Effect of Micelle Encapsulation on Toxicity of CdSe/ZnS and Mn-Doped ZnSe Quantum Dots

Abstract

The optical properties of quantum dots (QD) make them excellent candidates for bioimaging, biosensing, and therapeutic applications. However, conventional QDs are comprised of heavy metals (e.g., cadmium) that pose toxicity challenges in biological systems. Synthesising QDs without heavy metals or introducing thick surface coatings, e.g., by encapsulation in micelles, can reduce toxicity. Here, we examined the toxicity of micelle encapsulated tetrapod-shaped Mn-doped ZnSe QDs, comparing them to 3-mercaptopropionic acid (MPA)-capped Mn-doped ZnSe QDs prepared by ligand exchange and commercial CdSe/ZnS QD systems that were either capped with MPA or encapsulated in micelles. HepG2 cell treatment with MPA-coated CdSe/ZnS QDs resulted in a dose-dependent reduction of viability (MTT assay, treatment at 0–25 μg/mL). Surprisingly, no reactive oxygen species (ROS) or apoptotic signaling was observed, despite evidence of apoptotic behavior in flow cytometry. CdSe/ZnS QD micelles showed minimal toxicity at doses up to 25 μg/mL, suggesting that thicker protective polymer layers reduce cytotoxicity. Despite their shape, neither MPA- nor micelle-coated Mn-doped ZnSe QDs displayed a statistically significant toxicity response over the doses investigated, suggesting these materials as good candidates for bioimaging applications.

Study of the Scattering Effect by SiO2 Nanoparticles, in a Luminescent Solar Concentrator Sensitized with Carbon Dots

“…The latter are divided into the quantum dots derived from metals such as CdSe, PbS, and ZnSe and the organic quantum dots or carbon quantum dots. Metal-based quantum dots can be highly efficient luminescent materials; however, these materials have negative impacts on the environment and health [8,9]. Furthermore, with metallic quantum dots, after a certain time of use, the metallic ions become toxic materials for the environment and for health [10].…”

Novel “on–off” fluorescence sensing for rapid and accurate determination of Cr3+ based on g-CNQDs

“… 24 However, some common quantum dots, such as cadmium sulfide (CdS) and cadmium telluride (CdTe), have certain toxicities that will have harmful effects on human health and the environment. 25 Compared with traditional organic dyes and semiconductor quantum dots, graphitic carbon nitride quantum dots (g-CNQDs), as an emerging non-metallic semiconductor nanomaterial, not only maintain good water solubility, chemical stability, biocompatibility, and high photoluminescence quantum yield but also have the advantages of low cost, easy synthesis, non-toxicity, and green environmental protection. g-CNQDs have shown great promise for applications in photocatalysis, chemical and biological sensing, bioimaging, and drug delivery owing to their excellent optical properties.…”