Fraunhofer Institute for Applied Polymer Research
Fraunhofer Institute for Applied Polymer Research

Mechanochromic sensor sole based on 3D-printed TPU to detect pressure on the foot

In order to prevent ulcers and inflammation in diabetic feet, mechanochromic sensor material for shoe soles is to be developed as part of the FootPrint project. This allows critical pressure distribution to be indicated by a change in colour and this can be recorded electronically.

Printable mechanochromic insole for patients with diabetes

Technical demand:

  • Visualisation of the accumulated pressure distribution
  • Early detection of incorrect loads
  • 4D mapping of foot topology as a basis for data science
  • Individualised medical support based on accumulated data
  • Prediction of the development of the clinical picture

 

 

 

 

 

 

 

 

Scientific-technical solution:

  • Visualisation of the accumulated pressure distributions
  • Colour-force correlation
  • Machine-readable colour distribution 
  • Individualisation through additive manufacturing processes and adaptive shapeability
  • No external energy source
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  • A common side effect of diabetes is the loss of nerve function in the extremities. Poorly fitting footwear is often the cause of the additional deterioration in blood circulation. As a result, inflammation occurs which the affected person hardly notices. This in turn leads to poorly healing ulcers, which are the cause of around 70% of amputations. Special diabetic insoles are designed to prevent this. These are customised and have to be adjusted regularly at great expense. Due to their high price and limited availability, electronic sensor soles are not an alternative to the desired solution.

     

    In the "FootPrint" project, a colour-changing sole is being developed on the basis of 3D-printed elastomers. Over time, an intuitive colour change indicates critical pressure distributions before they lead to side effects. At the same time, the colour topology of the sole enables patients and therapists to react in a targeted manner. Over time, such a sole can also generate topological data that can be recorded visually and electronically, enabling the production of customised soles for the patient and also making the development of the footbed predictable.

  • Funding

    This project is funded as part of the Fraunhofer-Gesellschaft's internal programmes.