Investigation Of Biological Effects Of Magnetic Field And Magnetic Property Difference Of Biological Samples

Although the understandings of physical properties of organism components are much better than before,they are still in its infancy.As biomagnetism are generally weak and organisms are rather complex,the magnetic properties of most organism components are still unknown,and the mechanisms and targets of the interactions between magnetic field and organisms are still unclear due to lacking of explorations.Here we measured magnetic susceptibility of various biological samples at a physiological temperature(37?/310 K)and in their corresponding solutions using superconducting quantum interferometer device(SQUID)based magnetic measurement system with ultra-high sensitivity and real-time signal detection function.Combining magnetic properties measurements and cellular phenotypes analysis under high magnetic field,we provide biological and physical mechanism bases for in-depth study of biological effects of magnetic field.1 The magnetic susceptibilities of biological samples are diverse.At physiological temperature,we tested magnetic susceptibilities,the degree of magnetization in response to an applied magnetic field,of a variety of biological samples,and found that most of tested biological samples are diamagnetic,but plasmid DNA and the cytoplasm of interphase human nasopharyngeal carcinoma cell(CNE-2Z)exhibit paramagnetic property.In addition,we found that tissues(including normal or cancerous)or cells with different origins possess different magnetic susceptibility.What's more,the magnetic susceptibility of other biological samples,such as protein powders are quite different with their solutions,which may relate to their internal compositions and states.2 High magnetic field realign subcellular structures of CNE-2Z.After magnetic treatment,the line connecting nucleus and cytoplasmic center of interphase cells tend to align in the direction of the magnetic field,which is not only a new discovery of the biological effect of magnetic field,but an evidence proving anisotropy of cell due to non-uniform distribution of cellular fractions.Defining the distance between two poles of spindle as the length of spindle long axis,for mitotic anaphase-B cells,the longer the spindle long axis,the smaller the angle between spindle long axis and the direction of magnetic field.However,the perform of mitotic anaphase-A cells are different.The reduced microtubule density caused by depolymerization of kinetochore microtubule may be the reason of weakened tendency of spindle align with their microtubule components after magnetic treatment,although the distance between the two poles of spindle become larger.3 Gradient magnetic field changes the position,orientation and morphology of subcellular components.We proved that even the small magnetic susceptibility differences among nuclei and cytoplasm could cause their relative location changes in ultra-high gradient magnetic field exposed interphase CNE-2Z cells using magnetic measurement toward separated cellular fractions and image analysis in cell.Unlike interphase cell nucleus,metaphase chromosomes are more inclined to move toward area with higher magnetic field intensity,implying a less diamagnetic property than cytoplasm or completely paramagnetism,and verifying the value of magnetic susceptibility measured previously,In addition,we found that different combination of magnetic intensity and gradient changes spindles vary.Interestingly,both of chromosomes dispersion of prometaphase and metaphase cells were reduced in the presence of magnetic field,suggesting external magnetic field can re-arrange chromosomes in cells.Moreover,the aspect ratio of spindles is perturbed by magnetic field,and the pole angle of spindles whose long axis are normal to the field direction is wider than spindles whose long axis is parallel to the magnetic field,suggesting a potential application as an effective tool for studying and regulating mitotic processes.4 Moderate intensity low frequency rotating magnetic field has different inhibitory effects on different types of tumor.In addition,we further studied the biological effects of moderate intensity low frequency rotating magnetic field(LF-RMF)on tumor-bearing mice.Our research shows that the anti-cancer effects of moderate intensity LF-RMF are tumor-specific.LF-RMF can inhibit tumor growth in mice bearing MDA-MB231 and MCF7 human breast cancer cells,but not in mice bearing GIST-T1 human gastrointestinal stromal cancer cells.This suggests that the magnetic properties of these two kinds of tumor tissues may be different which lead to distinct responses toward magnetic treatments.Moreover,the decreased alanine aminotransferase(ALT)levels and alleviation of liver injury in mice bearing MCF7 and GIST-T1 tumors indicates the potential clinical advantages of LF-RMF in liver protection in cancer patients.Although the new experimental methods exploration and the usage limitation of SQUID and high magnetic field devices resulted in relatively limited experimental data and there are many subsequent experiments needed to be carried out urgently.However,through magnetic susceptibility measurements toward various biological samples,we found that although the numeric values of biological samples magnetic properties are generally weak,the differences among them are obvious.Coupled with usage of high magnetic field devices and analysis of cell phenotypes,we discovered that the microscopic magnetic differences between subcellular structures would directly lead to different forces exerted on them by high magnetic field,indicating that the magnetic property differences of different type of biological samples could cause different responses after magnetic treatments.This not only facilitates the new applications of magnetic fields in biomedicine research but also provides a theoretical magnetism basis for biomagnetism and magnetobiology studies.