Supplementary Data. In-Vivo Tumor Targeting and Spectroscopic Detection with Surface- Enhanced Raman Nanoparticle Tags

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1 Supplementary Data In-Vivo Tumor Targeting and Spectroscopic Detection with Surface- Enhanced Raman Nanoparticle Tags X.-M. Qian, 1 Xiang-Hong Peng, 2 Dominic O. Ansari, 1 Qiqin Yin-Goen, 3 Georgia Z. Chen, 2 Dong M. Shin, 2 Lily Yang, 2,4 Andrew N. Young, 3 May D. Wang, 5 and Shuming Nie 1,2 * 1 Departments of Biomedical Engineering and Chemistry, Emory University and Georgia Institute of Technology, 101 Woodruff Circle Suite 2001, Atlanta, GA 30322, USA. 2 Winship Cancer Institute, Emory University School of Medicine, 1365 Clifton Road, Atlanta, GA 30322, USA. 3 Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA. 4 Department of Surgery, Emory University School of Medicine, Atlanta, GA 30322, USA. 5 Departments of Biomedical Engineering and Electrical and Computer Engineering, Georgia Institute of Technology, 313 Ferst Drive, UA Whitaker Building 4106, Atlanta, GA 30332, USA. * Author to whom correspondence should be addressed; snie@emory.edu; phone ; fax

2 1. Stability of Pegylated SERS Nanoparticles under Harsh Conditions. Four independent techniques verified the high degree of stability of Au-MGITC-PEG-SH in concentrated PBS solution. PEG-SH coated and uncoated Au-MGITC complexes were examined by UV-vis absorption spectroscopy, TEM, DLS, and visual observation. (Supplementary Fig. 1) PBS addition to uncoated Au-MGITC immediately aggregated and precipitated the colloid as evidenced by dramatic spectral changes in UV-vis absorption spectrum, large aggregates in TEM, and the appearance of a distinct population of particles of nm hydrodynamic diameter, and an obvious color change from pink to clear. In contrast, PEG-SH coated Au-MGITC treated with PBS showed a preservation of the characteristic plasmon resonance peak of 60 nm gold, a majority of single particles by TEM (with a small population of clusters due to solvent evaporation), a unimodal, narrow size distribution of particles in DLS, and the pink color. We have also assessed the effects of a wide range of conditions encountered in bioconjugation and cell labeling procedures on the spectral signatures of PEG-SH coated SERS tags. Au-MGITC-PEG-SH was pelleted by centrifugation, redispersed in new solvents, and examined by SERS spectroscopy. There was no significant spectral changes when Au-MGITC-PEG-SH was redispersed in 10-fold concentrated PBS (1.37 M NaCl), basic water (ph 12), acidic water (ph 2), ethanol, and methanol comparing with reference spectrum of Au-MGITC in water (Supplementary Fig. 2). We did notice a slight change in relative peak intensities of the Raman bands at 1615, 1365, and 1172 cm -1 at ph 2 possibly due to relative orientation changes of MGITC on the Au surface, but no shift in vibrational frequencies was observed within the instrument resolution of 5 cm -1. Redispersion of Au-MGITC-PEG-SH in dimethylsulfoxide (DMSO) masked the 2

3 Supplementary Figure 1. Stability comparison of uncoated (left panel) and PEG-SH coated (right panel) Au-MGITC complexes. UV-vis absorption spectra of uncoated (a) and coated (b) Au-MGITC in water (solid curves) and PBS (dashed curves). TEM images of uncoated (c) and coated (d) Au-MGITC in PBS. DLS size distributions of uncoated (e) and coated (f) Au-MGITC in PBS. MGITC is the abbreviation for malachite green isothiocyanate (ITC). 3

4 Supplementary Figure 2. SERS spectra of Au-MGITC-PEG-SH redispersed in (a) pure water, (b) 10x PBS, (c) ph 12 aqueous solution, (d) ph 2 aqueous solution, (e) ethanol, (f) methanol, (g) DMSO, then transferred back to water. The reporter dye is malachite green isothiocyanate (MGITC), with distinct spectral signatures as labeled. Excitation wavelength: 633 nm; laser power: 5 mw. spectral features of the reporter due to the strong Raman cross section of DMSO. Interestingly, the original MGITC spectral signature was recovered after the DMSO solvated tag was stored under ambient conditions for 60 days and then redispersed in water (Supplementary Fig. 2g). Although uncoated Au-MGITC coalesced upon 4

5 centrifugation, PEG-SH coated SERS tags did not form aggregates under any of the above conditions tested. 2. SERS Spectra and Correlated Plasmonic Imaging of Single Cancer Cells. Tu686 and H520 cells were grown to confluence in an 8-chamber glass slide. ScFv-conjugated SERS tags at a concentration of 15 pm were introduced to 200 ul cell culture medium, and were then gently mixed for 30 min. After the incubation period, cells were washed thoroughly with PBS six times to remove free gold nanoparticles before imaging. The reflective mode darkfield images were obtained with ExamineR microscope (DeltaNu, Laramie, Wyoming) using 20X objective. A dark field condenser was used to deliver a narrow beam of white light from a tungsten lamp to the sample. In this mode, cells stained with SERS nano-tags on the cell membrane displayed bright golden color due to the highly scattering Supplementary Figure 3. SERS spectra and correlated surface plasmon imaging of single cancer cells. Upper panels: Reflective mode dark-field images of live Tu686 cells (EGFR positive) and H520 5

6 cells (EGFR negative) tagged with ScFv-conjugated gold nanoparticles. The images were acquired with Olympus Q-Color 5 CCD camera at an exposure time of 250 milliseconds. Lower panels: SERS spectra obtained from single cells as indicated by arrows. The Raman reporter dye is diethylthiatricarbocyanine (DTTC). Additional information on biomarker selection and image/data processing is available from the biocomputing and bioinformatics core of the Emory-Georgia Tech Center of Cancer Nanotechnology Excellence, and correspondence should be addressed to Dr. May D. Wang, Department of Biomedical Engineering, Georgia Tech and Emory University, 313 Ferst Drive, UA Whitaker Building 4106, Atlanta, GA 30332, USA, maywang@bme.gatech.edu. property of gold nanoparticles. EGFR-negative H520 cells showed a mostly dark background. The Tu686 EGFR-positive cells exhibited a high level of EGFR receptor binding while the H520 EGFR-negative cells had only limited EGFR expression. Single-cell SERS spectra were obtained by switching the microscope to the Raman mode with 785 nm laser excitation. The laser spot size using 20X objective was 5 x 10 μm at the focal plane. Supplementary Figure 3 showed the SERS spectra recorded from the areas as indicated by the arrows for EGFRpositive and EGFR-negative cells, respectively. Each spectrum was acquired with an exposure time of 10 seconds. 3. Biodistribution Studies of Nontargeted (Control) SERS Nanoparticles. To differentiate active tumor targeting from passive accumulation of nanoparticles at the tumor site, we have studied the behavior of nontargeted or control nanoparticles (that is, SERS nanotags that are not conjugated to any targeting ligand, but are similarly coated with a PEG layer and a nonspecific antibody or peptide). The control particles can passively accumulate in tumors through the EPR effect (enhanced permeability and retention effect), but cannot actively bind to tumor cells or undergo receptor-mediated endocytosis. Supplementary Figure 4 shows the in-vivo organ distribution data for two types of control SERS nanotags. 6

7 Supplementary Figure 4. Comparison of in-vivo distribution and tumor uptake data for plain PEGcoated nanoparticles and PEG-nanotags that are conjugated with a size-matched nonspecific protein (27- KD recombinant GFP). The data were obtained at 5 hours post injection by inductively coupled plasma mass spectrometric (ICP-MS) analysis of elemental gold. Note that both types of control nanoparticles showed similar behavior in liver and spleen accumulation. These nontargeted nanoparticles showed minimal tumor uptake, in contrast to that of targeted nanortags. 4. Intracellular Localization Studies by Transmission Electron Microscopy (TEM). Tumor, liver, spleen and kidney were examined with TEM to determine where the gold nanoparticles are deposited after cellular and tissue uptake. Supplementary Figure 5 shows a representative TEM image of tumor tissue sections when EGFRtargeted gold nanoparticles were injected systemically for in-vivo tumor targeting. The 7

8 data clearly shows that the gold nanoparticles are internalized into tumor cells (most likely via receptor-mediated endocytosis) and are located in intracellular organelles such as endosomes and lysosomes. Supplementary Figure 5. Transmission electron micrographs showing tumor uptake of EGFR-targeted gold nanoparticles, their clustering and and localization in intracellular organelles such as endosomes. The inset is an expanded view of gold nanoparticles in an organelle. Nu: cell nucleus. 8

9 To examine liver uptake of the nanoparticles, Supplementary Figure 6 shows a Kupffer cell (macrophages lining the liver sinudoidal surface) with gold nanoparticles captured in early- and late-stage endosomes. Note that the nanoparticles nonspecifically taken up by Kupffer cells are often isolated structures, in contrast to the clustered structures inside tumor cells. A significant number of gold nanoparticles are also identified inside spleen macrophage cells. In all other organs, gold particles are only found at very low densities. Overall, high-magnification TEM studies reveal that pegylated gold nanoparticles are taken up into intracellular organelles under in-vivo conditions, but their shape and morphology remain intact. Supplementary Figure 6. Transmission electron micrographs showing nonspecific uptake of gold nanoparticles by liver Kuffper cells. The boxed area is expanded in the lower panel showing primarily single gold nanoparticles localized in early- and late-stage endosomes (indicated by red arrows). 9

10 5. Passive Accumulation versus Active Targeting of SERS Nanoparticle Tags to Tumors see diagram below. Supplementary Figure 7. Schematic diagram showing pegylated SERS nanoparticles involved in active and passive tumor targeting. Both the control and targeted nanoparticles can accumulate in tumors through the EPR effect (enhanced permeability and retention effect), but only the targeted nanoparticles can recognize EGFR-positive cancer cells and rapidly enter these cells by receptormediated endocytosis. 10