VEGFR-2 Targeted Cellular Delivery of Doxorubicin by Gold Nanoparticles for Potential Antiangiogenic Therapy
Arijit Das, Eric Soehnlen, Stephan Woods, Ravi Hegde, Amanda Henry, Arne Gericke and Soumitra Basu*
Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242, USA
Email:
Supporting Information:
Figure 1. Transmission Electron Microscopy picture of the Antibody-GNP-Dox (Au-antiVEGFR-2-Dox) nanoconjugate:
2. Surface Enhanced Raman Spectroscopy (SERS):
SERS is a technique that exploits the coupling between the surface plasmons of noble metal nanoparticles and NIR (Near Infra Red) laser light impinging on the particle. For molecules within this local optical field, a significant signal enhancement is observed that makes single molecule Raman spectroscopy feasible and enables the Raman spectroscopic characterization of single cells. The SERS effect is strongly distance dependent and only molecules in the immediate vicinity of the nanoparticle will be sampled by this technique. In the context of this study, SERS is used to explore whether the drug coated nanoparticles entered the cells. Since the SERS effect rapidly drops off with increasing distance from the nanoparticle, it can be safely assumed that the gold nanoparticle entered the cell if Raman bands characteristic for the interior of the cell (e.g., Raman bands linked to nucleotides) are observed in conjunction with bands associated with the drug and the antibody. To test the intracellular presence of the gold nanoparticles BAEC were treated with the nanoconjugates and analyzed by SERS to independently establish the presence of the gold nanoparticles inside the cells.
4. Table 1. Assignments of the vibrational bands observed in the SERS spectra (Figure 1).
Wavenumber (cm-1) / Peak assignments793 / (C-S)
831 / Tyr (CCH) aliphatic, Tyr ring
867 / Ribose (CC) ring breathing (COC)
988 / Proteins amide III
1084 / (PO2-), (CC), (COC)
1114 / Proteins (CN)
1131 / Proline
1185 / (CN), Tyr, Phe
1214,1246 / C,T,A ring
1272 / Amide III, (CH2, CH3)
1330 / Proteins: T(CH2, CH3)
1384 / Nucleotides, Proteins, Lipids, (CH3)sym
1404 / Histidine
1543 / Proteins Amide II
Abbreviations: stretching, deformation,T twisting C cytosine, T Thymine, A adenine
Assignment taken from: Kneipp J, Kneipp H, McLaughlin M, Brown D, Kneipp K (2006a) In vivo molecular
probing of cellular compartments with gold nanoparticles and nanoaggregates. Nano Lett 6 (10):2225-2231