Mapping Local pH in Live Cells Using Encapsulated Fluorescent SERS Nanotags


  • This work was supported by the Institute for Collaborative Biotechnologies through grant DAAD19-03-D-0004 from the U.S. Army Research Office and made extensive use of the MRL Central Facilities at UCSB supported by the National Science Foundation under award nos. DMR-0080034 and DMR-0216466 for the HRTEM/STEM microscopy. G.B.B. acknowledges a Corning Inc. Foundation Fellowship. A.P. thanks Antonella Motta (BIOtech lab, Univ. of Trento), Salvatore Iannotta (IFN-CNR Trento), and NANOSMART (Provincia Autonoma di Trento). A.P. and G.B.B. contributed equally to this work.


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Small Ag clusters incorporating both the pH-sensitive Raman probe molecule 4-mercaptobenzoic acid and a fluorescent dye are used to determine the local pH from the spatially mapped surface-enhanced Raman spectra correlated with the fluorescence, allowing simultaneous single-particle tracking and local pH sensing.