Application of parylene film as a linker layer of SPR biosensor

Surface Plasmon resonance (SPR) biosensor has been applied for the on-line monitoring of a target analyte in complex mixture by using specific interaction between antigens and antibodies. In this work, mainly for reusability of SPR biochip, parlyene thin film was applied as a linker layer on gold surface of the SPR biochip. Parylene is a polymer of p-xylene with good optical properties, chemical resistance from organic solvents and relatively high mechanical strength which are required for the linker layer of SPR biosensor. The SPR effect is known to be the occurrence of an evanescence field by the absorption of incident light at the range of 100nm from the sensor surface and we tested the feasibility of parylene layer of less than 100nm as a linker layer by observation of resonance angle change according to refractive index. Parylene film can be easily coated and removed by oxygen plasma treatment so that SPR biochip can be used repeatedly. The applicability of the parylene film was demonstrated for the detection of C-reactive protein which is widely used to check for inflammation.