Fig. 4

The effect of continuous live cell imaging on NP colocalization with lysosomes. A Experimental workflow: Cells were first stained with LysoTracker Red probe for 1 h, and then exposed to 20 μg/mL of 59 nm SiO₂-BDP FL NP in phenol free cRPMI. Cells were imaged continuously from 4 to 8 h. All the images were analyzed using ImageJ with a script (Script S2). Each cell was analyzed individually. B Pearson’s correlation coefficient (PCC) demonstrating correlation between NP and LysoTracker Red probe (lysosomes) at different time points. C Manders’ correlation coefficient M1 corresponds to the fraction of 59 nm SiO₂-BDP FL NP within lysosomes (stained with LysoTracker Red) and M2 corresponds to the fraction of lysosomes filled with NP. The corresponding histograms of fluorescence intensities of each channel are shown in Additional file 1: Fig. S5A