Assessment of Toxicity of Cdse/Cds/Zns/S,S-Dihydrolipoic Acid/Polyacrylic Acid Quantum Dots at Danio rerio Embryos and Larvae

Abstract

Quantum dots (QDs) are nanosized semiconductor crystals. They are currently applied in different science fields such as medicine, namely, cancer diagnostics and treatment. QD toxicity is caused by the toxicity of their components. In vivo application of QDs requires their toxicity assessment, so the purpose of this work has been the estimation of acute and chronic toxicity of the QDs at Danio rerio embryos and larvae, QDs being composed of CdSe/CdS/ZnS/S,S-dihydrolipoic acid/polyacrylic acid. We have found no QD acute toxicity during 48 hours of QDs action at the embryo up to the concentration of 185 µM Cd. QDs have been found to be toxic only at 5-7 days of action, it shows that QDs act accumulatively. Beside lethality, we have observed different larval development defects, that is, differently localized edemas, lag of development, tail curvature, and swimming bladder malformation. Our experimental data as well as literature data show that toxicity of the quantum dots at Danio rerio embryos and larvae is primarily caused by toxic action of Cd 2+ ion which arises from partial dissociation of CdSe and CdS molecules.

Zwitterionic surface coating of quantum dots reduces protein adsorption and cellular uptake

“…We speculate that the core/shell/shell structure of the CdSe/CdS/ZnS QDs reduces the leaching of Cd 2+ as compared to CdSe or CdSe/ZnS QDs. 62 We further note that determination of the absolute QD concen- tration at which the cell viability becomes clearly compromised largely depends on the accuracy with which QD concentrations can be determined, which is in general not straightforward. 63 This is particularly true for the QDs used in this study, which comprise a semiconductor core and two semiconductor shells (tables for extinction coefficients 64 are available for cores only; addition of shells shifts the wavelength of the exciton peak and increases the extinction coefficient).…”

Biocompatible CdSe/ZnS quantum dot micelles for long-term cell imaging without alteration to the native structure of the blood plasma protein human serum albumin

“…1 Semiconductor quantum dots (QDs) are a type of probe that have potential therapeutic and biomechanical applications. [2][3][4][5][6][7][8][9] QDs have higher signal intensity than uorescent proteins and dyes, are photostable, and exhibit tunable emission from visible to infrared wavelengths and extensive absorption coefficients over a broad spectral range. Cadmiumbased QDs have demonstrated toxicity in both in vitro and in vivo studies.…”

Synthesis and properties of colloidal indium phosphide quantum dots

“…For example, cad mium based QDs are of great interest for biology and medicine as luminescence probes and visualizing labels [2]; however, cadmium is a carcinogenic substance that is dangerous to living organisms [3]. Some researchers have proposed different methods for the modification of cadmium QDs with the aim to reduce their hazardous ness [4], including the formation of additional semi conductor shells from, e.g., ZnS [5][6][7] and CdS [8], multilayer semiconductor shells [9,10], silicon dioxide shells [11], combined silicon dioxide-amphiphilic polymer shells [12], or those obtained from organosili con composites [13]. Such coatings (especially their combinations) may substantially improve the spectral luminescent properties of QDs and decrease the escape of Cd 2+ ions from the cores of the nanoparticles.…”