It is difficult to say how the human skin precisely feels. For my research it is of importance though. I need to find out what part of it plays a role in the detection and treatment of hernia’s by physiotherapists. Does the resistance and feel of it play an important part? Or is only the structure and volume of interest? Describing the build-up of this haptic feedback in great details however, turns out to be quite difficult. Even while I am writing this, I am struggling for descriptive words. I do have to find out still how other researchers have tested this.
In essence when you touch your own body (especially the back), in its core it feels quite hard. The hardness however (caused by muscles [source?]) is topped by the skin. In between these two parts there is some slack. This slack is caused by the fact that the skin is not directly attached to the muscles but rather loosely lays on top of it [source?]. The skin itself feels quite rough and it is always a little fatty/moist.
So now, the question remains: how do we simulate this feeling in light of the proposed practicing apparatus? What is of importance to the practitioner and how do we imitate that feeling? This will be part of the research question.
For now I propose a stable base of Polystyrene Foam since it is an easily shape-able but quite stiff material, perfect for prototyping. This based would offer the overall shape and a space in the middle to attach the spine-device in it (see picture). The base would need holes for cross-fixing the spine and a hole at the underside to be able to run wires through. Next, the base would be covered with a gel of some sort. In this case I am proposing ballistic gel, since it it easy to make, stays well in shape and is often used to do penetration tests of bullets (and thus simulating the skin as well). It is made with the use of gelatine powder . (Will the gel melt back to liquid?). Lastly, we will need to cover the gel with an reproduction of a skin-like material. I am not sure yet what material this could be, and I would have to discuss it with therapists to find out how important the imitation needs to be. The gel-layer will make for the skin-layer to be able to move around like our own skin is.\
I will visit FormX in Amsterdam to get a realistic as possible replica of the human skin to put over my prototype. This will be part of the improvements for protoype 2.
Good article about synthetic skin
Dąbrowska, A. K., Rotaru, G. M., Derler, S., Spano, F., Camenzind, M., Annaheim, S., … & Rossi, R. M. (2016). Materials used to simulate physical properties of human skin. Skin Research and Technology, 22(1), 3-14. https://www.ncbi.nlm.nih.gov/pubmed/26096898
Halim, A. S., Khoo, T. L., & Yussof, S. J. M. (2010). Biologic and synthetic skin substitutes: An overview. Indian journal of plastic surgery: Official publication of the Association of Plastic Surgeons of India, 43(Suppl), S23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3038402/