Title: In situ imaging of bacterial metabolism by surface-enhanced Raman Scattering Spectroscopy
We report plasmonic Au@Ag@mSiO2 nanorattles for optophysiological monitoring of extracellular metabolism in bacterial populations by surface-enhanced Raman scattering (SERS). A key element of the SERS substrate is the mesoporous silica shell encapsulating single plasmonic nanoparticles, which furnishes colloidal stability and molecular sieving capabilities to the engineered nanostructures, thereby realizing robust, sensitive, and reliable measurements in biological media. We show that the plasmonic sensor allows space and time-resolved in situ monitoring of extracellular pH in bacterial colonies of Escherichia coli, as well as the detection of pyocyanin secretion by Pseudomonas aeruginosa. The reported SERS-based approach may be used as an alternative analytical tool for deciphering the role of extracellular metabolism in microbial interactions and virulence, as well as in the development of antimicrobial therapies.
1CINBIO, Universidade de Vigo, Departamento de Química Física, Campus Universitario As Lagoas, Marcosende, 36310 Vigo, Spain
2Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, 36310 Vigo, Spain