Figure 3

Toxicity studies using conventional assays: XTT, LDH, and ATP assays. (A) BEAS-2B cells were treated with either 1 nM or 5 nM of 14 nm AuNPs for 1 hour prior to toxicity testing using the In Vitro Toxicology Assay Kit (XTT assay). Absorbance measured at 450 nm and a reference wavelength of 600 nm. (B) BEAS-2B cells were treated with either 1 nM or 5 nM of 14 nm AuNPs for 1 hour prior to toxicity testing using the CytoTox-ONE™ assay (LDH assay). Lysis solution was used as a positive control for maximum LDH release and sample LDH is expressed as a percentage of this maximum release. Fluorescence measured at 560 nm excitation, 590 nm emission. (C) BEAS-2B cells were treated with either 1 nM or 5 nM of 14 nm AuNPs for 1 hour prior to toxicity testing using the CellTiter Glo assay (ATP assay). Luminescent signal was measured and viability is expressed as a percentage of the untreated control cells. (D) The absorbance of 1 nM and 5 nM AuNPs in culture medium and with unreduced XTT at 450 nm. (E) Absorbance values obtained when data from (D) was subtracted from (A). (F) Luciferin substrate from the CellTiter Glo assay was incubated with ATP and 14 nm AuNPs to produce the luminescent product oxyluciferin prior to measurement of the luminescent signal.