Medical biotechnology aims to use cells, tissues, or biological materials to create pharmaceuticals, diagnostics, and therapies that prevent or treat human disease.
To do this, we need model systems — simplified versions of biological reality that let us ask controlled scientific questions.
A perfect model system = a perfect snowman:
But in practice, we often get the lumpy snowman:
This frames the core challenge: 👉 We want models that resemble human biology enough to be meaningful, while still being ethical, accessible, and experimentally tractable.
The lecture walks through the continuum from simple to complex:
Placed toward the human end of the spectrum — but not quite “human physiology.” They mimic specific aspects of an organ, not the whole human organism.
Organoids are 3D multicellular structures grown from stem cells that self-organize into miniature versions of organs.
Take a biopsy → isolate adult stem cells → embed in extracellular matrix → expand.
Pros:
Cons:
Start from pluripotent stem cells → direct them with growth factors → form germ layers → differentiate.
Pros:
Cons:
The lecture centers heavily on the first major breakthrough: the 2009 Sato et al. paper.
Scientists figured out how to keep intestinal stem cells “happy,” dividing, and differentiating in 3D culture.
If you provide the right signals, a single intestinal stem cell will:
This proved that stem cells carry intrinsic spatial information:
They “know” what tissue architecture should look like, even outside the body.
Organoids need a scaffold to grow in.
For clinical use, we need fully defined, reproducible biomaterials → one of the engineering challenges.
Intestinal organoids form crypts and villus-like buds because:
This is a core concept: 👉 Organoids recapitulate key functional and architectural features of real organs, even without external patterning.
The lecture distinguishes between:
This progression shows how mechanobiology, patterning, and tissue engineering move organoids closer to actual organs.
The lecture emphasizes a long list of applications:
Infectious diseases, metabolic diseases, genetic disorders, inflammation, regeneration, etc. Organoids allow controlled experiments on human tissue, which normally isn’t ethically possible.
Organoids help bridge the gap between:
Especially important for rare diseases where mouse models do not exist.
A landmark: 👉 In 2022 an organoid model was accepted as part of pre-clinical approval for drug testing (for CIDP-like neuropathy).
Heart organoids → cardiotoxicity Liver organoids → hepatotoxicity Intestinal organoids → absorption & barrier function
This reduces reliance on animal testing.
Tumors can be grown as tumor-derived organoids (TDOs):
Gut organoids + gut microbiota → controlled models of:
The long-term dream: 👉 Use organoids for organ replacement.
The lecture revisits the idea through animal studies:
Suggested a future with:
In inflammatory bowel disease (IBD):
This suggests: 👉 Chronic inflammation imprints long-lasting epigenetic changes on intestinal stem cells.
A major theoretical insight.
The lecture highlights the main theoretical limitations:
The field is rapidly evolving toward tissue engineering rather than pure stem cell biology.