Etched and DNA coated Fiber Bragg Grating based biosensor for protein concentration measurement

In this paper, we propose a novel method for measuring the concentration of the protein (Bovine Serum Albumin-BSA) present in bio-chemical samples. The bio-sensor exploits the inherent characteristics of the Fiber Bragg Grating (FBG) which is coated with a biopolymer-namely, deoxyribonucleic acid (DNA). For increased sensitivity, the FBG was etched with hydrofluoric acid (HF) prior to coating with the DNA. The etched FBGs are sensitive to an external analyte by evanescent field interaction. The sensing mechanism is based on the interaction of the protein with the biopolymer film, which changes the film refractive index and also exerts some stress on the underlying fiber, resulting in a shift in the Bragg wavelength. By analyzing the Bragg wavelength shift, we can calculate the amount of protein present in the sample solutions. A complete experimental analysis, based on the use of an etched and coated FBG for protein concentration measurement, is presented.