Nanoparticles (NP) are organic or inorganic substances, the size of which ranges from 1 to 100 nm, and they possess specific properties which are different from those of the bulk materials in the macroscopic scale. In a recent decade, NP were widely applied in biomedicine as potential probes for imaging, drug-delivery systems and regenerative medicine. However, rapid development of nanotechnologies and their applications in clinical research have raised concerns about the adverse effects of NP on human health and environment. In the present review, special attention is paid to the fetal exposure to NP during the period of pregnancy. The ability to control the beneficial effects of NP and to avoid toxicity during treatment requires comprehensive knowledge about the distribution of NP in maternal body and possible penetration through the maternal-fetal barrier that might impair the embryogenesis. The initial in vivo and ex vivo studies imply that NP are able to cross the placental barrier, but the passage to the fetus depends on the size and the surface coating of NP as well as on the experimental model. The toxicity assays indicate that NP might induce adverse physiological effects and impede embryogenesis. The molecular transport mechanisms which are responsible for the transport of nanomaterials across the placental barrier are still poorly understood, and there is a high need for further studies in order to resolve the NP distribution patterns in the organism and to control the beneficial effects of NP applications during pregnancy without impeding the embryogenesis.

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Background and Objective. Nanotechnology works with substances at a nanometer scale, and it offers many solutions for biomedicine. Nanoparticles (NPs) have been shown as effective agents for imaging, drug delivery, pathogen detection, etc. However, to date, NP toxicity is poorly known. The aim of our study was to investigate the embryotoxicity and teratogenicity of quantum dots (QDs) at the different stages of rat embryogenesis. Materials and Methods. Wistar rats were injected with CdSe/ZnS or CdTe QDs on the 6th, 13th, and 18th days of embryogenesis. Cyclophosphamide was chosen as a positive control of embryotoxicity. On the 21st day, the number of resorptions, weight, length, and external malformations of the embryos were estimated. Fluorescence spectroscopy and microscopy analysis were used to determine the accumulation of QDs in the tissues. Results. Exposure to cyclophosphamide during the pregnancy decreased the embryonic weight and length when compared with the control group and produced numerous malformations. The effects depended on the stage of embryogenesis. Meanwhile, QDs did not cause any embryotoxic or teratogenic effects. However, CdTe QDs induced necrosis in the tissues of the peritoneal cavity. The necrotic tissues contained QDs with altered spectroscopic properties. Spectroscopic and microscopic tissue examination revealed that QDs accumulated in the placenta, but no penetration to the embryonic tissues was observed. Conclusions. QDs did not cause any direct embryotoxic or teratogenic effects, but they had adverse effects on the maternal organism. The observed QD effects and the long-term accumulation of QDs in the maternal organism may increase the risk of adverse effects on embryo development.

For the successful use of quantum dots (QDs) in biomedicine their chemical and optical stability is of great importance. In this study the changes of photoluminescence parameters of CdTe QDs coated with mercaptopropionic acid (MPA) dependently on time and environment are presented. The presence of salt ions in the QD water solution decreases photoluminescence band intensity and induces red shift. The pH value of the solution also influences spectroscopic properties of QDs. In the pH range from 2.5 to 9 a decrease of photoluminescence intensity is observed. The fastest one, leading to the complete luminescence bleaching, occurs in the most acidic medium. Changes of QD spectral properties in cell growth media were studied as well. The results imply that spectroscopic changes of CdTe-MPA QDs are caused by the interactions between the ions present in the solution and ligand coating of QDs. The model of possible processes is proposed.

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Due to the active development and application of nanotechnology, nanoparticles have emerged as a new class of environmental pollutants. The aim of the study was to investigate quantum dots (QDs) access routes and distribution in embryos and larvae of rainbow trout Oncorhynchus mykiss and to determine the toxicity of QDs to rainbow trout larvae depending on the duration of exposure. CdSe/ZnS-COOH QDs at sublethal concentration was used during the toxicity test (1, 4 and 14 days). The results showed that QDs could get from the solutions into the larvae after hatching. QDs induced a significant increase in mortality, gill ventilation frequency and behavioral responses and a decrease in relative body mass in larvae at the end of the test. Larvae exposed to QDs were found to possess developmental malformations (blood clots). It was found that biological responses of larvae significantly depended on the duration of exposure to QDs.

Nevus with histopathologically confirmed nevomelanocytic atypia (dysplastic nevus) could not be distinguished from nevus without atypia using analyzed in vivo RCM features of melanocytic atypia. More accurate diagnostics by means of in vivo RCM needs further investigation on reflectance of single and nested cutaneous melanocytes in benign and malignant skin lesions.

The distribution of nanoparticles (NP) in an organism is an important issue for developing NP–based drug delivery systems and for general nanotoxicology. The knowledge of NP localisation in the skin is crucial for the optimisation of NP behaviour in vivo. Therefore, we have used semiconductor quantum dots (QD) to investigate their biodistribution in the skin by means of confocal fluorescence microscopy after subcutaneous injection. The results obtained showed that the diffusion of QD in the dermis is limited by basement membrane and dense connective tissue fibres, which resulted in negligible QD penetration into the epidermis, hair follicles, sebaceous and sweat glands, nerves and blood vessels. Low permeation of QD through the tissues results in slow clearance and raises the risks of potential immune, inflammatory and cytotoxic responses. The study reveals the significance of the tissue architecture for the interstitial and intracellular migration patterns of non‐functionalised QD.