Intracellular pH sensors based on surface-enhanced Raman scattering

Talley CE, Jusinski L, Hollars CW, Lane SM, Huser T. Intracellular pH sensors based on surface-enhanced Raman scattering. Analytical Chemistry. 2004;76(23):7064-7068.We present the development of nanoscale pH sensors based on functionalized silver nanoparticles and surface-enhanced Raman scattering (SERS). The SERS spectrum from individual silver nanoparticle (50-80 nm in diameter) clusters functionalized with 4-mercaptobenzoic acid shows a characteristic response to the pH of the surrounding solution and is sensitive to pH changes in the range of 6-8. Measurements from nanoparticles incorporated in living Chinese hamster ovary cells demonstrate that the nanoparticle sensors retain their robust signal and sensitivity to pH when incorporated into a cell