摘要： [Display omitted] ► Au nanorodSiO2 Raman tags were fabricated by optimizing surfactant concentration. ► A model is proposed for the mechanism of the direct silica coating on Au nanorod. ► Shorter time is required for the silica coating process. ► Au nanorodSiO2 Raman tags show comparable signals to the nanoaggregate tags. The applications of colloidal gold nanorods (AuNRs) as substrate for surface-enhanced Raman scattering (SERS) inevitably have to deal with a bilayer of cetyltrimethylammonium bromide (CTAB) around the AuNR surface. Here, we report an improved fabrication of silica-coated gold nanorods as SERS tags by mainly controlling the amount of CTAB to facilitate the synthesis. CTAB molecules on AuNRs were partially removed by centrifugation twice to allow the adsorption of Raman marker molecules and were re-added to promote the growth of silica shells. The zeta potential was used to monitor the charge state of AuNRs during the synthesis. A model of the morphology changes of CTAB assemblies is proposed based on the measurement of zeta potential and effects of pH value and CTAB/TEOS molar ratio. SERS tags with single AuNR enclosed in a round and 40nm-thick silica shell were produced within 24h. The SERS signal of a thus-prepared tag was compared with that of a nanoaggregate tag by a model probe–target system made of a biotin-functionalized polystyrene (PS) microsphere. Results showed that the SERS signal from the streptavidin-functionalized AuNR tag on a single PS microsphere is comparable to that from the nanoaggregate-tag counterpart. 出版者： Elsevier B.V 出版日期： 2012-09-05 出處： Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2012-09, Vol.409, p.61-68 版權： 2012 Elsevier B.V. 識別號： ISSN: 0927-7757 識別號： EISSN: 1873-4359 識別號： DOI: 10.1016/j.colsurfa.2012.06.003
