Yl. Wang et Dr. Bobbitt, BINDING CHARACTERISTICS OF AVIDIN AND SURFACE IMMOBILIZED OCTYLBIOTIN- IMPLICATIONS FOR THE DEVELOPMENT OF DYNAMICALLY MODIFIED OPTICAL-FIBER SENSORS, Analytica chimica acta, 298(1), 1994, pp. 105-112
Specific sensing ligands can be immobilized onto C-18,, derivatized op
tical fibers by a dynamic modification protocol as part of a general s
trategy for producing optical fiber sensors. To investigate the influe
nce of the hydrophobic surface and accessibility of the sensing ligand
on the binding characteristics of the ligand and target analyte, an o
ptical fiber sensor for fluorescently labeled avidin has been develope
d. Biotin's hydrophobicity is enhanced through the attachment of a C-8
moiety which allows it to be associated with the C-18 modified optica
l fiber surface through a hydrophobic interaction. Measurement of both
the time dependence and K-assoc for the binding of FITC-avidin to the
surface immobilized biotin show that the hydrophobic immobilization p
rocess decreases the binding strength relative to that observed in hom
ogeneous solution. When compared to previous studies in which a lipid-
derivatized biotin was associated in an LB film, the association const
ant is reduced by 2-3 orders-of-magnitude. These results, in combinati
on with the lipid-derivatized biotin/LB film studies suggest that spac
ers can be used to enhance the accessibility of the biotin moiety ther
eby leading to improved binding characteristics. This result has impor
tant implications for the design and development of dynamically modifi
ed, optical fiber sensors.