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The subchronic toxicity of MgO NPs was studied by silkworm model, from the levels of animal entirety, tissues, and genes.

Neodymium (Nd) is one of the most famous members of rare earth elements family. With the increasing global demand for Nd, it can inevitably enter the environment and affect the ecological environment through the food chain and other ways. Therefore, it is very important to study the biological effects of Nd. In this study, the biological effects of 3 kinds of Nd compounds, i.e. neodymium oxide (Nd2O3), neodymium chloride (NdCl3) and neodymium nitrate (Nd(NO3)3), were evaluated by using silkworm models through the method of intravascular injection. Each of the three Nd compounds was prepared into 6 groups at different concentrations (40, 50, 60, 70, 80, 90 μg/μL). The results show that within the certain concentration range, Nd compounds show great damage to the growth of silkworms since high death rate is observed: the death rate from Nd2O3 group is floating between 30% and 80%, the one from NdCl3 group is between 17% and 33% and that from Nd(NO3)3 group is between 23% and 37%. It also reveals that Nd compounds have some negative effects on the body length and weight of silkworms. However, the histophysiological study shows that the three Nd compounds cause no obvious negative effects on the cell morphologies in midgut, fat body and silk gland. The XRD and FTIR spectra show that the secondary and the crystalline structures of silks are not destroyed, the TGA and DTG data exhibit that the thermal stability of silks is not damaged, and the tensile test shows that the mechanical properties of silks are not affected significantly by the intake of Nd compounds. In general, the intake of Nd compounds has significant inhibitory effects on silkworm growth but little negative impact on silk structures or cell morphology, the study can provide useful toxicological data for the safe application of Nd compounds in various fields.

Background. The incidence of esophageal squamous cell carcinoma in China ranks first in the world. The early diagnosis technology is underdeveloped, and the prognosis is poor, which seriously threatens the quality of life of the Chinese people. Epidemiological findings are related to factors such as diet, living habits, and age. The specific mechanism is not clear yet. Metabolomics is a kind of omics that simultaneously and quantitatively analyzes the comprehensive profile of metabolites in living systems. It has unique advantages in the study of the diagnosis and pathogenesis of tumor-related diseases, especially in the search for biomarkers. Therefore, it is desirable to perform metabolic profiling analysis of cancer tissues through metabolomics to find potential biomarkers for the diagnosis and treatment of esophageal squamous cell carcinoma. Methods. HPLC-TOF-MS/MS technology and Illumina Hiseq Xten Sequencing was used for the analysis of 210 pairs of matched esophageal squamous cell carcinoma tissues and normal tissues in Zhenjiang City, Jiangsu Province, a high-incidence area of esophageal cancer in China. Bioinformatics analysis was also performed. Results. Through metabolomic and transcriptomic analysis, this study found that a total of 269 differential metabolites were obtained in esophageal squamous cell carcinoma and normal tissues, and 48 differential metabolic pathways were obtained through KEGG enrichment analysis. After further screening and identification, 12 metabolites with potential biomarkers to differentiate esophageal squamous cell carcinoma from normal tissues were obtained. Conclusions. From the metabolomic data, 4 unknown compounds were found to be abnormally expressed in esophageal squamous cell carcinoma for the first time, such as 9,10-epoxy-12,15-octadecadienoate; 3 metabolites were found in multiple abnormal expression in another tumor, but upregulation or downregulation was found for the first time in esophageal cancer, such as oleoyl glycine; at the same time, it was further confirmed that five metabolites were abnormally expressed in esophageal squamous cell carcinoma, which was similar to the results of other studies, such as PE.

Copper nanoclusters (NCs) are increasingly favored by many researchers in the field of biochemistry. In this study, we have provided a method for the preparation of copper NCs based on a protein “turn-on” method, i.e. by immobilizing low-emissive copper nanoparticles (NPs) and proteins [human serum albumin (HSA), catalase, and lysozyme] together in polyacrylamide gel, high-fluorescent copper NCs can be achieved easily. The fluorescent color of HSA-mediated copper NCs is blue purple, the one of catalase-mediated copper NCs is pink yellow, and that of lysozyme-mediated copper NCs is orange red. The results show that the pore size of polyacrylamide gel, the ratio of protein to copper NPs and the modifiers of copper NPs have crucial effects on the yield of copper NCs. This method can also be used for the detection of the corresponding proteins, i.e. HSA, catalase, and lysozyme, based on the fluorescence of their respective copper NCs. The detection limits for the three proteins are all 0.02 mg mL−1, with a linear dynamic range from 0.02 to 2.00 mg mL−1 (HSA), 0.02 to 1.00 mg mL−1 (catalase), and 0.02 to 1.00 mg mL−1 (lysozyme). This method is simple and of low cost, which can be used for the identification of three proteins easily via a “turn-on” mode, which may have potential in biochemical analytical field for the detection of proteins or even more complex substances.

In this paper, Bombyx mori silkworm was used as a model animal to evaluate the biological effects of BSA-stabilized gold nanoclusters (BSA-Au NCs) via characterizing the growth status and silk properties of silkworms; the uptake of BSA-Au NCs by silkworms was realized by intravascular injection (the most dose of Au is 9.38 μg/silkworm). The results show that BSA-Au NCs have no obvious negative effects on the growth status of silkworms. WAXS and infrared results demonstrate that the crystalline or secondary structures of BSA-Au NCs-silks are not changed, but there is a slight increase in the helix/random coil content and a little decrease in the size and content of β-sheet compared with control-silks, suggesting that BSA-Au NCs confine the conformational transformation of silk fibroin to β-sheet from helix/random coil. Thermogravimetric analysis and tensile test results show that the thermal stability and mechanical properties (elongation at break, breaking strength and toughness modulus) of the BSA-Au NCs-silks are not weakened and the toughness modulus of the BSA-Au NCs-silks is increased, which may be attributed to the increase in the helix/random coil content. ICP-MS results demonstrate the accumulation and biodistribution of Au element in midgut, fat body and silk gland after the injection of 120 h, indicating that Au mainly distributes in midgut. In summary, BSA-Au NCs show no significant negative effect on silkworm when the dose of Au is below 9.38 μg/silkworm (about 6.25 mg kg−1). This study provides an efficient method for evaluating the biological effects of NCs, which will have a potential use in the biochemical field.

Boron nitride nanosheets (BN NSs), a novel material with great potential in biomedical applications, have attracted great attention due to its extraordinary properties. A crucial issue is the toxicity of BN NSs, which depends greatly on various factors, including size. The size may affect viability of cells due to the interactions between BN NSs and cell membranes. In this study, two kinds of silkworms (qiufeng × baiyu, Nistari 7019) were used as models to investigate the toxicity of BN NSs with different sizes (BN NSs-1: thickness of 41.5 nm, average diameter of about 200 nm; BN NSs-2: thickness of 48.2 nm, average diameter of about 500 nm) from the levels of animal entirety (silkworm mortality, silkworm growth, cocoons) and tissues. The results show that exposure to different sized BN NSs causes no obvious adverse effects on the growth or tissues of silkworm. This study has performed size-dependent in vivo toxicity evaluation of BN NSs and provided safety information to enrich the database for better application of BN NSs. Further studies should be carried out to discover the biosafety of diverse sizes and shapes BN NSs.

Silkworm silks have been widely used in a variety of fields due to their sensuousness, luster and excellent mechanical properties. Researchers have paid special attention in improving the mechanical properties of silks. In this work, Bombyx mori larval silkworms are injected with graphene quantum dots (GQDs) through a vascular injection to enhance mechanical properties of the silkworm silks. The GQDs can be incorporated into the silkworm silk gland easily due to hemolymph circulation and influence the spinning process of silkworm. The breaking strength, elongation at break and toughness modulus of the silks increase by 2.74, 1.33 and 3.62 times, respectively, by injecting per individual with 0.6 μg GQDs. Wide-angle X-ray scattering indicates that the size of β-sheet nanocrystals in GQDs-silks is smaller than that in control-silks. Infrared spectra suggest that GQDs confine the conformation transition of silk fibroin to β-sheet from random coil/α-helix, and the change of the size and content of β-sheet may be the reason for the improvement of the mechanical properties. The toxicity and safety limit of GQDs incorporated into each silkworm is also evaluated, and the results show that the upmost dose of GQDs per silkworm is 30.0 μg. The successful obtainment of reinforced silks by in vivo uptake of GQDs provides a promising route to produce high-strength silks.

Boron nitride nanosheets (BN NSs), a novel material with a structure similar to graphene, have attracted much attention due to their extraordinary properties. A deep in vivo study of the toxicity of BN NSs is indispensable, which can help to understand their potential risk and provide useful information for their safe application. However, so far as we know, the systematic in vivo toxicity evaluation of BN NSs hasn't been reported. In this study, silkworm (Bombyx mori) was used as a model to investigate the toxicity of BN NSs, by continuously feeding silkworm larvae with BN NSs at various mass concentrations (1%, 2%, 3%, 4%). The toxicity was evaluated from the levels of animal entirety (mortality, silkworm growth, cocoons and silk properties), tissues (pathological examination) and genes (transcriptomic profiling). The results show that the exposure to BN NSs causes no obvious adverse effects on the growth, silk properties or tissues of silkworm, but the expressions of genes in midgut concerned with some specific functions and pathways are significantly changed, indicating that BN NSs may have potential danger to lead to dysfunction. This study has performed in vivo toxicity evaluation of BN NSs and provided useful safety information for the application of BN NSs.