using these chips instead of animals. In the near future, it is expected that organ chips with multiple organs placed on a single chip will also be developed. [Image captured from YouTube]

Recently, the focus has shifted to developing 'customized chips.' This involves extracting cells from the lungs of a patient suffering from lung cancer to create a lung organ chip. This is the patient's 'mini avatar organ' made from their own cells. Using this chip, the most effective drug among various lung cancer treatments can be identified and applied for treatment.

However, currently, organ chips remain at the level of mimicking the function of specific organs. Scientists now dream of developing future organ chips that place multiple organs on a single chip. This concept of organ chip is called 'Human on a chip.'

Last year, about 3.7 million experimental animals were sacrificed in South Korea alone, and over 100 million worldwide. Professor Dong-eun Huh, who developed the lung organ chip, predicted, "Technology that can completely replace animal testing will be developed within 20 years." We hope the day when animals are no longer sacrificed for humans comes as soon as possible.