Protein adsorption using an evanescent chemical sensor with a fused optical fiber coupler

The utility of an evanescent fiber optic chemical sensor featuring a fused Y-type optical fiber coupler was investigated. The coupler was fabricated by fusing the tip of a 200-μm fiber to a 600-μm main sensing fiber equipped with an evanescent sensor tip. The probe was directly connected with a fiber optic spectrophotometer through a SMA connector. A linear dynamic range of three decades was observed from 10-7 to 10-4M with a detection limit of 10-8M. The detection limit and dynamic range of the sensor were independent of laser power, but lower laser power and shorter exposure time were desirable to minimize photobleaching effects. The response of the sensor to thin-layer samples was observed by monitoring protein adsorption onto the optical fiber surface using rhodamine B isothiocyanate labeled bovine serum albumin. Fit of the protein adsorption data to the Langmuir theory provided molar binding constants on the order of 10-1μM-1. © 1990.

Duke Scholars

Author William M. Reichert Biomedical Engineering