Human Immunoglobulin Class G (IgG) Antibody Detection With Photonic Crystal Fiber

Dye-free antibodies were identified in a less than 5-nL volume with a solid-core photonic crystal fiber (SC-PCF). The all-silica fiber contained micrometer-sized features with a 3-μm diameter core supported by a steering wheel-shaped lattice. These structures can be employed to monitor the presence of immunobased assays and susceptible secondary antigens specific to the detection application. A 0.8-m section of SC-PCF was filled with a 4.47-nL antibody sample and a LED light source in the 1300-1700 nm range was employed. Although similar sensing configurations exist, the novelty of this investigation is the detection of this particular antibody. This experiment uniquely investigates the spectral characteristics of purified human immunoglobulin class G (IgG) (format-UNLB) in aqueous media. The absorption spectra for the monoclonal antibodies were collected with a conventional optical spectrum analyzer. The antibody solution exhibited two distinct absorption peaks, a water-linked absorption peak between 1400 and 1470 nm, with a maximum absorption power of 1.65 nW, and an antibody-linked absorption peak between 1485 and 1590 nm, with a maximum absorption power of 3.2 nW.