3D imaging
and spatial discrimination of two flavors of SERS nanotags
simultaneously using ring-collection ratiometric SESORS. (A) Schematic
showing the spatial discrimination experiment setup; images were collected
of the BPE and PPY powders beneath 3 and 9 mm of tissue in the same
sample across a 20 × 20 mm grid in 5 mm step sizes with various
linear offset magnitudes. This was repeated three times with the sample
being rotated through 360° in 90° steps to mimic the rotation
of the linear offset vector, and the resulting vectors were termed
with respect to the orientation of the vector in the initial set of
dx “0°” (green) images as dx “90°” (blue), dx “180°”
(yellow), and dx “270°” (red).
Ratiometric images were averaged across the four linear offset vectors
to mimic a ring-collection offset (pink). (B) Ratiometric images were
collected of the BPE powder buried beneath 3 mm of the tissue across
a 20 × 20 mm grid in 5 mm step sizes with linear offset magnitudes
of (i) 0, (ii) 2, (iii) 6, and (iv) 8 mm. This was repeated three
times with the sample being rotated through 360° in 90°
steps to mimic the rotation of the linear offset vector, and the resulting
vectors were termed with respect to the orientation of the vector
in the initial set of dx “0°”
(green) images as dx “90°” (blue),
dx “180°” (yellow), and dx “270°” (red). The ratiometric images
were averaged across the four linear offset vectors to mimic a ring-collection
offset (pink) at each offset magnitude. (C) Ratiometric images were
collected of the PPY powder buried beneath 9 mm of the tissue across
a 20 × 20 mm grid in 5 mm step sizes with linear offset magnitudes
of (i) 0, (ii) 2, (iii) 6, and (iv) 8 mm. This was repeated three
times with the sample being rotated through 360° in 90°
steps to mimic the rotation of the linear offset vector, and the resulting
vectors were termed with respect to the orientation of the vector
in the initial set of dx “0°”
(green) images as dx “90°” (blue),
dx “180°” (yellow), and dx “270°” (red). The ratiometric images
were averaged across the four linear offset vectors to mimic a ring-collection
offset (pink) at each offset magnitude. The color bars across each
set of ratiometric images were scaled for clarity to indicate the
offset that maximized the intensity ratio, INP/ITis. Spectra were collected
for 1 s using a laser power of 400 mW.