Electrical properties of R-phycoerythrin containing Ag0 nanoparticles in its channels

Abstract

The electrical properties of R-phycoerythrin modified with Ag⁰ nanoparticles (Ag⁰ • R-PE) as a candidate material for biosensors were studied were studied. Modification was ensured by a known procedure: synthesis of Ag⁰ nanoparticles in R-phycoerythrin channels through the addition of AgNO₃ to an aqueous R-phycoerythrin solution. According to electron microscopy results, the Ag⁰ • R-PE contains predominantly elongated Ag⁰ nanoparticles 6.2 ± 0.5 nm in length, which form structures similar to rows 20–60 nm in length. The electrical conductivity, dielectric permittivity, and dielectric loss of the Ag⁰ • R-PE have been measured in the frequency range from 0.01 Hz to 1 MHz. Filling the channels in R-phycoerythrin molecules with Ag⁰ nanoparticles has been shown to increase the alternating current electrical conductivity and dielectric loss of the material at low frequencies by more than 200 times and its dielectric permittivity by 40 times. Ag⁰ nanoparticles increase the direct current conductivity of R-phycoerythrin from 5 × 10^–14 to 2.5 × 10^–11 S/cm. The electrical properties of Ag • R-PE are comparable to those of conductive polymer composites that contain metallic nanowires and are used in designing multifunctional films and smart materials.