Peculiarities of the Sensory Effect in the Structures “Prism–Gold Nanolayer–Protein Receptor”

Fragments of protein molecules are considered as sensitive elements of biosensors on surface plasmon resonance in the layered structure “prism–gold nanolayer–protein receptor”. Based on studies of protein molecules as channels of metabolic electron transfer, their specific conductivity was found. It is an important characteristic for modeling the sensory effect, as it directly determines the dielectric constant. And the change in dielectric constant directly determines the sensory effect. It is shown that the sensory effect depends weakly on the length of the protein chain, except for a narrow region from 16 to 48 amino acid residues. At lengths of < 16 amino acid residues, the conditions of surface plasmon resonance are not realized. In the region from 16 to 48 amino acid residues, the resonance wavelength increases rapidly from the near ultraviolet to the green range. When the number of amino acid residues exceeds 48, the wavelength of the plasmon resonance practically unchanged. Since natural proteins have much longer lengths, the change in the dielectric constant of protein receptors is largely unrelated to the change in their length. The effect of the refractive coefficient of the “input” prism on the resonance angle of incidence was also investigated. It is shown that preference should be given to prisms with large (~2) refractive coefficients.