Design of an implantable biosensor for real-time in vivo measurements in aquatic organisms

This study explored the development of a human interleukin-6 (IL-6) biosensor chip. First, the key limitations of a previously developed IL-6 biosensor are discussed: the lack of possible integration of optical components on the chip and insufficient understanding of the commercial hydrogel utilized for antigen binding. Therefore, the optical circuit was redesigned with an asymmetric Mach-Zehnder interferometer, which allowed the use of a laser source at a single wavelength. Additionally, polymer brushes were synthesized directly on the surface of the chip, providing more understanding of, and control over, the selective antifouling layer. Experiments indicated that the asymmetric Mach-Zehnder interferometer could detect human IL-6 concentrations as low as 0.8 ng mL-1. Follow-up experiments are recommended to explore the full potential of the chip. This thesis paves the way for further research with the biosensor chip and lays a solid foundation for expanding its functionality towards an implantable biosensor.