Highly specific detection of interleukin-6 (IL-6) protein using combination tapered fiber-optic biosensor dip-probe.

We are reporting highly specific and sensitive detection of human interleukin-6 (IL-6) protein using combination tapered fiber-optic biosensor (CTFOB) dip-probe. With these probes we could successfully detect IL-6, down to a concentration of 5 pM (0.12 ng/ml) in the presence of much higher concentration of a non specific protein. Sandwich immunoassay was used to generate specific fluorescence signal. A novel strategy is developed to eliminate the false signal from non specific binding. In this new strategy it is not required to pre-treat probe surface with any kind of blocking buffer. The specificity of the sensor was established by incubating negative control probes in high concentration (1 nM) of another cytokine IL-8.