Synthesis and photo-thermal property of alginate/gold nanorod composite spheres

Abstract

Gold nanorods (GNRs) have received considerable attention in the development of novel photo-thermal materials because of their unique optical property. In this paper, alginate/GNR composite microspheres were synthesized through emulsification of the aqueous alginate/GNR mixture in the paraffin oil via a water/oil emulsion technique followed by cross-linking process in the solution of CaCl2. Microstructure and near-infrared (NIR) responsive photo-thermal property of the resultant composite spheres were investigated. SEM observations showed that the composite spheres were spherical in morphology and had the diameter of 5-40 μm. XRD patterns showed that the typical diffraction bands of GNRs were observed at 38° and 44° in the composite spheres. Under the 808 nm-NIR irradiation, the composite spheres were NIR-responsive and the temperature of the aqueous suspension of the composite spheres increased from 28°C to 39°C. It was found that their photo-thermal property could be well adjusted through controlling the content of GNRs in the composite spheres and irradiation time.