Raman spectroscopy for monitoring the dissolution of silicon nanocrystals in model liquids and living cells

Raman spectroscopy is an informative experimental technique for studying the properties of both solid-state and biological objects. In this work, the Raman scattering method was used to study the dissolution of silicon nanocrystals (nc-Si) during their incubation in phosphate buffered saline (PBS) at 37 ° C, and with BT474 human breast carcinoma cells. Aqueous suspensions of silicon nanoparticles (SiNPs) with a diameter <90 nm were obtained by grinding arrays of porous silicon nanowires. The microphotographs of scanning and transmission electron microscopy show that nanowires and SiNPs consist of small nc-Si and pores. It was shown that incubation of nanoparticles in PBS and in cells results in a low-frequency shift of the maximum and broadening of the Stokes component of the Raman spectrum of SiNPs, the appearance of a signal from the amorphous silicon phase, a decrease in the intensity, and then complete disappearance of the signal, which indicates a decrease in the size, and then a complete dissolution of nc-Si. The results presented in this work are promising for the development of biodegradable drug delivery systems based on SiNPs.