The Chinese Academy of Sciences has made a series of progress in the research of bio-inorganic nanocomposites

With the continuous development of nanotechnology and its wide application in the field of biomedicine, it is becoming increasingly urgent and important to systematically study various nanomaterials and make a comprehensive biological evaluation. The research team of the National Nanoscience Center has conducted in-depth studies on the properties, physiological effects, mechanisms and biomedical applications of various natural protein-inorganic nanocomposites from the cell to the animal level, and has made a series of progress.

In terms of the effect of surface modification of chiral biomolecules on the cytotoxicity of quantum dots, the research team selected two groups of cadmium telluride (CdTe) quantum dots with different particle sizes and modified glutathione with different chiralities on their surfaces ( GSH) to obtain chiral quantum dots L-GSH-CdTe and D-GSH-CdTe. GSH-CdTe of each group showed chiral cytotoxicity and activation of autophagy on cultured human hepatoma cells, and the cytotoxicity of GSH-CdTe was closely related to its ability to induce autophagy. At the same time, GSH-CdTe causes the lysosomal stability and pH of the cell to decrease. Further research shows that due to the different chirality of glutathione on the surface of the two quantum dots, the efficiency of surface exchange with the free thiol-containing molecules in the environment is different, which in turn leads to the difference in stability of the two, which may be The main reason for its different biological effects. This study reveals the mechanism of cell metabolism and toxicity regulation related to the chirality of nanomaterial surface stabilizers, provides new ideas for designing safer biomolecular surface modifiers for medical imaging, and also suggests that autophagy may be nanomaterial-related cells A universal mechanism of poisoning. Related research results have been published online in Angew. Chem. Int. Ed. (DOI: 10.1002 / anie.201008206).

In terms of protein-guided synthesis of precious metal nanoparticles and their properties, the research team selected apoFt as a nanoreactor, using the hollow spherical cavity as a template, first synthesized a particle size of less than 2 nm, uniform size Platinum nanoparticles (Pt-Ft) with good dispersion and stability. Pt-Ft can simulate the activities of catalase (CAT) and horseradish peroxidase (HRP) under different conditions. The nano-simulated enzyme not only shows good stability under extreme conditions, but also shows a very different dependence on pH and temperature: when Pt-Ft simulates CAT activity, the activity of the simulated enzyme gradually increases with the increase of pH or temperature High temperature and high pH also have a synergistic effect on enzyme activity; when Pt-Ft simulates HRP, its activity is similar to the dependence of natural HRP on temperature and pH. The optimal pH is 4 and the optimal temperature is also similar. These unique properties make platinum nanoparticles Pt-Ft guided by apoferritin have good application prospects in the fields of biomedicine and environmental science. The results of this study were published in the recent Biomaterials (2011, 32, 1611-1618).

Subsequently, the research team continued to use natural deferritin as a nanoreactor and applied the "points of control" strategy to controllably synthesize various pairs of nano-gold clusters at the active site of ferritin heavy chain (Au-Ft). Compared with a single gold cluster, the synthesized Au-Ft composite not only retains the inherent photoluminescence characteristics of precious metal gold, but also exhibits variable fluorescence emission spectra, significant fluorescence enhancement characteristics, and red shift of the maximum emission wavelength, Thus directly verifying the existence of the interaction effect between the gold cluster pairs. Au-Ft has high biocompatibility and low cytotoxicity, and exhibits the targeting function of ferritin receptor mediated in vivo and in mice. Studies have shown that Au-Ft can be used as a fluorescent probe for holistic imaging of far-infrared biomedicine and has specific tissue targeting in mouse kidneys. This study provides an ideal method for synthesizing precious metal imaging agents in nanostructures with low toxicity and biological activity. Related research results were published online in the form of an article (Article) in J. Am. Chem. Soc. (DOI: 10.1021 / ja200746p).

This series of work of the research group combines the characteristics of biomolecules and inorganic nanomaterials, and provides new opportunities for the synthesis of various new bio-nanostructures with biomedical applications. The research work was supported by the Chinese Academy of Sciences, the 973 project of the Ministry of Science and Technology and the National Natural Science Foundation of China.

The Chinese Academy of Sciences has made a series of progress in the research of bio-inorganic nanocomposites

Chiral GSH surface modification affects the cytotoxicity of quantum dots: D-GSH-QDs are less cytotoxic than L-GSH-QDs, and the ability of quantum dots to induce cell death is related to their chiral-dependent autophagy-inducing ability

The Chinese Academy of Sciences has made a series of progress in the research of bio-inorganic nanocomposites

When Pt-Ft nanoparticles guided by apoferritin simulate catalase and horseradish peroxidase, the enzyme activity varies with pH and temperature

The Chinese Academy of Sciences has made a series of progress in the research of bio-inorganic nanocomposites

Deferritin-guided controlled synthesis of gold nanoclusters for localization of kidney and biomedical imaging in mice

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