Laws of optics for medical textiles
Engineers at the Massachusetts Institute of Technology (Massachusetts Institute of Technology) have developed light-sensitive fibers that are woven into the fabric of a compression bandage. When the bandage is stretched, the fibers change color. Using a color chart, the caregiver can stretch the bandage until it matches the color of the desired pressure, and then wrap it around the patient's leg.
Photonic fibers are made of ultra-thin rubber threads twisted to create a soft roll structure. Each layer in the roll is only a few hundred nanometers thick. Thanks to this swirling configuration, light is reflected from each layer. Depending on the thickness of the layers, the reflected rays interact to form colors in the visible spectrum. The color does not change as long as the roll structure is preserved.
The fiber design is based on interference, an optical phenomenon in which light reflected from thin transparent layers can create bright colors that depend on the geometric parameters of the surface and its composition.
The authors write that by changing the thickness of the fibers, they can create bandages with any color scheme, so that, for example, green means ideal pressure, and red means excessive.
Photonic fibers were woven into the fabric of a compression bandage. Using the relationship between the stretching and the pressure of the bandage, as well as between the color of the fiber and the tension, the scientists created a color diagram of the correspondence of the pressure generated by the bandage to the color of the fiber.
The development was tested on volunteer students who split into pairs and applied compression bandages to each other. Three types of bandages were used in the experiment: a conventional compression bandage, a bandage with photonic fibers and a bandage with a rectangular print (when properly stretched, rectangles turn into squares).
The bandage with interwoven photonic fibers provided the most accurate compression of the limb. The students were able to correctly interpret the color of the fibers and choose and create the optimal pressure based on the color chart.
Currently, researchers are studying the possibility of reducing the cost of photonic fibers. The high price for them is due not to the cost of the raw materials, but to the complex and expensive creation process. If they manage to develop a technology for creating meters or even kilometers of fiber in one cycle (now the maximum length is several tens of centimeters), then the price will immediately drop significantly.
After that, compression materials with photonic fibers can be widely implemented not only in clinical medicine, but also in the sports sector – they can be used for sewing sports uniforms and shoes or to assess the degree of muscle tension during exercise.
Article by J. D. Sandt et al. Stretchable Optomechanical Fiber Sensors for Pressure Determination in Compressive Medical Textiles is published in the journal Advanced Healthcare Materials.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of MIT News: Engineers design color-changing compression bandage.