Development of fiber type surface plasmon resonance sensor for protein detection

As the mapping of the human genome has been completed, increasing emphasis is being placed on large-scale protein separation and identification methods to define the function of proteins and their associated genes. Within the last decade the sensing technique using surface plasmon resonance(SPR) has received a great deal of attention and has become a leading technology for affinity-based biosensing. In this paper I report a novel design of SPR fiber optic sensing elements which allows developing highly miniaturized SPR probes. A fiber-optic chemical sensor is presented which utilizes surface plasmon resonance excitation. The sensing element of the fiber has been made by removing a section of the fiber cladding and symmetrically depositing a thin layer of highly reflecting metal onto the fiber core. A white light source is used to introduce a range of wavelengths into the fiber optic. Changes in the sensed parameters are determined by measuring the transmitted spectral intensity distribution. Therefore, when a protein layer is adsorbed on the metal surface, an increment in the refractive index occurs and can be detected. Based on theoretical analysis, the sensor structure is optimized to achieve the maximum sensitivity.