Research Advances on Apoptosis Caused by Quantum Dots

Abstract

Recently, quantum dots (QDs) have been widely applied in biological and biomedical fields such as cell labeling, living tissue imaging, and photodynamic therapy because of their superior optical properties. Meanwhile, the potential biological negative effects and/or toxic effects of QDs have become increasingly important, especially the cytotoxicity caused by QDs. One of the common cytotoxicity when living organisms are treated with QD is apoptosis, where many attempts have been made to explain the mechanisms of apoptosis caused by QDs' use. One of the mechanisms is the production of cadmium ion (Cd(2+)) and reactive oxygen species (ROS). Excess generation of ROS will result in oxidative stress that would mediate apoptosis. Furthermore, the activation of cell death receptors and mitochondria-dependent such as B cell lymphoma 2 (Bcl-2) family and the caspase family could onset apoptosis. Signal transduction such as some classical signal pathways of PI3K-AKT, NF-E2-related factor 2 (Nrf2)-antioxidant response element (ARE), mitogen-activated protein kinases (MAPKs), and nuclear factor kappa B (NF-κB) also plays an important role in the regulation of apoptosis. Several ways to reduce the apoptotic rate have been introduced, such as surface modification, controlling, the dose, size, and exposure time of QDs as well as using antioxidants or inhibitors. In this review, we attempted to review the most recent findings associated with apoptosis caused by QDs so as to provide some guidelines for a safer QD application in the future.

Nanomaterial translocation–the biokinetics, tissue accumulation, toxicity and fate of materials in secondary organs–a review

“…It may be that other speciations of Ag (especially sulphidation by biomolecules) are also important. The Cd core of the QDs is often toxic-this has to be taken into account in the interpretation of QD bio-distribution and NM-mediated effects (Sanwlani et al 2014, Silva et al 2014, Zhan and Tang 2014. Finally, Ce NMs are distributed much like insoluble NMs, but it has been demonstrated that they are oxidised and re-crystallised as oxidised NMs in the liver (Graham et al 2014).…”

Quantum Dot‐Based Nanotools for Bioimaging, Diagnostics, and Drug Delivery

“…However,t he same silicon QDs hadn osuch effects in monkeys. [119] ROS-mediatedo xidative stress leads to apoptosis, whichc an be ad efense mechanism against the cytotoxicity of QD. Improvemento fs urface properties by coating QDs with polymers, the introductiono ff unctionalities, andt argeting might improvet he biodistribution and circulation half-lives of QDs.…”

“…[118] QDs can transfer www.chembiochem.org energy to some intracellular molecules, and form reactive oxygen species (ROS). [119] ROS-mediatedo xidative stress leads to apoptosis, whichc an be ad efense mechanism against the cytotoxicity of QD. [120] As reported in several papers, FRET from QD can be used to sensitize silicon photosensitizert hereby generating highly reactive singlet oxygen ( 1 O 2 )t od amage cancer cells.…”

Impairments of spatial learning and memory following intrahippocampal injection in rats of 3-mercaptopropionic acid-modified CdTe quantum dots and molecular mechanisms

“…Recently, the two pathways have been found to be necessary components in neural processing. [27][28][29] As we know, the apoptosis caused by QDs through inhibition of the survival-related signal-transduction proteins of Akt and ERK1/2 has been reported; 30,31 however, investigations of their roles in QD-induced adverse effects on the CNS are rare.…”