Research On Fiber Biochemical Sensing Technology Based On Surface Raman Spectroscopy

Recently,the biochemical terrorist attacks spread globally,and the food poisoning incidents occur frequently,which are caused by the toxic and harmful biological molecules.Therefore,it is of great significance to find fast and accurate method for detecting harmful biochemical molecules.There are two main methods of spectroscopy detection: mass spectrometry and spectrometry.The surface enhanced Raman scattering(SERS)sensing technology has the advantages of high sensitivity,good selectivity,and rapid detection,and has the function of molecular structure fingerprint,so SERS sensing technology show great potential applications in the field of photochemical sensors.Traditional SERS technology requires the production of metal micro-nanostructured substrates that deposited on the glass sheets and the Raman signal must be tested under the large Raman spectroscopy.The equipment is too bulky and expensive to meet the needs of field testing.The fiber has the advantages of low loss,anti-interference,low production cost and simple manufacturing.The SERS probe,which is prepared by depositing the noble metal micro/nanostructure on the surface of the fiber,can achieve the on-line monitoring and remote detection of the biochemical sample molecules while maintaining the sensitivity and rapid detection characteristics.Based on the optical theory and technology of fiber SERS probe,modern MEMS/NEMS technology and the urgent need of food safety detection,this paper researched the biochemical sensor technology of fiber probe that based on SERS effect,and deeply studied the design method of optical fiber probe.At last,two kinds of fiber SERS probes with high sensitivity and good stability were prepared.Using the prepared fiber SERS probe,the detection of rhodamine 6G(R6G)was successfully achieved.In this paper,the basic concept of surface-enhanced Raman scattering is introduced,and the basic working principle and the application field of fiber-optic biochemical sensor are discussed.Then,a kind of cone-cylinder combined fiber SERS probe is designed for the traditional SERS technique.The parameters of the SERS probe are optimized based on the ray tracing method.On this basis,the preparation technology of the SERS probe is studied emphatically,and the batch preparation of the SERS probe is realized.The paper then further investigated the effect of the different diameter of fiber probe cone column area as well as the modification time of silver nanoparticles on the detection performance of fiber SERS probe.The cone-cylinder combined fiber SERS sensor with speediness and high efficient were fabricated,and could be applied in fingerprint detection.The result showed that this kind of sensor could realize the rapid trace detection of R6 G molecules,and the detection limit was 10-14 mol/L.To solve the poor remote detection capability of the end-fiber SERS probe,the sensing technology of the fiber SERS probe based on the spherical surface was improved,and the geometric parameters of the spherical probe structure were optimized.The SERS activity of silver nanoparticles absorbed on the surface of fiber SERS probe was characterized.The fabrication of the spherical fiber SERS probe was developed by the fusion method as well as the silver sol self-assembly method,and successfully prepared the SERS probe sensitive structure.R6 G was applied as the object to investigate the performance of remote detection of the fiber ball that with different diameter.The result showed that the fabricated fiber probe could realize the fingerprint detection of R6 G molecules.Compared with the cone-cylinder combined fiber SERS probe,the probe is simple and safe,and the stability of the probe is further improved.It is verified that the fiber SERS probe sensor proposed here could realize the remote detection.