Detection of antinuclear antibodies by a colloidal gold modified optical fiber: comparison with ELISA.

A fiberoptic evanescent-wave sensor has been developed for the measurement of antinuclear antibodies in sera from patients and healthy individuals. The sensor was constructed on the basis of modification of the unclad portion of an optical fiber with self-assembled gold colloids, where the colloidal gold surface was further functionalized with extractable nuclear antigens. Results show that detection of antinuclear antibodies by this sensor agrees quantitatively with the clinically accepted enzyme-linked immunosorbent assay (ELISA) method. This sensing platform has the following advantages: label-free and real-time detection capability, simple to construct and use, highly sensitive, and does not require a secondary antibody. The sensitivity of this platform is at least an order of magnitude higher than that of the ELISA method and thus may lead to a new direction in recognition of immune response.