Linear and Non-Linear Optical Imaging of Cancer Cells with Silicon Nanoparticles

Abstract

New approaches for visualisation of silicon nanoparticles (SiNPs) in cancer cells are realised by means of the linear and nonlinear optics in vitro. Aqueous colloidal solutions of SiNPs with sizes of about 10–40 nm obtained by ultrasound grinding of silicon nanowires were introduced into breast cancer cells (MCF-7 cell line). Further, the time-varying nanoparticles enclosed in cell structures were visualised by high-resolution structured illumination microscopy (HR-SIM) and micro-Raman spectroscopy. Additionally, the nonlinear optical methods of two-photon excited fluorescence (TPEF) and coherent anti-Stokes Raman scattering (CARS) with infrared laser excitation were applied to study the localisation of SiNPs in cells. Advantages of the nonlinear methods, such as rapid imaging, which prevents cells from overheating and larger penetration depth compared to the single-photon excited HR-SIM, are discussed. The obtained results reveal new perspectives of the multimodal visualisation and precise detection of the uptake of biodegradable non-toxic SiNPs by cancer cells and they are discussed in view of future applications for the optical diagnostics of cancer tumours.

Bi‐Modal Nonlinear Optical Contrast from Si Nanoparticles for Cancer Theranostics

“…First, as we showed above, they can provide stronger TPEL and drastically stronger SHG signals, which is important for the implementation of nonlinear imaging modalities. Notice that TPEL has already been reported as an efficient information channel to track the presence of relatively small porous silicon‐based nanocrystals in vitro and in vivo . As follows from our data, larger crystals can provide much higher efficiency in such a mode of imaging (in our experiments, it was higher by 70%).…”

Super-resolution microscopy as a powerful tool to study complex synthetic materials

“…SIM is ideally suitable to perform live-cell studies due to the good temporal resolution and the minimum illumination power required. The exact intracellular localization of different nanomaterials has been determined thanks to the high particle localization accuracy of SIM [110][111][112][113] . In addition to the exact localization of the nanomaterial, SIM enabled the motoring of its degradation over time, as fragments of 100-200 nm could be imaged.…”

Two‐Photon‐Excited Silica and Organosilica Nanoparticles for Spatiotemporal Cancer Treatment

“…The potential of 3D‐resolved two‐photon‐actuated nanomedicine has been exploited via various nanomaterials such as semiconductor and carbon nanodots, polymeric, organic, silicon, gold, graphene and graphene oxide, silica hybrid, and other inorganic nanomaterials. What are the advantages of silica‐based nanoparticles?…”