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. Author manuscript; available in PMC: 2017 Apr 26.
Published in final edited form as: Semin Ophthalmol. 2016;31(1-2):1–9. doi: 10.3109/08820538.2015.1114865

Figure 2. PEG-PLGA nanoparticles present the lowest ratio of DNA fragmentation in ARPE-19 cells.

Figure 2

DNA fragmentation or nicking, a characteristic hallmark of apoptosis, was assessed by TUNEL assay of ARPE-19 cells treated with PLGA, PCL, and PEG-PLGA NPs. (A) Fluorescence microscope images of TUNEL assay. Cells were incubated with 100 μg/ml of PLGA, PCL, and PEG-PLGA NPs or medium only (control). Blue channel represents cell nuclei stained by DAPI, and the green channel represents the DNA-nicked TUNEL positive apoptotic cells. (B) Quantitation of TUNEL positive cells. A total of 144 images per group were counted manually, and results are expressed as the ratio of TUNEL positive cells per 10,000 normal cells. Compared with the control, the PLGA NPs showed the highest and statistically significant toxicity on ARPE-19 cells, approximately 8-fold. Similarly, PCL toxicity also presented a significant increase in toxicity, in this case, 2-fold higher than control. In contrast, PEG-PLGA NPs presented a similar ratio of apoptotic cells to the control, without statistical significance. *p < 0.01.