Self-referencing fiber optic particle plasmon resonance sensing system for real-time biological monitoring.

We present the design and experimental verification of a self-referencing dual-channel fiber optic particle plasmon resonance (FOPPR) sensing system for compensation of thermal and bulk-composition effects as well as nonspecific adsorption in real-time biosensing of complex samples. A theoretical model is first proposed and then a systematic experimental approach is used to verify the model. The sensing system comprises an analysis fiber sensor and a reference fiber sensor in a single microfluidic chip, where the analysis fiber is functionalized with a recognition molecule. The compensation still works even if the surface coverages of gold nanoparticles on the reference and analysis fibers are not exactly the same. The potential of this approach is illustrated by a model biosensing experiment in which the detection of anti-biotin is compensated for bulk refractive index change, nonspecific adsorption and/or color interference, in various sample media. The percent recovery is 103.2% under both the effects of bulk refractive index change and nonspecific adsorption and is 93.9% under both the effects of color interference and nonspecific adsorption, suggesting that the compensation is effective.