Tilted Fiber Grating Based Surface Plasmon Resonance Biosensor

Fiber optic biosensors are involved in many fields such as modern biotechnology,chemistry,optics and so on.They have a wide range of applications in the fields of food,drug inspection,and have great potential in medical research and clinical diagnosis.Therefore,in recent years,fiber optic biosensors has become a research hotspot.In fiber optic biosensors,tilted fiber grating based surface plasma resonance biosensors are of great concern for their high sensitivity and stability.A tilted fiber grating based surface plasma resonance biosensors relies on the surface plasma wave propagating at the interface between the metal and the dielectric,based on the sensitivity of the refractive index of the fiber surface,combining with the specific modification or other means to detect the biological,medical,or chemical samples.This paper based on the tilted fiber grating based surface plasma resonance biosensors,introduces its sensing principle and detection method,and on the basis of it,develops a new biosensor that combines the localized surface Plasmon resonance and a reflective biosensor.And use these two biosensors to detect the thrombin and the urine aquaporin2.This article introduces the following two experiments:(1)The experiment of the detection of thrombin.The thrombin detection experiment was carried out by using a localized surface plasmon resonance combined with surface plasmon resonance tilted fiber grating biosensor.The surface plasmon resonance was excited by sputtering uniform gold film on the surface of the fiber grating.After the specific modification of the biologically sensitive membrane,the modified biosensor is used to do the thrombin detection experiment,and then biosensor was modified with gold nanoparticles to achieve sensitizing effect.The innovation of this experiment is that the modification of gold nanoparticles,the biosensor already been used to detect the thrombin was modified with gold nanoparticles,so that the surface plasmon resonance can stimulate the localized surface plasmon resonance and increase the sensor detection limit.Experiment results show that the use of this sensor can successfully detect thrombin,identify thrombin concentration,and can effectively increase the detection limit by 3 orders of magnitude based on the surface Plasmon resonance tilted fiber grating biosensor.This experiment applys new ideas and new methods for biological detection,and also has a certain value in the field of clinical treatment and research;(2)The experiment of the detection of aquaporin-2(AQP2).The mice urinary AQP2 measurement experiment was conducted using a reflective surface plasmon resonance tilted fiber grating biosensor.Firstly,the relationship between nephrotic syndrome and abnormal AQP2 concentration is introduced,and it can be used to identify whether the kidney is suffering from nephrotic syndrome by measuring the concentration of urinary AQP2.Secondly,the sensing principle and the fabrication processes of the biosensor-the reflective surface plasmon resonance tilted fiber grating biosensor used in this experiment are introduced.Finally,the experimental steps and experimental results are introduced.The innovation of this experiment has two points,one is achieving the specific detection of the target through the surface plasmon resonance;The other one is achieving the reflective sensor structure,of which the sensor probe length is only 4-5 cm and the diameter is only 125?m,leading to a further miniaturization trend of the sensor.This experiment successfully modified the biologically sensitive membrane on the biosensor to achieve the specificity detection of AQP2 with a limit of detection of 1.5ng/ml.The study of this experiment will help to explore the possibility of rapid assessment of kidney disease and painless and effective treatment of kidney disease,has the potential for clinical diagnosis of human kidney disease.Since the sensor is operating in a reflective state,it has the potential for in vivo measurements.