Axonic Au Tips Induced Enhancement in Raman Spectra and Biomolecular Sensing

作者：Saini Apurve; Medwal Rohit; Bedi Saurabh; Mehta Bharat; Gupta Rekha; Maurer Thomas; Plain Jerome; Annapoorni S^*

来源：Plasmonics, 2015, 10(3): 617-623.

DOI：10.1007/s11468-014-9847-4

• SERS
• ATR SPR
• Biosensor
• Stars
• Urea sensing

Axonic Au stars with sharp crystalline tips were synthesized via reduction of HAuCl4 capped with cetyl trimethylammonium bromide (CTAB). A seed-mediated method was adopted in which Au seeds were used in the growth solution containing Au+ ions, for initiating the nucleation with CTAB and with ascorbic acid acting as a mild reducing agent. Transmission Electron Microscopy image clearly reveals the synthesis of gold stars. The gold star dispersions display a well-defined optical response as observed by the presence of a sharp surface plasmon resonance centered at 525 nm. The Au stars functionalized with 11-mercaptoundecanoic acid and immobilized with urease showed improved urea-sensing behavior in comparison to pure gold disk in attenuated total reflection surface plasmon resonance (ATR SPR) mode. Surface-enhanced Raman spectroscopy performed using the functionalized Au stars showed a significant enhancement in Raman signals for a wider range of urea concentration (2-20 mg/ml).

• 出版日期2015-6