Measurements & Analysis
For tissue engineering, a few key measurements are needed to identify whether a material is correct for the right application. The three most important things are cells, scaffolds, and growth factors (Guerrero-Aspizua, 2016). Various measurements help to find these three properties. First, researchers must know the biocompatibility, immunogenicity, antigenicity, toxicity, and other biological properties (degradability, etc.) of their materials; if they are not suitable for implantation in the human body, either they must be made suitable or they cannot be used. Second, researchers must know the mechanical properties of the material, to make sure that it will be able to withstand loads and best match the needs for each application. For example, skin must be stretchy and strong, resistant to multiple climates. Hearts must be smooth and elastic, resistant to strain/loads but still able to move easily. Some materials must be porous. Etc. Third and finally, the researchers must know how the material will interact with other materials in the structure; e.g. compatibility between scaffolding and additives is an absolute requirement. See table to follow for more information on what techniques are actually used to find these properties.
Collagen
Collagen is so common, that some of the most important things to know are: 1) what type of collagen you have in the first place; 2) what the macrostructure is for that type of collagen; and 3) what the typical strength is for that type of collagen. While it is a structural material, collagen is not especially well-known for its strength, therefore various the strength of the type of collagen must be known - identifying strain/stress is very important. Again, see the table for more information of techniques used to find these properties.
Elastin
In the analysis for elastin, something to focus on is its elastomeric qualities. Since it is traditionally a natural material, the closest that can be compared to is the ASTM standard for flexible materials such as sponges and rubber. While this testing is usually performed by testing large pieces of materials, typically small specimens, special testing needs to be done in order to test for consistent flexibility. These standards have several grades including compression and extension of the product. In the case of Type-1, open-cell rubber, with grade 0 able to handle a compression-deflection range of 0-2 psi. This would be the optimal space for elastin to be tested in small quantities (ASTM Compass 2021).
​
Elastin must also be tested for water content which can be done through weight and analysis of water within elastin crystals (Debelle & Alix 1999). The water content is important for the fact that water content is important in different types of organ scaffolding specifically in the skin and heart scaffolding where water content needs to be regulated in order for the organs to function properly. This is seen in the fact that collagen for skin needs to be pressed under a weight to make a dense layer for the dermis in the skin (UCL 2010).