Novel SERS-active optical fibers prepared by the immobilization of silver colloidal particles

A novel sensor based upon surface-enhanced Raman scattering (SERS) has been constructed by immobilizing colloidal silver particles onto the distal end of an optical fiber. This same single fiber was then used to both transpor t the exciting laser radiation and collect the Raman scattering from analyt es sorbed onto the colloidal particles. The colloidal particles were immobi lized by functionalization of the end of the optical fiber with (3-aminopro pyl)trimethoxysilane prior to immersion of the fiber in silver colloid. Spe ctra were obtained from both 4-(5'-azobenzotriazol)3,5-dimethoxy phenylamin e and crystal violet. The within-batch variation of a set of five fibers ha s been measured as approximately 10%. Raman imaging experiments demonstrate d that the effects due to spatial variations in the intensity of the SERS r ecorded ol er the distal end of the fiber are removed by the use of a multi mode fiber.