Instrumentation Set-up using Surface Plasmon Resonance for Dielectric Based Sensing in Biological Applications

摘要

Surface Plasmon Resonance (SPR) is an important Optical Bio-sensing instrument. It plays a vital role in the medical, biological, laboratory research and pollution detections. SPR become a predominant tool because of its instantaneous and real time detection of molecular changes. There are few SPR instrument manufactures in all around the world and the instrument is also very cost expensive for the purchase. In development of such an instrument (SPR) at affordable cost is important and it will be helpful for the human society. With this intention the work is carried out and SPR Prototype is developed based on kretschmen configuration. Based on the kretschmen configuration, the He-Ne laser beam is directed through the BK-7 Prism, over which the gold coated glass plate and dielectric sample is kept in adjacent. All these optical arrangements are kept over the Stepper motor, which is stage controlled back and forth by programmed PIC 18F2550 microcontroller. At an angle greater than critical angle, the TIR occurs and the major amount of laser beam is reflected back and a small portion of light is gets absorbed by molecules and generated as SPR, which is measured by Photo Voltaic cell or a Light Dependent Resistor, whose results are discussed. The generated SPR is measured in real time through USB port to the computer through Programmed PIC 18F2550&VB Program. Thus, the SPR prototype was developed and the instantaneous molecular changes are plotted between the reflection and theta in real time from the SPR Instrument USB to the Computer through PIC 18F2550 microcontroller and Visual Basic programming.