Biosynthesis of Gold Nanoparticles Using Osmundaria Obtusiloba Extract and their Potential Use in Optical Sensing Applications

L. Adorno, A. Rojas-Pérez, MdM. Cordero, A. Ruiz, Z. Mercado, A. Rodríguez, L. Betancourt, C. Vélez, I. Feliciano, C. Cabrera, L. Díaz-Vázquez
University of Puerto Rico, Río Piedras Campus,
Puerto Rico

Keywords: gold nanoparticles, biosynthesis, Osmundaria obtusiloba, SERS, fluorescence enhancement and quenching, colorimetric analysis, electrochemical sensing

Summary:

The optical properties of gold nanoparticles depend on particles size, shape, protective ligand and the synthesis method used for their production. The present study describes an eco-friendly method for the synthesis of gold nanoparticles (AuNPs) the macroalgae Osmundaria Obtusiloba. The optical properties of the obtained nanoparticles and whether the use of the macroalgae extract confers them with additional properties were evaluated and compared with NPs obtained via traditional methods. The formation of AuNPs was confirmed by the presence of an absorption peak at 540 nm using UV-VIS spectrophotometry and was observed within 10 min. Au NPs were physical and chemically characterized by FTIR, TEM, SEM-EDS and XRD. TEM images reveled several shapes including spherical, triangular and diamond shaped nanoparticles with size ranges between 10 to 20 nm. XRD pattern confirmed that nanoparticles have a face centered cubic (fcc) crystalline structure. The presence of 83.58 %wt. of elemental gold in the obtained nanoparticles was confirmed by EDS. As well the utility of the generated gold nanoparticles for fluorescence was evaluated using methyl orange