Comparison of cytotoxic and inflammatory responses of photoluminescent silicon nanoparticles with silicon micron‐sized particles in RAW 264.7 macrophages

Abstract

Photoluminescent silicon nanoparticles have a bright and stable fluorescence and are promising candidates for bio-imaging, cell staining and drug delivery. With increasing development of nanotechnology applications for biomedicine, an understanding of the potential toxicity of nanoparticles is needed to assess safety concerns for clinical applications. The objective of this study was to compare biological responses of silicon nanoparticles (SNs, 3 nm diameter) with silicon microparticles (SMs, approximately 100-3000 nm diameter) in cultured murine macrophages (RAW 264.7) using standard protocols for assessing cytotoxicity/cell viability and inflammatory responses developed for micron-sized particles. SNs and SMs were exposed to macrophages with and without addition of endotoxin lipopolysaccharide (LPS), a positive inducer of tumor necrosis factor-alpha (TNF-alpha), interleukin 6 (IL-6), and nitric oxide (NO). Cytotoxicity was assayed using the dye exclusion and MTT assays. Cell supernatants were assayed for production TNF-alpha, IL-6 and NO. SNs at concentrations < or = 20 microg ml(-1) exhibited no cytotoxicity or inflammatory responses; however, SNs and SMs >20 and 200 microg ml(-1), respectively, increased cytotoxicity compared with controls. SMs induced concentration-related increases in TNF-alpha and IL-6 production; in contrast, the production of these cytokines was shown to decrease with increasing concentrations of SNs. NO production was not induced by SNs or SMs alone. Fluorescence microscopy demonstrated that SNs were associated with the macrophages, either internalized or attached to cell membranes. In conclusion, evaluating differences in biological responses for nanoparticles compared with microparticles of the same material may help improve tests to assess biological responses of nanoparticles that may be used in biomedical applications.

Antimicrobial silver-filled silica nanorattles with low immunotoxicity in dendritic cells

“…59 Choi et al showed, for example, that silicon nanoparticles are more cytotoxic than larger silicon microspheres due to differences in the specific surface area, the number of particles at the equivalent gram concentration and the internalization pathway. 60 The cytotoxicity of silver is highly dependent on its concentration: within a defined therapeutic window it has antimicrobial properties but does not affect mammalian cells, making it an effective antibacterial agent. 14 We show here that neither SiO 2 nanocontainers nor Ag@SiO 2 nanorattles affect the viability of dendritic cells except at the highest concentrations.…”

In Vitro Cytotoxicity and Molecular Effects Related to Silicon Nanoparticles Exposures

“…According to study results, HaCaT cells lines exposed to SiO (2) NPs showed cytotoxicity in a concentrationdependent and time-dependent manner (Gong et al 2012). In a research conducted on murine macrophages (RAW 264.7), Choi et al (2009) found that silicon NPs increased the cytotoxicity. Again, the results also support the observations of Yang et al (2010), who have showed that exposure of HaCaT cells to 15-nm and 30-nm SiO 2 particles resulted in significantly decreased cell viability in a dose-dependent manner.…”

Molecular Responses of Mouse Macrophages to Copper and Copper Oxide Nanoparticles Inferred from Proteomic Analyses

“…Most of the toxicological studies in this field have been focused on a few nanoparticles used either as health products, such as iron oxide (15,17,22), or in a variety of consumer products, such as silver (13,14), silica (9,12), and titanium dioxide (11,16,20,21).…”