Lineage-related and particle size-dependent cytotoxicity of chitosan nanoparticles on mouse bone marrow-derived hematopoietic stem and progenitor cells

Chitosan nanoparticles (CSNPs) have potential applications in stem cell research. In this study, ex vivo cytotoxicity of CSNPs on mouse bone marrow-derived (MBMCs) hematopoietic stem and progenitor cells (HSPCs) was determined. MBMCs were exposed to CSNPs of different particle sizes at various concentrations for up to 72 h. Cytotoxicity effect of CSNPs on MBMCs was determined using MTT, Live/Dead Viability/Cytotoxicity assays and flow cytometry analysis of surface antigens on HSCs (Sca-1⁺), myeloid-committed progenitors (CD11b⁺, Gr-1⁺), and lymphoid-committed progenitors (CD45⁺, CD3e⁺). At 24 h incubation, MBMCs' viability was not affected by CSNPs. At 48 and 72 h, significant reduction was detected at higher CSNPs concentrations. Small CSNPs (200 nm) significantly reduced MBMCs' viability while medium-sized particle (∼400 nm) selectively promoted MBMCs growth. Surface antigen assessment demonstrated lineage-dependent effect. Significant decrease in Sca-1⁺ cells percentage was observed for medium-sized particle at the lowest CSNPs concentration. Meanwhile, reduction of CD11b⁺ and Gr-1⁺ cells percentage was detected at high and intermediate concentrations of medium-sized and large CSNPs. Percentage of CD45⁺ and CD3e⁺ cells along with ROS levels were not significantly affected by CSNPs. In conclusion, medium-sized and large CSNPs were relatively non-toxic at lower concentrations. However, further investigations are necessary for therapeutic applications.     

Prenatal toxicity of synthetic amorphous silica nanomaterial in rats

Synthetic amorphous silica is a nanostructured material, which is produced and used in a wide variety of technological applications and consumer products. No regulatory prenatal toxicity studies with this substance were reported yet. Therefore, synthetic amorphous silica was tested for prenatal toxicity, according to OECD guideline 414 in Wistar rats following oral (gavage) administration at the dose levels 0, 100, 300, or 1000 mg/kg bw/d from gestation day 6–19. At gestation day 20, all pregnant animals were examined by cesarean section. Numbers of corpora lutea, implantations, resorptions, live and dead fetuses were counted. Fetal and placental weights were determined. Fetuses were examined for external, visceral and skeletal abnormalities. No maternal toxicity was observed at any dose level. Likewise, administration of the test compound did not alter cesarean section parameters and did not influence fetal or placental weights. No compound-related increase in the incidence of malformations or variations was observed in the fetuses. The no observed adverse effect level (NOAEL) was 1000 mg/kg bw/d.     

Improved food additive analysis by ever-increasing nanotechnology

Improper use of food additives may lead to potential threat to human health, making it important to develop sensitive and selective method for their detection. Nanomaterials with unique chemical and electrochemical properties show extensive applications in the design of food additive sensing systems. In this review, we summarize the recently adopted electrochemical and optical analysis of food additives based on nanomaterials. Detection of typical food additives (colorants and preservatives) by using different sensing mechanisms and strategies are provided. In addition, determination of illegal food additives is also briefly introduced. Finally, this review highlights the challenges and future trend of nanomaterial-based food analysis system.     

Nanostructural control of the release of macromolecules from silica sol–gels

The therapeutic use of biological molecules such as growth factors and monoclonal antibodies is challenging in view of their limited half-life in vivo. This has elicited the interest in delivery materials that can protect these molecules until released over extended periods of time. Although previous studies have shown controlled release of biologically functional BMP-2 and TGF-β from silica sol–gels, more versatile release conditions are desirable. This study focuses on the relationship between room temperature processed silica sol–gel synthesis conditions and the nanopore size and size distribution of the sol–gels. Furthermore, the effect on release of large molecules with a size up to 70 kDa is determined. Dextran, a hydrophilic polysaccharide, was selected as a large model molecule at molecular sizes of 10, 40 and 70 kDa, as it enabled us to determine a size effect uniquely without possible confounding chemical effects arising from the various molecules used. Previously, acid catalysis was performed at a pH value of 1.8 below the isoelectric point of silica. Herein the silica synthesis was pursued using acid catalysis at either pH 1.8 or 3.05 first, followed by catalysis at higher values by adding base. This results in a mesoporous structure with an abundance of pores around 3.5 nm. The data show that all molecular sizes can be released in a controlled manner. The data also reveal a unique in vivo approach to enable release of large biological molecules: the use more labile sol–gel structures by acid catalyzing above the pH value of the isoelectric point of silica; upon immersion in a physiological fluid the pores expand to reach an average size of 3.5 nm, thereby facilitating molecular out-diffusion.     

Application of graphene-based nanomaterials in stem cells北大核心

BACKGROUND: As a kind of newly-developing nanomaterial, graphene has been used in many fields. Many recent studies have found that graphene-based nanomaterials can affect the biological behaviors of stem cells. OBJECTIVE: To review the application and progress of graphene-based nanomaterials in stem cells. METHODS: We searched the articles about the application of graphene-based nanomaterials in stem cells published in PubMed, Web of Science, and CNKI databases with the search terms “graphene, nanomaterials, stem cell” in English and Chinese. Finally, 57 articles met the criteria for review. RESULTS AND CONCLUSION: Graphene-based nanomaterials have good stability and corrosion resistance, high mechanical strength, good biocompatibility, which are accepted as one of the most promising nanomaterials in biomedicine. Stem cells are undifferentiated cells that can differentiate into various mature cells in human body, which have a broad application prospect in tissue engineering, regenerative medicine and other fields. Many recent studies have applied graphene-based nanomaterials to stem cell research and found that they can affect the growth, proliferation, adhesion and differentiation of stem cells, and these nanomaterials may affect the biological behavior of stem cells by regulating the expression of related genes and various signaling pathways. However, graphene-based nanomaterials have biological toxicity, which restrict their application in biological aspects. Moreover, most researches only involved cellular level, and it needs further animal studies and in vivo experimental researches. © 2022, Publishing House of Chinese Journal of Tissue Engineering Research. All rights reserved.     

Evaluation of dermal and eye irritation and skin sensitization due to carbon nanotubes

The present paper summarizes the results of our studies on dermal and eye irritation and skin sensitization due to carbon nanotubes (CNTs), whose potential applications and uses are wide and varied, including CNT-enhanced plastics, electromagnetic interference/radio-frequency (EMI/RFI) shielding, antistatic material, flexible fibers and advanced polymers, medical and health applications, and scanning probe microscopy. Skin and eyes have the highest risk of exposure to nanomaterials, because deposition of nanomaterials to the surficial organs has the potential to be a major route of exposure during the manufacturing, use, and disposal of nanomaterials. Two products composed of single-walled carbon nanotubes (SWCNTs) and two products composed of multi-walled carbon nanotubes (MWCNTs) were tested regarding acute dermal and acute eye irritation using rabbits, and skin sensitization using guinea pigs. The concentrations of the CNTs in the substances were the maximum allowable for administration. The two products of SWCNTs and one of the products of MWCNTs were not irritants to the skin or eyes. The other product of MWCNTs caused very slight erythema at 24 h, but not at 72 h, after patch removal in the dermal irritation experiments and conjunctival redness and blood vessel hyperemia at 1 h, but not at 24 h, in eye irritation experiments. These findings showed that one product of MWCNTs was a very weak acute irritant to the skin and eyes. No products of SWCNTs and MWCNTs exhibited skin-sensitization effects. Our knowledge of the toxicological effects of CNTs is still limited. Further information is needed to clarify the potential for irritation and sensitization given the complex nature of CNTs.     

Rutile TiO₂ particles exert size and surface coating dependent retention and lesions on the murine brain

The rising commercial use and large-scale production of engineered nanoparticles (NPs) may lead to unintended exposure to humans. The central nervous system (CNS) is a potential susceptible target of the inhaled NPs, but so far the amount of studies on this aspect is limited. Here, we focus on the potential neurological lesion in the brain induced by the intranasally instilled titanium dioxide (TiO₂) particles in rutile phase and of various sizes and surface coatings. Female mice were intranasally instilled with four different types of TiO₂ particles (i.e. two types of hydrophobic particles in micro- and nano-sized without coating and two types of water-soluble hydrophilic nano-sized particles with silica surface coating) every other day for 30 days. Inductively coupled plasma mass spectrometry (ICP-MS) were used to determine the titanium contents in the sub-brain regions. Then, the pathological examination of brain tissues and measurements of the monoamine neurotransmitter levels in the sub-brain regions were performed. We found significant up-regulation of Ti contents in the cerebral cortex and striatum after intranasal instillation of hydrophilic TiO₂ NPs. Moreover, TiO₂ NPs exposure, in particular the hydrophilic NPs, caused obvious morphological changes of neurons in the cerebral cortex and significant disturbance of the monoamine neurotransmitter levels in the sub-brain regions studied. Thus, our results indicate that the surface modification of the NPs plays an important role on their effects on the brain. In addition, the difference in neurotoxicity of the two types of hydrophilic NPs may be induced by the shape differences of the materials. The present results suggest that physicochemical properties like size, shape and surface modification of the nanomaterials should be considered when evaluating their neurological effects.     

In vivo genotoxicity study of titanium dioxide nanoparticles using comet assay following intratracheal instillation in rats

Titanium dioxide (TiO₂) is widely used as a white pigment in paints, plastics, inks, paper, creams, cosmetics, drugs and foods. In the present study, the genotoxicity of anatase TiO₂ nanoparticles was evaluated in vivo using the comet assay after a single or repeated intratracheal instillation in rats. The nanoparticles were instilled intratracheally at a dosage of 1.0 or 5.0 mg/kg body weight (single instillation group) and 0.2 or 1.0 mg/kg body weight once a week for 5 weeks (repeated instillation group) into male Sprague–Dawley rats. A positive control, ethyl methanesulfonate (EMS) at 500 mg/kg, was administered orally 3 h prior to dissection. Histopathologically, macrophages and neutrophils were detected in the alveolus of the lung in the 1.0 and 5.0 mg/kg TiO₂ groups. In the comet assay, there was no increase in % tail DNA in any of the TiO₂ groups. In the EMS group, there was a significant increase in % tail DNA compared with the negative control group. TiO₂ nanoparticles in the anatase crystal phase are not genotoxic following intratracheal instillation in rats.     

What's new in Nanotoxicology? Brief review of the 2007 literature

The use and commercial potential of engineered nanomaterials is increasing, but questions of occupational and public health safety remain. Here, we review research published in 2007 concerning toxicology of nanomaterials. Articles were selected from the Medline Pubmed database, published or pre-published during 2007, using keywords (nanomaterials or nanoparticles or nanostructures) and (toxicity or health). From the 238 articles, we chose to concentrate mainly on research into carbonaceous (carbon nanotubes [CNTs] and fullerenes) and metallic materials (pure metal, oxides), because of their relevance. The induction of oxidative stress was repeatedly reported, and new information on the movement of nanomaterials through membranes was publicized. Concerning CNTs, information was revealed on DNA damage in vitro and pulmonary and systemic in vivo effects. Several of the reports failed to follow recent expert recommendations concerning good practice for nanotoxicologic research, complicating the integration of the new data into the larger picture of safety of nanomaterials.     

纳米材料和纳米技术在肿瘤放疗增敏中的研究进展

在肿瘤综合治疗中,放疗所占的比例日益增高,然而肿瘤细胞的放疗抵抗性和放疗带来的副作用依然是临床肿瘤治疗中不可忽视的问题.与传统放疗增敏相比,把新型的纳米材料和技术引入肿瘤放疗,将使肿瘤治疗呈现出治疗效率更高、细胞毒性更低的趋势.本文就纳米材料和纳米技术在肿瘤放疗增敏中的相关研究作一综述.