Optical fibres are widely used in industrial applications including sensing, imaging and treatment. However, optical sensors utilising solid-state materials (e.g., silica) are not fully compatible with biological systems for implantation in vivo. Solid-state optical fibers may cause infection and immune reactions (foreign body responses) at an implanted site, resulting in inflammation and discomfort to patients. This necessitates the development of biocompatible implantable biosensors. 

Image of optical fibre sensors showing light transmission

Unlike existing solid-state optical fibers, soft polymer and hydrogel fibers offer physical and chemical properties well suited for functionalization with biomolecules and long-term implantation into the body. We have demonstrated the functionalisation of hydrogel optical fibers with glucose-sensitive moieties. The biocompatible hydrogel fibers may be implanted in the body for continuous monitoring of interstitial glucose concentrations.