Water-Dispersible Fluorescent Silicon Nanoparticles That Modulate Inflammatory Response in Macrophages

Silicon nanoparticles (SiNps) are being explored as biomaterials in the design of fluorescent medical probes and immunomodulatory strategies. However, most of the synthesis methods reported in the literature to obtain SiNps show a complicated synthesis process, resulting in nanoparticles dispersed in solvents that are hardly compatible with biological applications. This work reports a simple methodology to synthesize SiNps dispersed in water. Some physicochemical properties such as size, structure, composition, and fluorescence are evaluated. Furthermore, biological properties such as in vitro cytocompatibility and dose-dependent macrophage response are reported. SiNps were demonstrated to be rounded under 10 nm diameter with a Si–Si crystalline structure. Results showed that SiNps are promising as cell fluorescent trackers since they fluoresce under ultraviolet wavelength irradiation. In this report, several immunocytofluorescence and enzyme-linked immunosorbent assay (ELISA) tests strongly suggest that SiNps are not only cytocompatible but also exert an anti-inflammatory effect on macrophages by downregulating the production of pro-inflammatory cytokines and upregulating anti-inflammatory cytokines. All of these results suggest that SiNps synthesized using our methodology are a suitable alternative to be used as an immunomodulatory fluorescent biomaterial.