Abstract
Although ZnSe/ZnS quantum dots (QDs) have emerged as apparently less hazardous substitute to cadmium-based QDs, their toxicity has not been fully understood. Huge levels of ROS production and associated difficulties comprise the underlying reason for nanomaterial toxicity in cells. This will cause both immunotoxicity and genotoxicity. In the current work, Zinc Selenium/Zinc Sulphide (ZnSe/ZnS) QDs was synthesized, characterized and analyzed for its role in oxidative stress induction in two cell lines (HepG2 and HEK) and Swiss Albino mice. ROS production and influence of catalase activity in ROS production measured by DCFHDA assay in both HepG2 and HEK cells after exposure to ZnSe/ZnS QDs. Assessment of nitrile radical formation carried out by griess reagent. Level of GSH is assessed as a marker for oxidative stress induced by QDs. Cell death induced after exposure to ZnSe/ZnS QDs investigated by Calcein AM-PI live dead assay. Apoptotic DNA ladder assay carried out for studying the potential of ZnSe/ZnS QDs to induce DNA fragmentation. In vivo bio-nano interaction was studied by exposing Swiss Albino mice to ZnSe/ZnS QDs via i.v. and i.p. injection. Antioxidant assays were carried out in brain and liver homogenates to study the oxidative stress. LPO, GSH, GPx, GR and SOD are considered as biomarkers for the stress analysis. Blood brain barrier (BBB) integrity also studied. Spleenocytes proliferation assay was carried out to study the immunotoxicity response. ZnSe/ZnS QDs do not induce visible oxidative stress upto a concentration of 50 μg/ml. Cell death occurs at higher concentration (100 μg/ml) caused by ROS production. Overall study apparently provide attentive information that ZnSe/ZnS QDs is not capable of eliciting any serious damages to liver and brain tissues which in turn substantiates its applicability in biomedical applications.
Highlights
Quantum Dots (QDs) have attracted enough attention among researchers because of their wide ranging biomedical application potentials
Intracellular reactive oxygen species (ROS) production is one among the very primary responses happening in account of nanoparticle toxicity and DCFHDA was used for its measurement
Oxidative stress exerted by the ZnSe/ZnS QDs in both HepG2 and HEK cells studied, and the results clearly demonstrate that
Summary
Quantum Dots (QDs) have attracted enough attention among researchers because of their wide ranging biomedical application potentials. This wide range application is due to the size-tunable, discrete fluorescence emission, tunable surfaceproperties, efficient luminescence along with their unique photostability behavior (Medintz et al, 2005; Michalet et al, 2005; Xing and Rao, 2008) They are used in the development of solar cells (Milliron et al, 2004; Pal et al, 2012) and light-emitting diodes (Mocatta et al, 2011) in the electrical field as well as in therapeutic delivery (Diagaradjane et al, 2008; Hu et al, 2010; Walker et al, 2012) and cellular imaging (Bagalkot et al, 2007; Hu et al, 2010.; Muthu et al, 2012). These ions will induce ROS formation (Zhao et al, 2010; Tang et al, 2013; Katsumiti et al, 2014) and following oxidative stress (Lovri et al, 2005; Lee et al, 2009; Li et al, 2009)
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