Scientists have created fibre optic sensors which dissolve completely inside the body, and could be used for in-body monitoring of bone fracture healing and safer exploration of sensitive organs such as the brain. A fibre Bragg grating is an optical element inscribed in an optical fibre, which is widely used as a sensing instrument. The new glass fibres should be safe for patients even if they accidentally break, according to the study published in the journal Optics Letters. "Our work paves the way towards optical fibre sensors that can be safely inserted into the human body," said Maria Konstantaki from the Institute of Electronic Structure and Laser (IESL) of the Foundation of Research and Technology - Hellas (FORTH), Greece. "Because they dissolve, these sensors do not need to be removed after use and would enable new ways to perform efficient treatments and diagnoses in the body," said Konstantaki. The researchers show that gratings etched into the bioresorbable glass fibre dissolve under conditions simulating those of the human body. The new bioresorbable optical fibre Bragg gratings could be used to sense pressure at joints or act as tiny probes that can safely reach and assess the heart and other delicate organs. Laser-based techniques for removing tumours might also be improved with these optical fibre gratings, which could simultaneously deliver the laser beam and provide the accurate real-time temperature sensing necessary to monitor the laser ablation process. "This is the first time that a widely used and well-calibrated optical element such as a Bragg grating has been etched into a bioresorbable optical fibre," said Konstantaki. "Our approach could potentially be used to create various types of interconnected structures in or on bioresorbable optical fibres, allowing a wide range of sensing and biochemical analysis techniques to be performed inside the body," said Konstantaki.
