Why it matters

Aging is a major underlying risk factor for numerous chronic and degenerative diseases. Rather than treating individual age-associated diseases independently, emerging strategies seek to understand and control the fundamental biological processes of aging and ultimately develop interventions that restore tissue function and promote rejuvenation.

However, human aging is particularly difficult to study experimentally. Animal models often fail to reproduce human-specific aging phenotypes because of interspecies differences, while conventional in vitro models cannot capture the progressive interactions among cellular dysfunction, tissue microenvironmental changes, vascular and immune alterations, and inter-organ communication that collectively drive systemic aging.

Why it matters

Cancer remains difficult to treat not only because of its genetic complexity but also because every patient's tumor exists within a distinct biological microenvironment.

Patient-derived tumor organoids preserve many genetic and phenotypic characteristics of individual tumors and have emerged as powerful tools for personalized drug testing. However, conventional tumor organoids primarily reproduce the cancer cells themselves and cannot fully reconstruct the tumor microenvironment (TME), including extracellular matrix, stromal and immune cells, vascular components, mechanical properties, oxygen gradients, and tissue-specific metastatic niches.

Moreover, metastasis—the major cause of cancer mortality—is a dynamic process involving interactions between cancer cells and multiple tissue environments that cannot be reproduced by tumor organoids alone.

​Why it matters

Drug safety assessment is undergoing a major transition from conventional animal testing toward human-relevant New Approach Methodologies (NAMs). This transition is particularly important for monoclonal antibodies and other immune-modulating biologics, for which species-specific immune responses substantially limit the predictive value of animal models.

Immunotherapies can induce complex and sometimes systemic adverse effects involving multiple organs. Reconstructing these responses requires experimental models that incorporate both human tissue-specific biology and functional immune components.

MPS technologies provide an opportunity to reproduce these human-specific interactions while enabling mechanistic investigation and quantitative toxicity assessment. Establishing standardized and reproducible human immune-MPS platforms will therefore be essential for their future implementation in regulatory drug development.

Why it matters

Tissue barriers such as the blood–brain barrier (BBB), intestinal epithelium, pulmonary barrier, and lymphatic endothelium tightly regulate molecular transport, creating major challenges for effective drug delivery. The BBB is particularly restrictive, preventing most macromolecular drugs and biologics from reaching the brain.

Conventional screening using simplified cell cultures or animal models often fails to predict human delivery because it cannot fully reproduce species-specific barrier biology and physiological factors such as shear stress, cellular polarity, intracellular trafficking, and multicellular interactions. Human MPS therefore provide a physiologically relevant platform for the function-based discovery of drug delivery systems directly within human tissue environments.