Рефрактометрический детектор белков плазмы крови на основе наклонной волоконной брэгговской решетки с функциональным покрытием из антител

Abstract

The article demonstrates the results of the development of a selective fiber optic biosensor based on tilted fiber Bragg grating. The underlying principle of the sensor involves shifts in the transmission spectrum of tilted grating, which transforms in accordance with the changes in the composition of the external environment. Optical signal propagating along the fiber couples with a tilted grating resulting in a number of cladding modes which form an evanescent field of the sensor directly interacting with the external environment. Potentially high sensitivity to the refractive index of the environment opens up prospects of using such structures as high-precision sensors of solution concentrations; however, for applications in the field of biomedicine, selective sensitivity is critically important, providing unambiguous detection of individual target components in a multicomponent composition. To ensure the selective sensitivity of the sensors presented in this work, functional coatings of antibodies against two types of human blood protein molecules were used in their design. The paper describes a technique for creating experimental samples of biosensors, involving inscription of fiber Bragg gratings and deposition of functional antibody-based coatings onto the surface of the fiber. Experimental results are presented highlighting problems occurring during detection with a single sensor. As a solution, the work proposes a differential measurement scheme involving two sensors modified against two different proteins. According to the results of studies during which fibrinogen and D-dimer were used as target proteins, the selective detection of the studied proteins in concentrations of up to 0.1 mg/ml is clearly demonstrated, which was achieved through the use of a differential measurement scheme.