It has been reported that 50-60 Hz magnetic fields (MF) with flux densities ranging from microtesla to millitesla are able to induce heat shock factor or heat shock proteins in various cells. In this study, we investigated the effect of 60 Hz sinusoidal MF at 8 and 80 μT on the expression of the luciferase gene contained in a plasmid labeled as electromagnetic field-plasmid (pEMF). This gene construct contains the specific sequences previously described for the induction of hsp70 expression by MF, as well as the reporter for the luciferase gene. The pEMF vector was transfected into INER-37 and RMA E7 cell lines that were later exposed to either MF or thermal shock (TS). Cells that received the MF or TS treatments and their controls were processed according to the luciferase assay system for evaluate luciferase activity. An increased luciferase gene expression was observed in INER-37 cells exposed to MF and TS compared with controls (p < 0.05), but MF exposure had no effect on the RMA E7 cell line.

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One of the major problems of gene therapy is the efficient, specific, and targeted delivery as well as the safety of the materials used in such systems. The specific targeted delivery of genes to the lung offers the possibility to treat a variety of specific diseases. We developed chitosan nanoparticles with the plasmid pCEM-Luc, which contains a promoter activated by magnetic field. Nanoparticles of 200–250 nm obtained by ionic gelation with a 99% retention rate were transfected in B16F10 cells andin vivoin the lungs of Balb/c mice by intratracheal administration. We observed that an external magnetic field increased the expression of the luciferase reporter gene in B16F10 cells transfected with magnetic nanoparticles and in homogenized lungs of mice which determined differences in levels of expression between different regions of the lungs (apical or distal and left or right). The highest levels of luciferase activity were observed in the apical left region. The magnetic nanoparticles prove an efficient delivery system toin vitrotransfection of cells and lung tissue.

In cancer, the use of microbots based on anaerobic bacteria as specific transporters targeting tumor tissues has been explored since most solid tumors exhibit hypoxic regions. The aim of this study was to develop and characterize magnetic microbots based on Bifidobacteria and iron oxide fluorescent magnetic nanoparticles complexed with chitosan and a hypoxia inducible plasmid. In addition, the efficiency of the microbots for gene delivery to solid tumors was evaluated in an in vivo model by florescence and luminescence. To elaborate microbots, iron oxide fluorescent magnetic nanoparticles complexed with chitosan and a hypoxia-inducible plasmid called nanocomplex (NCs) with a size of 302 nm and a ζ potential of +16 mV were obtained and loaded onto Bifidobacteria membranes. Microbots with a diameter between 1–2 µm were characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Microbots were injected intravenously through the tail vein to tumor-bearing mice, and then a magnet was placed to focus them to the tumor area. Forty-eight hours after injection, the biodistribution was determined by florescence and luminescence. The greatest luminescence and fluorescence emitted were found in tumor tissue compared with the normal organs. We created a vector that can be directed by a magnet and deliver genes whose expression is regulated by hypoxic microenvironment of tumor.

Debido a la creciente utilización de la electricidad en la vida cotidiana, el ser humano está cada vez más expuesto a los campos electromagnéticos (CEM) que son generados por diversos aparatos, líneas de conducción y sub-estaciones eléctricas. Desde hace algunos años, ha surgido el interés sobre los efectos de estos campos en los sistemas biológicos. Se ha hecho énfasis en que los CEM son potencialmente capaces de afectar a nivel de síntesis de ADN, ARN y proteínas, además de la proliferación celular, y más recientemente se ha visto, que se puede alterar la expresión génica. Sin embargo, se han encontrado resultados variables, por lo que, hasta el momento, no se puede dar una conclusión definitiva sobre los efectos de este factor físico a los niveles antes mencionados. En este artículo, se presenta información general acerca del efecto biológico de los CEM, en particular en la expresión génica, incorporando además los últimos hallazgos al respecto que hemos obtenido en nuestro laboratorio. No se pretende una revisión exhaustiva del tema, sino más bien mostrar evidencias que indican que la expresión de diversos genes puede ser modificada por la radiación electromagnética, especialmente por la de frecuencia extremadamente baja (CEM), y que es ahora muy común en ciudades industrializadas.