Silicon Quantum Dots and Their Impact on Different Human Cells

Abstract

Silicon quantum dots (SiQDs) are interesting low-dimensional nanostructures whose unique optical and electronic properties can be exploited for imaging, biosensing, or drug delivery. SiQDs with a diameter of around 4 nm co-doped with boron and phosphorus and evincing fluorescence and dispersibility in aqueous solutions were studied with respect to their impact on different human cells. The level of SiQD cytotoxicity in different types of human cells À osteoblasts, monocytes, macrophages, and mesenchymal stromal cells À was determined. Exposing the cells to increasing concentrations of quantum dots under different conditions and the subsequent evaluation of their cytotoxicity provided an overview of cell-specific reactions to identical doses. The results revealed the importance of cultivation conditions (e.g., the formation of a protein corona on nanoparticles originating from the media supplement) as well as the significant impact of cell type (the increased sensitivity of monocytes to quantum dots in comparison to other cell types).

Immunomodulatory Potential of Differently-Terminated Ultra-Small Silicon Carbide Nanoparticles

“…The concentration gradient of the NPs used herein was based on our previous research on different types of ultra-small silicon-based NPs [42,44]. In both of these studies, said concentration gradients proved to have an impact on metabolic activity of osteoblastic cell line (SAOS-2).…”

Silicon Quantum Dot Supraparticles for Fluorescence Bioimaging

“…20−23 Cytotoxicity of Si QDs to different human cells has been studied by fluorescence imaging. 20,21,24,25 Furthermore, Si QDs can be conjugated with antibodies for biosensing using antigen−antibody reactions. 23,26 A drawback to use isolated Si QDs as phosphors is the weak emission intensity due mainly to the small excitation (absorption) cross section and the small luminescence quantum yield.…”

“…Si QDs are biocompatible and biodegradable nanophosphors that have potential to take the place of cadmium and lead chalcogenide QDs phosphors, especially in biomedical fields. Si QDs below 10 nm in diameter exhibit size-dependent luminescence in the red to near-infrared (NIR) wavelength range due to the quantum size effects. − There have been numerous researches to use Si QDs phosphors for bioimaging and -sensing. − Cytotoxicity of Si QDs to different human cells has been studied by fluorescence imaging. ,,, Furthermore, Si QDs can be conjugated with antibodies for biosensing using antigen–antibody reactions. , …”

Growth of Core–Shell Silicon Quantum Dots in Borophosphosilicate Glass Matrix: Raman and Transmission Electron Microscopic Studies

“…The latter scenario is important especially for biomedical applications, where the high dispersibility in aqueous media is crucial. 7,[13][14][15] Hydrophilic Si QDs dispersible in polar solvents can be produced by surface oxidation. 16,17 However, a colloidal solution of oxidized Si QDs usually exhibits only a defectrelated blue emission, [18][19][20] which is not suitable for biomedical applications.…”

“…Another strategy to attain solution dispersibility is by introducing surface charges, which prevent agglomeration of Si QDs in polar solvents by electrostatic repulsion. The latter scenario is important especially for biomedical applications, where the high dispersibility in aqueous media is crucial. ,− …”