Label-free and sensitive detection of microalgae protein using GNRs-based resonance light scattering system

Abstract

A novel and label-free gold nanorods (GNRs)-based resonance light scattering system assay has been developed on the basis of that the interactions between microalgae proteins and GNRs could emit strong fluorescence signal. We have prepared GNRs which were well dispersed in the solution and the microalgae protein was absorbed onto the surface of GNRs. The results demonstrated that the intensity of fluorescence has correlation with the protein concentration. The optimum pH was 5.5 and the optimum concentration of inorganic salt ions Na⁺ was 0.5 mol L⁻¹; the stable time of the reaction system was 2 min. Because of the protein molecules are firmly combined with the surface of the gold particles, a protein layer is formed to prevent the aggregation of gold nanoparticles. Gold nanoparticles have a strong adsorption to proteins and other biological macromolecules and will not change their biological activity, hence it provides a number of advantages. This method offers the advantages of higher sensitivity and selectivity in microalgae protein detection and providing great potential for biology diagnosis.