Nanoparticle cytotoxicity, lysosomal membrane permeabilisation and autophagy induction in kidney cells in vitro
Data collected in completion of a Masters of Science degree in Human Physiology.The datasets were aimed to investigate polyethylene glycol carboxyl gold nanoparticles (PEG-COOH AuNPs) uptake, cytotoxicity and possible autophagy induction in human embryonic kidney (HEK-293) cells in vitro. PEG-COOH AuNPs were firstly characterised in terms of their physicochemical properties when suspended in cell culture media and milli-Q water using transmission electron microscopy (TEM), absorbance spectroscopy, zeta potential meter and a pH meter. HEK 293 cells were then exposed to PEG-COOH AuNPs (0.5 nM -10 nM) for 24 hours and cytotoxicity was assessed using the xCELLigence real-time cell analyser (RTCA). Cellular uptake of PEG-COOH AuNPs (0.13 nM) was assessed using CytoViva dark-field microscopy. The internalisation of PEG-COOH AuNPs into vesicles was visualised using TEM.
Analytical interference of the PEG?COOH AuNPs with the LysoTracker green staining dye and the Western blot protein quantification assay kit was assessed prior to employing these techniques. Lysosomal membrane permeabilsation (LMP) was investigated using LysoTracker green staining by flow cytometry and Western blotting of microtubule-associated protein 1 light chain 3 (LC3) was quantified to assess autophagy induction. PEG-COOH AuNPs caused cytotoxicity in HEK 293 cells with an IC50 of 1 nM. PEG-COOH AuNPs were internalised by the HEK 293 cells and an increased number of vacuoles were observed. PEG-COOH AuNPs did not induce LMP despite the accumulation of the PEG-COOH AuNPs in vacuoles. No conversion of LC3I-LC3II was observed. However, LysoTracker green staining with flow cytometry is not an optimal assay as the auto-fluorescent properties of PEG-COOH AuNPs caused analytical interference. No interference of the PEG-COOH AuNPs with the Western blot protein quantification assay kit was observed. Investigation into the potential systemic effects of these particles is warranted due to their toxicity.