Use of animal models/samples before these samples are replaced with organ-chips:
Materials
While the actual experiment does not test the toxicity of the artificial blood substitute directly in animals, the experiment utilizes rat tail collagen to form the collagen matrix through which we intend to embed the cells, which could bring into question the harm done to the rats in the collagen harvesting procedures.
Artificial Blood Substitute
The artificial blood substitute (ABS) in the experiment will utilize bovine hemoglobin. Ethical considerations could include where the hemoglobin, and the cows that it came from, were sourced and the process through which it was obtained.
Mechanical Testing for Hydrogel Composition
To determine appropriate mechanical parameters for the collagen gel matrix such that it simulates in vivo conditions, tissues (heart, blood vessels, liver, etc.) may have to be harvested (requires killing a rat) to perform mechanical testing. Alternatively, reviews in literature may be used, but these would have to have been obtained by similar methods.