Enhancement of Fluorescence of Nanosized ZnO: SiO2 Films in the Presence of Human Serum Albumin

Abstract

The optical properties of the films of new nanosized of ZnO: SiO₂ materials with intense ultraviolet luminescence (UVL) with a maximum at 362 nm were studied. When human serum albumin (HSA) is applied on the surface of films, an effective fluorescent energy transfer occurs, which is manifested in an increase in the intensity of ultraviolet luminescence of ZnO: SiO₂. The increase in integrated UVL intensity is inversely proportional to HSA concentration; it has 9.2–12.6 times (with a decrease in the HSA concentration from 10^–8 to 10^–12 M) the UVL intensity of purified ZnO: SiO₂ film. The dependence of the UVL intensity on the HSA concentration is close to linear. Compared to the intensity at a concentration of 10–8 M, the gain is 8, 19, 31, and 36% for protein concentrations in the solution applied to the surface of ZnO: SiO₂ of 10^–9, 10^–10, 10^–11, and 10^–12 M, respectively. These supramolecular systems can be used to create biosensors and to simulate the physicochemical processes of photosynthesis. In the former case, the linear dependence of fluorescence on concentration is a significant advantage.