Skip to main content
. Author manuscript; available in PMC: 2012 Jun 28.
Published in final edited form as: ACS Nano. 2011 Jun 7;5(6):4729–4736. doi: 10.1021/nn201105r

Figure 3.

Figure 3

Raman signatures obtained from chemical controls for Cr(VI) and Cr(III) shown in (a) display the distinctive differences in their chemical spectra. (b). SERS Spectra obtained from S. oneidensis MR-1 loaded with intracellularly reduced gold islands indicate the presence of Cr(VI) peaks within the cells (black and green spectra, acquired from two different cells). The peaks from the chemical control (red) at 841 cm-1 perfectly align with the Cr(VI) peaks detected from within the cell. (c) Bacterial SERS spectrum (red) indicates presence of Cr(III) peaks and are aligned with those of chemical control - Cr(III) (black spectrum). The two peaks of Cr(III) present around 533 cm-1 are perfectly aligned with the intracellularly reduced Cr(III). Raman Intensity Maps (aerobic reduction: d-f & anaerobic reduction g-i) averaged over Phonon-Plasmon peak (∼ 230 cm-1) depicting the presence of intracellular pockets of gold nanoislands (d & g), localization of toxic hexavalent chromium- Cr(VI) (e & h) and reduced non-toxic chromium- Cr(III) (f & i) within a single cell.