Open Access Nano Express

Induced pH-dependent shift by local surface plasmon resonance in functionalized gold nanorods

Yon-Rui Toh1, Pyng Yu1*, Xiaoming Wen1, Jau Tang1* and Tao-shih Hsieh2

Author affiliations

1 Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan

2 Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan

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Citation and License

Nanoscale Research Letters 2013, 8:103  doi:10.1186/1556-276X-8-103

Published: 22 February 2013

Abstract

Localized surface plasmon resonance (LSPR) spectroscopy of metallic nanoparticles is a powerful tool for chemical and biological sensing experiments. In this study, we observed LSPR shifts of 11-mercaptoundecanoic acid modified gold nanorods (GNR-MUA) for the pH range of 6.41 to 8.88. We proposed a mechanism involving changes of the dipole moment after protonation/deprotonation carboxylic groups of 11-mercaptoundecanoic acid (MUA) which plays an important role by modulating LSPR around the functionalized GNR. Such a stable and easily prepared GNR-MUA has potential to become one of the most efficient and promising pH nanosensors to study intra- or extra-cellular pH in a wide range of chemical or biological systems.

Keywords:
Gold nanorods; pH sensor; LSPR; 11-mercaptoundecanoic acid