## 2 Materials and Methods
### Multimodal Imaging System
\begin{table}
\begin{tabular}{c c} \hline
**No.** & **Specification** \\ \hline
1 & 785 nm diode laser, adjustable laser power (50–500 mW) \(\mid\) teç5 AG, Steinbach, Germany \\ \hline
2 & Multimode optical fiber with 100 \(\upmu\)m core diameter and FC/PC ferrules \(\mid\) Prinz Energietechnik GmbH, Stromberg, Germany \\ \hline
3 & Plano-convex lens, f = 25 mm, LA1951-B \(\mid\) Thorlabs Inc., Newton, NJ, USA \\ \hline
4 & Laser line filter, FWHM = 3.0 nm, #68–947 \(\mid\) Edmund Optics, Barrington, NJ, USA \\ \hline
5 & Dichoric mirror, HC BS R785 \(\mid\) AHF analysentechnik AG, Tubingen, Germany \\ \hline
6 & Microscope objectives: 5\(\times\), NA: 0.12, N-PLAN; BD20\(\times\), NA: 0.50, HC PL FLUORTA;BD50\(\times\), NA: 0.85, PL APO \(\mid\) Leica Microsystems, Wetzlar, Germany \\ \hline
7 & Gold-coated slide: BioGold®, 63479-AS \(\mid\) Science Services GmbH, München, GermanyGlass slide: SuperFrost® slide \(\mid\) VWR, Radnor, PA, USA \\ \hline
8 & Motorized microscope stage, EK 14 mot, travel range “3 \(\times\) 2” \(\mid\) Marzhäuser Wetzlar GmbH \& Co. KG \\ \hline
9 & Longpass filter, 785 LP Edge Basic Longpass Filter \(\mid\) AHF analysentechnik AG, Tubingen, Germany \\ \hline
10 & Achromatic lens, f = 30 mm, AC254-030-B \(\mid\) Thorlabs Inc., Newton, NJ, USA \\ \hline
11 & Multimode optical fibers with 100 \(\upmu\)m (FC/PC ferrules) + 600 \(\upmu\)m (FC/PC-SMA ferrules) core diameter \(\mid\) Prinz Energietechnik GmbH, Stromberg, Germany;FC/PC to FC/PC Mating Sleeve (ADAFC2) \(\mid\) Thorlabs Inc., Newton, NJ, USA \\ \hline
12 & Right-angle kinematic mirror mount (KCB/M) + dielectric mirror (BB1-E03) \(\mid\) Thorlabs Inc., Newton, NJ, USA, \\ \hline
13 & Translating mount (CXY1) + fiber adapter (SM1 FC) \(\mid\) Thorlabs Inc., Newton, NJ, USA \\ \hline
14 & Trinocular, microscope tube \(\mid\) Leica Microsystems, Wetzlar, Germany \\ \hline
15 + 23 & Halogen lamp, HLX CY6.35, 12 V, 100 W \(\mid\) Osram Licht AG, München, Germany \\ \hline
16 & Reflector: brightfield, darkfield or Smith \(\mid\) Leica Microsystems, Wetzlar, Germany \\ \hline
17 & Tube lens, 1.25\(\times\) \(\mid\) Leica Microsystems, Wetzlar, Germany \\ \hline
18 & Interchangeable photo adapter tube \(\mid\) Leica Microsystems, Wetzlar, Germany \\ \hline
19 & Color camera, DFK 41 AF0, 8-bit \(\mid\) The Imaging Source Europe GmbH, Bremen, Germany \\ \hline
20 & Diaphragm module RF \(\mid\) Leica Microsystems, Wetzlar, Germany \\ \hline
21 & Polarizer \(\mid\) Leica Microsystems, Wetzlar, Germany \\ \hline
22 & Analyzer IC/P with whole-wave compensator \(\mid\) Leica Microsystems, Wetzlar, Germany \\ \hline \end{tabular}
\end{table} 
Table 1: Description of the numbering depicted in Figure 1.  
slit. This spectrometer section is included in the MultiSpec(r) Raman System. Spectra are recorded using a thermoelectric (TE) cooled charge-coupled device (CCD) detector in a spectral range from 300 cm\({}^{-1}\) to 3200 cm\({}^{-1}\) with a spectral resolution of 7 cm\({}^{-1}\). For maximum power of excitation light at the sample surface, a right-angle kinematic mirror mount with a dielectric mirror (12), not illustrated in Figure 1b, enables the adjustment of the laser beam and consequently an optimum illumination of the objective's lens in the excitation path. In the detection path, a translating mount for the fiber adapter plate (13), not illustrated in Figure 1b, allows the lateral orientation of the pinhole fiber to maximize the detected Raman signal. Due to the weak Raman effect, the lenses in the Raman path contain an anti-reflective coating to reduce surface reflections. In addition, any optical component within the microscope stand, such as the tube optics, reflector or filter cubes, and beam splitters, is removed while performing Raman spectroscopy. The eyepieces of the trinocular (14) are removed permanently because of safety reasons. To obviate an undesired laser beam exit, the beam output is additionally covered. Since the observation path is disabled, the beam splitter of the trinocular is also permanently removed.