Short term inhalation toxicity of a liquid aerosol of glutaraldehyde-coated CdS/Cd(OH)2 core shell quantum dots in rats

Toxicity of quantum dots on target organs and immune system

Quantum dots (QDs), due to their superior luminous properties, have been proven to be a very promising biological probe, which can be used as a candidate material for clinical applications. The toxicity of QDs in the environment and biological systems has caused widespread concern in the nanosphere, but their immune toxicity and their impact on the immune system are still relatively unknown. At present, the research on the toxicity of QDs is mainly focused on in vitro models, but few have systematically evaluated their adverse effects on target organs. Animal studies have shown that QDs can be accumulated in various organs due to their main exposure routes, thereby posing a potential threat to major organs. This review briefly describes general characteristics and the wide medical applications of QDs and focuses on the adverse effects of QDs on major target organs, such as liver, lung, kidney, brain, and spleen, after acute and chronic exposure. QDs mainly cause changes in the corresponding indicators of target organs, such as oxidative damage, and in severe cases cause hyperemia, tissue necrosis, and even death. In addition to causing direct damage to target organs, QDs can also cause a large number of immune cells to accumulate and cause inflammatory reactions when causing damage to other major organs. Whether it is to avoid the risk of people contacting QDs in production and life, or to realize the clinical applications of QDs, is very essential to conduct systematic in vivo toxicity assessment of QDs.

Nanotechnology-based Drug Delivery, Metabolism and Toxicity

BACKGROUND

Nanoparticles (NPs) are being used extensively owing to their increased surface area, targeted delivery and enhanced retention. NPs have the potential to be used in many disease conditions. Despite widespread use, their toxicity and clinical safety still remain a major concern.

OBJECTIVE

The purpose of this study was to explore the metabolism and toxicological effects of nanotherapeutics.

METHODS

Comprehensive, time-bound literature search was done covering the period from 2010 till date. The primary focus was on the metabolism of NP including their adsorption, degradation, clearance, and bio-persistence. This review also focuses on updated investigations on NPs with respect to their toxic effects on various in vitro and in vivo experimental models.

RESULTS

Nanotechnology is a thriving field of biomedical research and an efficient drug delivery system. Further their applications are under investigation for diagnosis of disease and as medical devices.

CONCLUSION

The toxicity of NPs is a major concern in the application of NPs as therapeutics. Studies addressing metabolism, side-effects and safety of NPs are desirable to gain maximum benefits of nanotherapeutics.

Protective Effect of Colla corii asini against Lung Injuries Induced by Intratracheal Instillation of Artificial Fine Particles in Rats

Environmental issues pose huge threats to public health, particularly the damage caused by fine particulate matter (PM_2.5). However, the mechanisms of injury require further investigation and medical materials that can protect the lungs from PM_2.5 are needed. We have found that Colla corii asini, a traditional Chinese medicine that has long been used to treat various ailments, is a good candidate to serve this purpose. To understand the mechanisms of PM_2.5-induced lung toxicity and the protective effects of Colla corii asini, we established a rat model of lung injury via intratracheal instillation of artificial PM_2.5 (aPM_2.5). Our results demonstrated that Colla corii asini significantly protected against lung function decline and pathologic changes. Inflammation was ameliorated by suppression of Arg-1 to adjust the disturbed metabolic pathways induced by aPM_2.5, such as arginine and nitrogen metabolism and aminoacyl-tRNA biosynthesis, for 11 weeks. Our work found that metabolomics was a useful tool that contributed to further understanding of PM_2.5-induced respiratory system damage and provided useful information for further pharmacological research on Colla corii asini, which may be valuable for therapeutic intervention.

Polydatin protects the respiratory system from PM2.5 exposure

Atmospheric particle is one of the risk factors for respiratory disease; however, their injury mechanisms are poorly understood, and prevention methods are highly desirable. We constructed artificial PM_2.5 (aPM_2.5) particles according to the size and composition of actual PM_2.5 collected in Beijing. Using these artificial particles, we created an inhalation-injury animal model. These aPM_2.5 particles simulate the physical and chemical characteristics of the actual PM_2.5, and inhalation of the aPM_2.5 in rat results in a time-dependent change in lung suggesting a declined lung function, injury from oxidative stress and inflammation in lung. Thus, this aPM_2.5-caused injury animal model may mimic that of the pulmonary injury in human exposed to airborne particles. In addition, polydatin (PD), a resveratrol glucoside that is rich in grapes and red wine, was found to significantly decrease the oxidative potential (OP) of aPM_2.5in vitro. Treating the model rats with PD prevented the lung function decline caused by aPM_2.5, and reduced the level of oxidative damage in aPM_2.5-exposed rats. Moreover, PD inhibited aPM_2.5-induced inflammation response, as evidenced by downregulation of white blood cells in bronchoalveolar lavage fluid (BALF), inflammation-related lipids and proinflammation cytokines in lung. These results provide a practical means for self-protection against particulate air pollution.

Susceptibility to quantum dot induced lung inflammation differs widely among the Collaborative Cross founder mouse strains

Quantum dots (QDs) are engineered semiconductor nanoparticles with unique physicochemical properties that make them potentially useful in clinical, research and industrial settings. However, a growing body of evidence indicates that like other engineered nanomaterials, QDs have the potential to be respiratory hazards, especially in the context of the manufacture of QDs and products containing them, as well as exposures to consumers using these products. The overall goal of this study was to investigate the role of mouse strain in determining susceptibility to QD-induced pulmonary inflammation and toxicity. Male mice from 8 genetically diverse inbred strains (the Collaborative Cross founder strains) were exposed to CdSe-ZnS core-shell QDs stabilized with an amphiphilic polymer. QD treatment resulted in significant increases in the percentage of neutrophils and levels of cytokines present in bronchoalveolar lavage fluid (BALF) obtained from NOD/ShiLtJ and NZO/HlLtJ mice relative to their saline (Sal) treated controls. Cadmium measurements in lung tissue indicated strain-dependent differences in disposition of QDs in the lung. Total glutathione levels in lung tissue were significantly correlated with percent neutrophils in BALF as well as with lung tissue Cd levels. Our findings indicate that QD-induced acute lung inflammation is mouse strain dependent, that it is heritable, and that the choice of mouse strain is an important consideration in planning QD toxicity studies. These data also suggest that formal genetic analyses using additional strains or recombinant inbred strains from these mice could be useful for discovering potential QD-induced inflammation susceptibility loci.

Curcumin/cellulose micro crystals/chitosan films: water absorption behavior and in vitro cytotoxicity

A new technique, called vapor induced phase inversion (VIPI), has been employed to fabricate cellulose micro crystals (CMC)-loaded chitosan (Ch) films. The method involves immediate exposure of CMC-dispersed chitosan solution to NH3 gas. The films were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analysis. The swelling ratio (SR) of films showed negative dependence on the cellulose content in the films. The dynamic water uptake data were interpreted by various kinetic models. Finally, the release of curcumin from the films was investigated. The CMC-loaded chitosan film showed slower release as compared to the plain chitosan film, suggesting that cellulose micro crystals acted as diffusion barrier. The films were non-cytotoxic, non-thrombogenic and non-hemolytic.

Effects of representative quantum dots on microorganisms and phytoplankton: a comparative study

In this paper, we put forward more effective and convenient approaches to prepare three kinds of high-quality CQDs. Then we assessed their effects on Staphylococcus aureus and Microcystis aeruginosa.

Application of short-term inhalation studies to assess the inhalation toxicity of nanomaterials

Background

A standard short-term inhalation study (STIS) was applied for hazard assessment of 13 metal oxide nanomaterials and micron-scale zinc oxide.

Methods

Rats were exposed to test material aerosols (ranging from 0.5 to 50 mg/m³) for five consecutive days with 14- or 21-day post-exposure observation. Bronchoalveolar lavage fluid (BALF) and histopathological sections of the entire respiratory tract were examined. Pulmonary deposition and clearance and test material translocation into extra-pulmonary organs were assessed.

Results

Inhaled nanomaterials were found in the lung, in alveolar macrophages, and in the draining lymph nodes. Polyacrylate-coated silica was also found in the spleen, and both zinc oxides elicited olfactory epithelium necrosis. None of the other nanomaterials was recorded in extra-pulmonary organs. Eight nanomaterials did not elicit pulmonary effects, and their no observed adverse effect concentrations (NOAECs) were at least 10 mg/m³. Five materials (coated nano-TiO₂, both ZnO, both CeO₂) evoked concentration-dependent transient pulmonary inflammation. Most effects were at least partially reversible during the post-exposure period.

Based on the NOAECs that were derived from quantitative parameters, with BALF polymorphonuclear (PMN) neutrophil counts and total protein concentration being most sensitive, or from the severity of histopathological findings, the materials were ranked by increasing toxic potency into 3 grades: lower toxic potency: BaSO₄; SiO₂.acrylate (by local NOAEC); SiO₂.PEG; SiO₂.phosphate; SiO₂.amino; nano-ZrO₂; ZrO₂.TODA; ZrO₂.acrylate; medium toxic potency: SiO₂.naked; higher toxic potency: coated nano-TiO₂; nano-CeO₂; Al-doped nano-CeO₂; micron-scale ZnO; coated nano-ZnO (and SiO₂.acrylate by systemic no observed effect concentration (NOEC)).

Conclusion

The STIS revealed the type of effects of 13 nanomaterials, and micron-scale ZnO, information on their toxic potency, and the location and reversibility of effects. Assessment of lung burden and material translocation provided preliminary biokinetic information. Based upon the study results, the STIS protocol was re-assessed and preliminary suggestions regarding the grouping of nanomaterials for safety assessment were spelled out.