Public Summary Bram Kok

Imagine a chip that can measure important substances in the blood circulation in real-time! My Engineering Doctorate project focused on the research, development, and optimisation of an interleukin-6 (IL-6) biosensor chip, with the aim of making it applicable to a sensor. The ultimate goal was to create a chip that could be used in a sensor capable of measuring the health of fish in real time, without disturbing their natural behaviour. This turned out to be an ambitious challenge that required knowledge from many different fields. It required knowledge from optics and materials science to chemistry and biology, and involved creating a close collaboration between different departments of Wageningen University & Research and the University of Twente.

The project was based on an existing human IL-6 sensor that worked in a laboratory setting but with components that were not suitable for integration on a chip. Also, the sensor was not able to measure relevant concentrations. My task was to redesign it into a compact and potentially fully integrable system and to improve its detection limits. This meant rethinking both the optical design and the surface chemistry, while also thinking about how to apply it in the unknown underwater world of fish.

One of the main achievements of the research was the new optical design, which allowed the chip to operate with a simple, fixed laser source instead of a complex and expensive tuneable one. This makes the system smaller, cheaper, and more practical for integration into a complete sensor. Another major innovation was achieved in the field of surface chemistry. The original sensor relied on a commercial coating, of which the understanding was limited. To overcome this, we developed a new, tailor made polymer brush coating that could be grown directly on the chip surface. This coating offered better control, and brought the biological recognition layer closer to the optical waveguides, improving the sensor’s potential sensitivity.

Throughout the project, I learned that engineering research is rarely a straight path. It involves experimenting, iterating, and finding creative solutions when things do not go as expected. This EngD project truly reflected the essence of engineering: bringing complex, scientific principles together into something practical. It required me to balance between different disciplines, and to collaborate with experts from various backgrounds.

Although the chip has not yet been produced, the new chip design forms a strong foundation for future biosensing systems. Beyond the technical innovation, the project also has a clear societal relevance. By enabling continuous monitoring of fish health, this technology supports better animal welfare, sustainable aquaculture, and more ethical research practices.

The work combined design, experimentation, collaboration, and illustrates how design can be guided by an end product in mind. And how interdisciplinary teamwork can come together in one coherent and impactful project. That combination of technical innovation, interdisciplinary collaboration, and societal impact captures the spirit of the Engineering Doctorate, and makes this work a strong and fitting candidate for the KIVI Prize.