A flexible fiber probe for surface-enhanced Raman scattering (SERS) measurement was developed for performing an extremely sensitive Raman analysis for biomedical applications. The Raman probe consists of a ball lens mounted on a hollow optical fiber and allows Raman signals to be measured by a contact mode. Gold (Au) nanoparticles were placed on the ball lens by a dip-and-dry method. The increase in the background noise due to the deposition of the Au nanocolloids was very small. By using this new SERS probe, a Raman spectrum of 5% gelatin aqueous solution was successfully measured. A strong SERS signal was observed for the gelatin molecule in the solution. In particular, a C-S stretching band at 732 cm <sup>−1</sup> due to methionine residues, which could not be observed by an ordinary Raman microscope system, was observed clearly. The content of methionine was less than 1% in the gelatin molecule. The results show that this SERS probe has very high sensitivity and holds considerable promise in the applications of SERS spectroscopy for direct diagnosis of cancer tissues.
Vol. 7, Iss. 11 Virtual Journal for Biomedical Optics
Toshiaki Suzuki, Yasutaka Kitahama, Yuji Matsuura, Yukihiro Ozaki, and Hidetoshi Sato, "Development of a Flexible Fiber Surface-Enhanced Raman Scattering (SERS) Probe Using a Hollow Optical Fiber and Gold Nanoparticles," Appl. Spectrosc. 66, 1022-1026 (2012)