Intrinsic fluorescence, protein adsorption

Optical fibers without cladding can be used to monitor the adsorption of chemical species such as proteins on an optical Hber core [87]. Fluorescence is induced by the evanescent wave field of the light propagating in the core. For example, the intrinsic fluorescence of the amino acid tryptophan in immunoglobulin (IgG) and the fluorescence of fluorescein-labelled IgG were detected and used to calculate the amount of protein adsorbed on hydrophilic glass and quartz surfaces. Fluorescent, nonadsorbing dextran was used as a calibration molecule which approximates the diffusion properties of the protein. Remote spectroscopic sensing of the adsorption of Rhodamine B-labelled IgG at the tip of a 600-pm fiber optic has also been described [88, 89]. 

VanWagenen, R. A., Rockhold, S., Andrade, J. D., Probing Protein Adsorption Total Internal Reflection Intrinsic Fluorescence , in Interfacia Phenomena and Applications, Cooper, S. L., Pappas, N. A. (eds.) New York Wiley, 1982, p. 351. 

Total internal reflection intrinsic fluorescence (TIRIF) spectroscopy and molecular graphics have been applied to study the adsorption behavior of two lysozymes on a set of three model surfaces. A recently devised TIRIF quantitation scheme was used to determine adsorption isotherms of both hen egg-white lysozyme (HEWL) and human milk lysozyme on the three model surfaces. This preliminary study suggests that the adsorption properties of the two lysozymes are significantly different, and that further comparative studies of the two lysozymes might prove to be beneficial in understanding how protein structure might influence adsorption properties. Molecular graphics was used to rationalize the adsorption results from TIRIF in terms of the proteins surface hydrophobic/hydrophillic character. 

---