Comparing Chip vs. Animal Models in Medical Research

September 26, 2023 - Medical research has come a long way in the quest to understand diseases, develop new treatments, and improve patient care. Two primary approaches used in this pursuit are microfluidic organ-on-a-chip systems and traditional animal models. Both methods have their merits and drawbacks, and choosing the right one depends on various factors, including research goals, ethical considerations, and technological advancements. This article will explore and compare these two approaches to better understand their applications in healthcare technology research. 

Organ-on-a-Chip Models 

Organ-on-a-chip models, often called microphysiological systems or organoids, are sophisticated miniature systems designed to mimic the structure and function of human organs on a microscale. These devices incorporate microfluidic channels, living cells, and other biological components to replicate the physiological conditions of specific organs, such as the heart, lung, liver, kidney — and even the vagina. 

Advantages of Organ-on-a-Chip Models 

• Human relevance: One of the most significant advantages of organ-on-a-chip models is their ability to closely mimic human physiology. They use human-derived cells, providing a more relevant platform for studying disease mechanisms and drug responses than animal models. 
• Precision medicine: Organ-on-a-chip models enable the testing of drugs on a patient-specific basis, potentially revolutionizing the field of precision medicine. Researchers can develop personalized treatments tailored to an individual's unique genetic makeup and disease profile. 
• Reduction in animal testing: Using organ-on-a-chip models can significantly reduce the need for traditional animal testing, aligning with ethical concerns and animal welfare regulations. 
• High-throughput screening: These models allow for high-throughput screening of drug candidates, accelerating the drug development process and reducing costs. 

Limitations of Organ-on-a-Chip Models 

• Complexity: Developing and maintaining organ-on-a-chip models can be technically challenging and labor-intensive, requiring expertise in microfabrication, biology, and engineering. 
• Limited organ complexity: Although these models can mimic individual organ functions, they might not comprehensively grasp the intricacies of interplay among various organs within the human body. Nevertheless, this situation is on the brink of transformation. Multiorgan-on-a-chip (multi-OoC) devices, which facilitate inter-organ communication, enable the examination of multiorgan processes and the creation of systemic disease models. Multi-OoC methodologies yield fresh perspectives that would otherwise be overlooked when using single-OoC models. 
• Cost: The upfront expenses associated with establishing organ-on-a-chip systems can be substantial. To illustrate, CN Bio Innovations offers a liver-on-a-chip device called the LiverChip, which begins at approximately $22,000. Nevertheless, this innovation boasts swifter results and significantly lower costs than traditional animal-based research, potentially making its long-term advantages outweigh the initial investment. 

Animal Models 

Animal models, which entail the utilization of animals, commonly rodents such as mice and rats, have been employed for numerous years in medical research to investigate diverse aspects of human biology, disease mechanisms, and pharmaceutical development. These models have been a staple in medical research for decades. 

Advantages of Animal Models 

• Whole-body systems: Animal models provide a comprehensive view of how drugs or treatments affect the entire organism, including interactions between different organs and systems. 
• Longitudinal studies: Researchers use long-term animal studies, often with primates like macaque monkeys, to observe disease progression and evaluate chronic treatments. For instance, in Parkinson's disease research, this approach has helped develop therapies for slowing or alleviating human chronic symptoms — including deep brain stimulation, cell transplantation, and levodopa therapy. 
• Translational potential: Findings from animal studies can often more readily translate into clinical trials and real-world applications. 
• Established knowledge: Extensive databases of animal research data are available, making it easier to compare and analyze results across different studies. For instance, research involving mouse models has led to the discovery of specific targeted therapies and immunotherapies. These promising findings have successfully transitioned into clinical trials, resulting in new treatments like immune checkpoint inhibitors, which have significantly improved the outcomes of cancer patients in real-world medical practice. 

Limitations of Animal Models 

• Species differences: There are significant biological differences between animals and humans. These differences can lead to misleading results, with drugs that work in animals failing in human clinical trials. According to the NIH, the translation of drugs from animal testing to human therapies has consistently faced a failure rate exceeding 92% throughout the past few decades. 
• Ethical concerns: Engaging in research that involves animals raises ethical considerations related to animal welfare, resulting in the implementation of regulations and increased oversight. These concerns stem from the well-being of animals and the challenges of extrapolating data from animals to humans, which has led to opposition against animal research. To address these issues, ethical committees have embraced the Four R’s Principles — reduction, refinement, replacement, and responsibility — as guidelines when making determinations regarding the use of animals in research. 
• High costs: Maintaining and conducting experiments on animals can be expensive, with considerable costs associated with animal care, housing, and experimentation. For instance, examining cancer therapeutics through rodent testing extends drug development by approximately 4–5 years and incurs expenses ranging from $2–4 million. In contrast to the cost of in vitro testing, animal experiments can be roughly 1.5–30+ times more expensive. 
• Limited human relevance: Animal models are highly valuable for research but may not always accurately represent human biology, particularly in diseases with species-specific characteristics. For example, in Alzheimer's disease research, transgenic mice are commonly used, but they do not naturally develop Alzheimer's like humans, leading to potential disparities in disease mechanisms. This emphasizes the need to complement animal models with other research approaches. 

Comparative Analysis 

Because organ-on-a-chip models are designed to closely mimic human physiology, using human cells and tissues, this human relevance is a significant advantage over animal models, which have inherent species differences that can limit the translation of research findings to humans. 

In recent years, ethical concerns surrounding the use of animals in research have intensified; however, organ-on-a-chip models offer a more ethically sound alternative, reducing the need for animal testing and aligning with growing societal concerns. 

While animal models allow studying complex interactions within a whole organism, organ-on-a-chip models focus on individual organs or specific functions. Choosing between these two methods depends on the research goals, as organ-on-a-chip models may be suitable for targeted studies, while animal models provide a broader perspective. 

Organ-on-a-chip models have higher initial setup costs but can offer cost savings in the long run due to their potential for high-throughput screening and reduced reliance on animal models. Researchers should consider the overall budget and timeline when deciding which approach to use. 

Animal models have historically provided a more straightforward path for translating research findings into clinical applications. However, as organ-on-a-chip models become more sophisticated and widely adopted, their translational potential also increases. 

In healthcare technology research, organ-on-a-chip and animal models have distinct roles and advantages. Researchers must carefully consider their research goals, ethical concerns, budget constraints, and each approach's benefits and limitations. While organ-on-a-chip models offer promising opportunities to advance precision medicine and reduce the reliance on animal testing, animal models continue to provide valuable insights into complex whole-body interactions. Ultimately, the choice between these two methods should be made strategically, focusing on advancing medical knowledge and improving patient care while respecting ethical considerations.