Synthesis of magnetic nanobiomaterials and its biological effects.

Iron oxides and its hydrate nanoparticles, for example, nanoFe3O4 and nanoFe3O4 with hydroxyl, were synthesized by hydrothermal method, their sizes and features are evaluated by infrared spectra and Scanning Electron Microscope (SEM) etc. The dimensions of these nanoparticles produced are about 50-120 nm. In the investigation of influence of nanoFe3O4 and nanoFe3O4 with hydroxyl on crystalline states of amino acid molecules, their crystalline forms are different to that of pure amino acid molecules. The positions and widths of peaks of these nanoparticles in the infrared spectra of absorption are changed largely relative to that of pure amino acid molecules. From the experiments of microscope observation and infrared spectra of re-crytalline amino acids we see that the nanoFe3O4 and nanoFe3O4 with hydroxyl can change the structure of amino acid molecules. To study the toxicity of synthesized nanoparticles, the MTT (3-(4,5-dimethyl-thiazol 2-yl)-2,5 diphenyltetrazolium bromide) assay was used. The OD value (Optical Density) was used to calculated RGR (Relative Generation Rate) of cells, which determined the grade of cytotoxicity. The RGR of nanoparticles of iron oxide and its hydrate are about 1 to 2, which indicate that they have a lower toxicity.

A model for separation and melting of deoxyribonucleic acid in replication and transcription processes.

In order to explain the denaturation and melting in replication and transcription of deoxyribonucleic acid (DNA) at physiological temperature, we propose a dynamical model on the basis of structure and motion of DNA under the actions of energy released in hydrolysis of adenosine triphosphate (ATP) and enzymes. The model admits three degrees of freedom per base pair: two displacement variables associated with the vibrations of hydrogen atom in the hydrogen bonds and base (nucleotide), respectively, and an angular variable describing the rotation of base. The important role of hydrogen atom in the hydrogen bonds is stressed in this model. The Hamiltonian of the intact double helix system is given first, subsequently the equations of motion and solutions of a melting system are developed. The solutions represent the excited states formed by the displacements of hydrogen atoms and bases and the rotations of bases, arising from the energy absorbed by DNA, respectively. The results obtained show that the displacements of hydrogen atoms increase with time and along the helix. Once the displacements of hydrogen atoms and rotations of bases reach to certain limits, the hydrogen bonds are disrupted, and the two double helical strands of DNA are separated, a melting state in the replication or transcription process occurs. The properties of thermal motion of hydrogen atoms in this state at physiological temperature is further studied by using a transfer integral method and the thermodynamic properties such as free energy and entropy of the thermally excited state are obtained in the process. Values of characteristic parameters and critical temperature of melting in transcription process are derived. Finally the validity of the theory was demonstrated through comparison between experimental and theoretical data of specific heat and force of phase transition. This investigation is helpful to understand mechanism and essence of the replication or transcription process and promote quantitative description of these processes.

The influence of electromagnetic field irradiated by high-voltage transmission lines on properties of cells.

The influence of low-frequency electromagnetic field irradiating by high-voltage transmission lines on signal transduction of cell in spleen cells of the rates have been studied by molecular-biology techniques. The spleen cells are extracted from skilled rates, which are exposed in the electromagnetic field of high-voltage transmission lines with 4000 V/m and 0.09-0.1 G about 400 days. The quantity or level of phosphorylation of signal transducer and activator of transcription (STAT3) in JAK-STAT signal transduction pathway of spleen cells, which are stimulated and unstimulated by IL-2, respectively, are detected by the immunoblotting and immunobiochemistry. The results show that the expression of phospho-STAT3 in spleen cell stimulated by IL-2 differ not from that in the unstimulated cell. The former is significantly large than the latter. This shows that signal transduction of cell is affected by this electromagnetic field. The spectra of infrared absorption for the general G-proteins participating this signal transduction of cell for the controlled and exposed groups, which are measured by Nicoletic FT-IR 670 spectrometer, are obviously different both the intensity and frequency of these peaks. This shows that molecular structure or conformation of the proteins changes under influence of the electromagnetic field of high-voltage transmission lines, which results just to above changes of the JAK-STAT signal transduction of cell.

The Biological Effect of the NanoTiO2and Its Toxicity.

The proliferation behavior of the person's liver cell under actions of the nanoTiO2has been looked into by 3-(4,5-dimethylthiazol 2-yl)-2,5 diphenyltetrazolium bromide (MTT) colorimetric method of Mosmann. In this case we first give some elementary properties of the nanoTiO2and do further the liver cell cultures, and add the nano TiO2into the cells. In accordance with biological rules we measure the proliferation state of the liver cell in normal condition. The result obtained show that the influence of the nanoTiO2on the proliferation of the person's liver cell is very small, when compared with that of the control group. We found further out the size of the toxicity of the nanoTiO2to the chick embryo fibroblast (CEF) cells by the MTT colorimetric method. Thus we determine the toxicity for the TiO2s of 100nm and of 1000nm by the toxicology which are all first score (or degree).

Biological effects of the carbon nanotubes.

The influences of the carbon nanotubes on proliferation state of chick embryo fibroblast cells and toxicity of the nanotubes to the cells have been investigated by 3-(4,5-dimethylthiazol 2-yl)-2,5 diphenylte-trazolium bromide (MTT) colorimetric method of Mosmann and the toxicology. We found that the toxicity of the carbon nanotubes to the chick embryo fibroblast cells is small, it is about first score (or degree).