Silk Fibroin Diaphragm-based Fiber-tip Fabry-Perot Pressure Sensor

The demand for optical interfaces for biomedical applications has led to growing demand for development of biocompatible photonic components.Bio-photonic devices are necessary for some applications,including sensors,imaging,biomicroelectromechanical systems(MEMS)devices,and therapeutics,making them bridges between optics and biology world.Silk fibroin is widely used in biological field due to its good biocompatibility and adjustable biodegradability.Moreover,silk fibroin have great prospects in the field of optics because of its excellent optical properties.The application of silk fibroin in fiber-optic sensing has been explored in this thesis.The regeneration of silk fibroin aqueous solution is studied first in this thesis.As a natural polymer material,a prominent advantage of silk fibroin aqueous solution is its environmentally benign fabrication process.Moreover,although the fundamental structure of silk fibroin is quite simple,its secondary structure is complicated,which makes silk fibroin exhibit excellent optical and physicochemical properties,resulting in new possibilities as novel bio-photonic devices besides its conventional applications in biomedical field.Secondly,the fabrication of silk fibroin diaphragm-based fiber-tip Fabry-Perot sensor is studied.With proper choice of surface processing technique and fabrication technique of the sensor,regenerated silk fibroin aqueous solution can form silk fibroin film on one end of a fiber ferrule with good quality which results in a good Fabry-Perot cavity with a cleaved fiber end.A high quality interference spectrum of this silk fibroin diaphragm-based fiber-tip Fabry-Perot cavity is observed,which can be used as a Fabry-Perot sensor with excellent biocompatibility.Finally,based on a fiber ferrule and regenerated silk fibroin aqueous solution,a new biocompatible fiber-tip Fabry-Perot pressure sensor is proposed.It shows that the thickness of the silk fibroin film of this sensor is about 20?m.The sensor demonstrates a good linear response in a pressure range of 0~0.08 MPa.Demodulated by Fourier transform to find the relation between the cavity and the pressure,the proposed sensor exhibits a response of 12.3 nm/kPa in terms of cavity length variation.