| Autor: |
Gongalsky MB; Lomonosov Moscow State University, Faculty of Physics, Leninskie Gory 1, Moscow 119991, Russian Federation., Muftieva DA; Lomonosov Moscow State University, Faculty of Physics, Leninskie Gory 1, Moscow 119991, Russian Federation., Saarinen JKS; Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki FI-00014, Finland., Isomaki A; Biomedicum Imaging Unit, Faculty of Medicine, University of Helsinki, Haartmaninkatu 8 (PO Box 63), Helsinki 00014, Finland., Pervushin NV; Faculty of Fundamental Medicine, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russian Federation., Kopeina GS; Faculty of Fundamental Medicine, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russian Federation., Peltonen LJ; Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki FI-00014, Finland., Strachan CJ; Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki FI-00014, Finland., Zhivotovsky B; Faculty of Fundamental Medicine, Lomonosov Moscow State University, Leninskie Gory 1, Moscow 119991, Russian Federation.; Institute of Environmental Medicine, Division of Toxicology, Karolinska Institutet, Box 210, Stockholm SE-171 77, Sweden., Santos HA; Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki FI-00014, Finland.; Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki FI-00014, Finland., Osminkina LA; Lomonosov Moscow State University, Faculty of Physics, Leninskie Gory 1, Moscow 119991, Russian Federation.; Institute for Biological Instrumentation of Russian Academy of Sciences, Pushchino 142290, Moscow Region, Russian Federation. |
| Abstrakt: |
Coherent anti-Stokes Raman scattering (CARS), a nonlinear optical method for rapid visualization of biological objects, represents a progressive tool in biology and medicine to explore cells and tissue structures in living systems and biopsies. In this study, we report efficient nonresonant CARS imaging of silicon nanoparticles (SiNPs) in human cells as a proof of concept. As both bulk and porous silicon exhibit a high third-order nonlinear susceptibility, χ (3) , which is responsible for the CARS intensity, it is possible to visualize the SiNPs without specific labels. Porous and solid SiNPs were obtained from layers of porous and nonporous silicon nanowires and mesoporous silicon. Electron microscopy and Raman spectroscopy showed that porous SiNPs consisted of ∼3 nm silicon nanocrystals (nc-Si) and pores, whereas solid nanoparticles comprised ∼30 nm nc-Si. All types of SiNPs were nontoxic at concentrations up to 500 μg/mL after 24 h of incubation with cells. We demonstrated that although nc-Si possesses a distinguished narrow Raman band of about 520 cm -1 , it is possible to detect a high CARS signal from SiNPs in the epi-direction even in a nonresonant regime. 3D CARS images showed that all types of studied SiNPs were visualized as bright spots inside the cytoplasm of cells after 3-6 h of incubation because of the contrast provided by the high third-order nonlinear susceptibility of SiNPs, which is 1 × 10 4 to 1 × 10 5 times higher than that of water and typical biological media. Overall, CARS microscopy can provide localization of SiNPs within biological structures at the cellular level and can be a powerful tool for in vitro monitoring of silicon-based drug delivery systems or use SiNPs as labels to monitor various bioprocesses inside living cells. |
