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.