Toxicity of Silver Nanoparticles in Macrophages

Abstract

Silver nanoparticles (nanosilver) are broadly used today in textiles, food packaging, household devices and bioapplications, prompting a better understanding of their toxicity and biological interactions. In particular, the cytotoxicity of nanosilver with respect to mammalian cells remains unclear, because such investigations can be biased by the nanosilver coatings and the lack of particle size control. Here, nanosilver of well-defined size (5.7 to 20.4 nm) supported on inert nanostructured silica is produced using flame aerosol technology. The cytotoxicity of the prepared nanosilver with respect to murine macrophages is assessed in vitro because these cells are among the first to confront nanosilver upon its intake by mammals. The silica support facilitates the dispersion and stabilization of the prepared nanosilver in biological suspensions, and no other coating or functionalization is applied that could interfere with the biointeractions of nanosilver. Detailed characterization of the particles by X-ray diffraction and electron microscopy reveals that the size of the nanosilver is well controlled. Smaller nanosilver particles release or leach larger fractions of their mass as Ag⁺ ions upon dispersion in water. This strongly influences the cytotoxicity of the nanosilver when incubated with murine macrophages. The size of the nanosilver dictates its mode of cytotoxicity (Ag⁺ ion-specific and/or particle-specific). The toxicity of small nanosilver (<10 nm) is mostly mediated by the released Ag⁺ ions. The influence of such ions on the toxicity of nanosilver decreases with increasing nanosilver size (>10 nm). Direct silver nanoparticle-macrophage interactions dominate the nanosilver toxicity at sizes larger than 10 nm.

Targeted Delivery of Silver Nanoparticles and Alisertib: In Vitro and In Vivo Synergistic Effect Against Glioblastoma

“…It is still uncertain and currently under debate whether the toxicity of AgNPs is a particlespecific effect [42] or whether it is caused by the dissolution of Ag + ions [43,44]. In our system, the synergistic effect may be based on the coexistence of the drug with Ag + ions formed from slow AgNPs dissolution, once they are released from the protective polymeric shell.…”

Optimization and integration of nanosilver on polycaprolactone nanofibrous mesh for bacterial inhibition and wound healing in vitro and in vivo

“…10 Several reports have found that the potential toxic effect caused by NS occurred only at high concentrations, and incorporated NS into biomaterials probably reduce the toxicity of NS. [11][12][13] Consequently, it is available to incorporate an optimized concentration of NS into a material to prepare an antibacterial wound dressing without cytotoxicity.…”

Silver nanoparticle exposure induces rat motor dysfunction through decrease in expression of calcium channel protein in cerebellum

“…Previous study indicates AgNPs may induce size dependent toxicity (Pratsinis et al, 2013). When the particle size is larger than 10 nm, the toxicity of AgNPs is primarily attributed to the dispersed particles rather than the released species due to its limited Ag + release (Pratsinis et al, 2013). It is further confirmed by Cronholm et al (2013), who showed that AgNPs entered into the cells in the form of particles, through intracellular uptake, with low amount of silver ion release.…”

“…As for metal nanoparticles that can release metal ions, one important question is whether the toxicity is mediated by the particles or the released ions. Previous study indicates AgNPs may induce size dependent toxicity (Pratsinis et al, 2013). When the particle size is larger than 10 nm, the toxicity of AgNPs is primarily attributed to the dispersed particles rather than the released species due to its limited Ag + release (Pratsinis et al, 2013).…”