Cellular uptake under low temperature condition and in the presence of metabolic inhibitor. THP-1 (A) and A 549 (B) cells were exposed to 0.01 mg/ml of 30 nm SiO2NP over 1- 24 h time pried at 37°C, 4°C and 0.1% sodium azide. High content screening analysis for the cytosolic uptake of these particles was performed using an automated IN Cell Analyzer 1000 microscope and IN Cell Investigator image analysis software. Relative fluorescence intensity (RFU) represents the average of intensity value of cytosolic accumulation of these labelled nanoparticles when measured in PBS at pH 7.4. Data shown is normalised to untreated control and presented as mean values of three independent experiments performed in triplicate samples. Statistical analysis was carried out by 2-way ANOVA with Bonferroni post-test analysis and statistically significant data is reported by "*" symbol, for p < 0.05; "**" p < 0.01; "***" for p < 0.001.