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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.

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.

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.

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.