Exploring multi-functionality in biologicallyinspired design through systematic development of medical equipment supporting corneal transplantation research

This PhD thesis focuses on the analysis of relationships between a technical problem’s functions and solution principles and is conducted in the intersection of biologically-inspired design research, engineering design research and medical research. Biologically-inspired design is a design process facilitating the adoption of inspiration from biological phenomena to synthesize novel technical products, whereby it belongs to the conceptual design phase of engineering design dealing with idea generation.

Current methods and tools assisting designers in biologically-inspired design practice rely on analyzing a technical problem’s functions in a hierarchical and sequential way resulting in array of required functions for which biologically-inspired design search procedures are conducted iteratively and solution synthesis is done by integration of single-functional solution principles inspired by biology. In contrast, nature contains a multitude biological phenomena with integrated multi-functional solution principles (just think of the mosquito trunk’s ability to support puncturing, movement and aspiration) corresponding too many functions at once. Additionally, researchers within the biologically-inspired design area recommend to search for multi-functional biological phenomena, although no specific support is available.

As the PhD project is conducted in an interdisciplinary collaboration between engineering design researchers in at DTU Mechanical Engineering and medical researchers at the University Hospital of Copenhagen, a medical equipment development project is conducted to provide theoretical and practical insights for the PhD project’s research. More specifically, an ex-vivo model of the anterior eye chamber is developed to serve medical research needs in relation to conducting basic cornea research and as a case example benefitting from the adoption of multi-functional solution principles serving the needs of the research areas biologically-inspired design and engineering design. Thus, the PhD project investigates the topic multi-functionality in biologically-inspired design with two main objectives: The development of an anterior chamber ex-vivo model supporting corneal transplantation research and synthesis of design support facilitating inspiration adoption from multi-functional biological phenomena.

In this context, an anterior chamber ex-vivo model is developed with systematic design methods from engineering design allowing the introduction of sub systems accommodating the required functions fundamentally different compared to the available of-the-shelf medical equipment. Additionally, the model is validated functionally and morphologically as central corneal thickness of different cornea tissue types are maintained within the physiological interval (450 μm – 550 μm) in a series of experiments simulating anterior chamber physiology for a maximum of 6 days with the model. Future research efforts are focused on cellular validation of the model, whereby basic cornea research are extended to corneal transplantation research allowing for studying the entirety of the post-operative phase after different corneal transplantations and the development of new surgical approaches improving patient care.

Finally, the Functions/Means/Relationships-tree is synthesized as design support for inspiration adoption from multi-functional biological phenomena based on existing literature on function modelling and functional reasoning, whereby structural relationships are introduced to handle relationships amongst solution principles of a product. This design support is successfully evaluated with respect to its application where respectively 64.3% and 50% of groups address two key factors related to the design support measurable success factor correctly, ultimately resulting in an increase of the relative amount of discovered multi-functional biological phenomena from 3.1% to 6.6% with the design support.