Raman spectroscopy for hydrogen peroxide scavenging activity assay using gold nanoshell precursor nanocomposites as SERS probes

Abstract

In this work, we have developed a novel SERS-based approach to detect hydrogen peroxide (H₂O₂) scavenging activity by using gold nanoshell precursor nanocomposites (SiO₂/GNPs) as nanoprobes. H₂O₂ can reduce AuCl₄⁻ to Au⁰ and enlarge the gold nanoparticles (GNPs) that attached on the surface of SiO₂. As the concentration of H₂O₂ increases, the surface coverage of resultant gold on silica cores increases accordingly until continuous gold nanoshells (GNSs) are formed. During the growth process, there is a strong correlation between the SERS-activity of the GNSs and the amount of H₂O₂ that is used as reductant. When H₂O₂ reaches 250 μM, the resultant GNSs show the highest SERS-activity. H₂O₂ can be scavenged by antioxidants such as tannic acid and L-apple acid. Their H₂O₂ scavenging activities were determined by restraining the H₂O₂-mediated (250 μM) growth of SiO₂/GNPs. The decrease of the SERS-activity was proportional to the H₂O₂ scavenging activity of the antioxidant. The results showed that tannic acid had a much higher H₂O₂ scavenging activity than that of L-apple acid.