Self-assembly of Gold Nanoparticle Chains between Nanoelectrodes

A novel strategy has been developed for construction of nanoparticle chains between nanoelectrodes with bifunctional molecules by taking advantage of linear aggregation of colloidal particles in organis solvents. As confirmed by scanning electron microscopy （SEM）,an individual nanoparticle chain bridged the electrode pair. The present approach makes this technique to be cheap and may be applicable in microelectronic industry.

The Preparation and Biocompatibility Study on Fe_2O_3 Magnetic Nanoparticles Used in Tumor Hyperthermia

Objective：To evaluate the in vitro and in vivo toxicity of self-prepared nanosized Fe2O3, which has the potential implication in tumor hyperthermia. Methods： Fe2O3 nanoparticles were prepared by improving co-precipitation, which characterization was detected by TEM, XRD, CMIAS, EDS. MTT assay was used to evaluate the in vitro cytotoxicity test; hemolytic test was carried out to estimate whether it has blood toxicity; Fe2O3 suspended in sterile 0.9% NaCl was intraperitoneally injected into Kumning mouse to calculate the LD50 ; micronucleus （MN） were reckoned to identify whether it is genotoxic. Results：The nanoparticles are brown spherical particles with diameter ranging from 8 to 15 nm, which have good decentralization and stability. The experiments also showed that the toxicity of the material on mouse fibroblast （L-929） cell lines was 0 - 1 degree ; it has no hemolysis activity; LD50 arrived at 5.45 g/kg^-1 after intraperitoneal injection of 1 ml suspension; micronucleus test showed that it has no genotoxic effects either. Conclusion： The results showed that the Fe2O3 nanoparticles are prepared successfully, the self-prepared nanosized Fe2O3 is a kind of high biocompatibility materials and perhaps it is suitable for further application in tumor hyperthermia.

Ultrathin FeS nanosheets with high chemodynamic activity for sensitive colorimetric detection of H_(2)O_(2) and glutathione

Iron chalcogenides have attracted great interest as potential substitutes of nature enzymes in the colorimetric biological sensing due to their unique chemodynamic characteristics.Herein,we report the preparation of ultrathin Fe S nanosheets(NSs)by a simple one-pot hydrothermal method and the prepared Fe S NSs exhibit strong Fenton-reaction activity to catalyze hydrogen peroxide(H_(2)O_(2))for generation of hydroxyl radical(^(·)OH).Based on the chromogenic reaction of resultant^(·)OH with 3,3,5,5-tetramethylbenzidine(TMB),we develop colorimetric biosensors for highly sensitive detection of H_(2)O_(2)and glutathione(GSH).The fabricated biosensors show wide linear ranges for the detection of H_(2)O_(2)(5–150μmol/L)and GSH(5–50μmol/L).Their detection limits for H_(2)O_(2)and GSH reach as low as0.19μmol/L and 0.14μmol/L,respectively.The experimental results of sensing intracellular H_(2)O_(2)and GSH demonstrate that this colorimetric method can realize the accurate detection of H_(2)O_(2)and GSH in normal cells(L02 and 3T3)and cancer cells(MCF-7 and He La).Our results have demonstrated that the synthesized Fe S NSs is a promising material to construct colorimetric biosensors for the sensitive detection of H_(2)O_(2)and GSH,holding great promising for medical diagnosis in cancer therapy.

Rotating magnetic field-controlled fabrication of magnetic hydrogel with spatially disk-like microstructures

Composite biomaterials with controllable mi- crostructures play an increasingly important role in tissue engineering and regenerative medicine. Here, we report a magnetic hydrogel composite with disk-like microstructure fabricated by assembly of iron oxide nanopartides during the gelation process in the presence of rotating magnetic field. It should be mentioned that the iron oxide nanoparticles here were synthesized identically following techniques of Fer- umoxytol that is the only inorganic nanodrug approved by FDA for clinical applications. The microstructure of nano- particles inside the hydrogel was ordered three-dimensionally due to the twist of the aligned chains of magnetic nano- particles which leads to the lowest state of systematic energy. The size of microstructure can be tuned from several micro- meters to tens of micrometers by changing the assembly parameters. With the increase of microstructure size, the magnetothermal anisotropy was also augmented. This result confirmed that the assembly-induced anisotropy can occur even for the several micron aggregates of nanopartides. The rotating magnetic field-assisted technique is cost-effective, simple and flexible for the fabrication of composite hydrogel with ordered microstructure. We believe it will be favorable for the quick, green and intelligent fabrication of some com- posite materials.

Electrochemical Detection of Single A-G Mismatch Using Biosens-ing Surface Based on Gold Nanoparticles

The study of small drug molecules interacting with nucleic acids is an area of intense research that has particular relevance in our understanding of relative mechanism in chemotherapeutic applications and the association between genetics （including sequence variation） and drug response. In this contribution, we demonstrate how the sequence-specific binding of an anticancer drug Dacarbazine （DTIC） to single base （A-G） mismatch could be sensitively detected by combining electrochemical detection with biosensing surface based on gold nanoparticles.

Studies on Cytochrome c Modified by [PtdienNO_3]Cl

For the first time, [PtdienNO_3]Cl was used as a stable reagent to modify ferricytochrome c and the reaction products were separated and purified with the CM-52 cation exchange chromatography. Five components were obtained, corresponding to the native cytochrome c single-labeled, dual-labeled, and triple-labeled derivatives as shown by the analysis of the molar ratio of the two metal atoms (Pt and Fe). The reduction potentials of these proteins were measured by differential pulse voltammetry. His-33 and Trp-59 were identified by^1HNMR as the binding sites of the platinum complex in the modified cytochrome c derivatives. Trp-59 was a conserved amino acid connected with the heme through hydrogen bond, which had not been modified by other transition metal complexes. The platinummodified cytochrome c derivatives might be valuable in exploring the role of the aromatic amino acids, especially Trp-59, in electron transfer.