Neurite development in PC12 cells cultured on nanopillars and nanopores with sizes comparable with filopodia

We investigated the effect ofnanoscale topography on neurite development in pheochromocytoma (PC12 cells) by culturing the cells on substrates having nanoscale pillars and pores with sizes comparable with filipodia. We found that cells on nanopillars and nanopores developed fewer and shorter neurites than cells on smooth substrates, and that cells on nanopores developed more and longer neurites than cells on nanopillars. These results suggest that PC12 cells were spatially aware of the difference in the nanoscale structures of the underlying substrates and responded differently in their neurite extension. This finding points to the possibility of using nanoscale topographic features to control neurite development in neurons.     

The effects of low-frequency environmental-strength electromagnetic fields on brain electrical activity: a critical review of the literature

Reports dealing with the stimulus-response relationship between low-level, low-frequency electromagnetic fields (EMFs) and changes in brain electrical activity permit assessment of the hypothesis that EMFs are detected by the body via the process of sensory transduction. These reports, as well as those involving effects on brain activity observed after a fixed time of exposure, are critically reviewed here. A consistent stimulus-response relationship between EMFs and changes in brain activity has been demonstrated in animal and human subjects. The effects, which consisted of onset and offset evoked potentials, were observed under conditions permitting the inference that the fields were transduced like ordinary stimuli such as light and sound. However, unlike the changes in brain activity induced by these stimuli, the changes induced by EMFs were governed by nonlinear laws. The studies involving attempts to determine whether a period of EMF exposure caused a metabolic effect reflected in pre-exposure/post-exposure differences in brain activity were generally inconclusive.     

Mathematical modeling and experimental analysis of the efficacy of photodynamic therapy in conjunction with photo thermal therapy and PEG-coated Au-doped TiO2 nanostructures to target MCF-7 cancerous cells

Some nanoscale morphologies of titanium oxide nanostructures blend with gold nanoparticles and act as satellites and targeted weapon methodologies in biomedical applications. Simultaneously, titanium oxide can play an important role when combined with gold after blending with polyethylene glycol (PEG). Our experimental approach is novel with respect to the plasmonic role of metal nanoparticles as an efficient PDT drug. The current experimental strategy floats the comprehensive and facile way of experimental strategy on the critical influence that titanium with gold nanoparticles used as novel photosensitizing agents after significant biodistribution of proposed nanostructures toward targeted site. In addition, different morphologies of PEG-coated Au-doped titanium nanostructures were shown to provide various therapeutic effects due to a wide range of electromagnetic field development. This confirms a significantly amplified population of hot electron generation adjacent to the interface between Au and TiO₂ nanostructures, leading to maximum cancerous cell injury in the MCF-7 cell line. The experimental results were confirmed by applying a least squares fit math model which verified our results with 99% goodness of fit. These results can pave the way for comprehensive rational designs for satisfactory response of performance phototherapeutic model mechanisms along with new horizons of photothermal therapy (HET) and photodynamic therapy (HET) operating under visible and near-infrared (NIR) light.     

50-Hertz electromagnetic fields induce gammaH2AX foci formation in mouse preimplantation embryos in vitro

Effects of electromagnetic fields (EMFs) on DNA damage in mammals are still controversial. In the present study, the effects of EMFs on DNA damage in preimplantation mouse embryos in vitro were investigated by using gammaH2AX foci formation, a new sensitive indicator for detecting DNA double-strand breaks (DSBs). The data obtained demonstrated that EMFs decreased the cleavage rate of preimplantation mouse embryos. This decreasing effect of EMFs was related to the DNA-damaging effect indicated by the induction of gammaH2AX foci formation in preimplantation mouse embryos. The inducing effects of EMFs on gammaH2AX foci formation could be inhibited by the treatment of noise MFs or wortmannin, a phosphatidylinositol 3-kinase (PI3K) family inhibitor. Furthermore, the data obtained also showed that EMFs could activate the DNA damage-repair mechanism by recruiting repair factor Rad50 to the damaged DNA sites to repair the corresponding DNA damage. These findings suggest that EMFs could cause DNA damage in preimplantation embryos in vitro and that the adverse effects of EMFs on development might at least partly act through DNA damage. The DNA damage induced by EMFs could be at least partly repaired by the natural activation of DNA damage-repair mechanism or prevented by the simultaneous treatment of noise magnetic fields.     

Neural stimulation on human bone marrow‐derived mesenchymal stem cells by extremely low frequency electromagnetic fields

Adult stem cells are considered multipotent. Especially, human bone marrow‐derived mesenchymal stem cells (hBM‐MSCs) have the potential to differentiate into nerve type cells. Electromagnetic fields (EMFs) are widely distributed in the environment, and recently there have been many reports on the biological effects of EMFs. hBM‐MSCs are weak and sensitive pluripotent stem cells, therefore extremely low frequency‐electromagnetic fields (ELF‐EMFs) could be affect the changes of biological functions within the cells. In our experiments, ELF‐EMFs inhibited the growth of hBM‐MSCs in 12 days exposure. Their gene level was changed and expression of the neural stem cell marker like nestin was decreased but the neural cell markers like MAP2, NEUROD1, NF‐L, and Tau were induced. In immunofluorescence study, we confirmed the expression of each protein of neural cells. And also both oligodendrocyte and astrocyte related proteins like O4 and GFAP were expressed by ELF‐EMFs. We suggest that EMFs can induce neural differentiation in BM‐MSCs without any chemicals or differentiation factors. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012     

Pulsating Electromagnetic Field in the Therapy of Headache

We investigated the effects of exposure to environmental electromagnetic fields (EMFs) in 1170 subjects. Neutrophil phagocytosis was enhanced in the low-intensity exposure groups, but reduced significantly at relatively high intensities. Visual reaction time was prolonged and the scores of short-term memory tests were lower in some high-intensity exposure groups. EMFs may affect the central nervous and immune systems in man.     

Anthropogenic Radio-Frequency Electromagnetic Fields Elicit Neuropathic Pain in an Amputation Model

Anecdotal and clinical reports have suggested that radio-frequency electromagnetic fields (RF EMFs) may serve as a trigger for neuropathic pain. However, these reports have been widely disregarded, as the epidemiological effects of electromagnetic fields have not been systematically proven, and are highly controversial. Here, we demonstrate that anthropogenic RF EMFs elicit post-neurotomy pain in a tibial neuroma transposition model. Behavioral assays indicate a persistent and significant pain response to RF EMFs when compared to SHAM surgery groups. Laser thermometry revealed a transient skin temperature increase during stimulation. Furthermore, immunofluorescence revealed an increased expression of temperature sensitive cation channels (TRPV4) in the neuroma bulb, suggesting that RF EMF-induced pain may be due to cytokine-mediated channel dysregulation and hypersensitization, leading to thermal allodynia. Additional behavioral assays were performed using an infrared heating lamp in place of the RF stimulus. While thermally-induced pain responses were observed, the response frequency and progression did not recapitulate the RF EMF effects. In vitro calcium imaging experiments demonstrated that our RF EMF stimulus is sufficient to directly contribute to the depolarization of dissociated sensory neurons. Furthermore, the perfusion of inflammatory cytokine TNF-α resulted in a significantly higher percentage of active sensory neurons during RF EMF stimulation. These results substantiate patient reports of RF EMF-pain, in the case of peripheral nerve injury, while confirming the public and scientific consensus that anthropogenic RF EMFs engender no adverse sensory effects in the general population.     

Nonthermal electromagnetic fields and estimation of the probable development of the convulsive syndrome

Development of the convulsive syndrome occurs during exposure to electromagnetic fields (EMFs) during physiotherapy and under conditions of professional work. Some researchers believe that EMFs may have medical effects during the treatment of the epilepsy syndrome. Some publications have noted the development of epileptic convulsions in experiments using EMF exposures at various frequencies. Four conditions that may promote the development of convulsions upon EMF exposure are considered.     

Optical Absorption in Overcoats of Nanoparticle Arrays on a Metallic Substrate

Surface plasma oscillations in metallic particles as well as in thin metallic films have been studied extensively in the past decades. New features regarding surface plasma excitations are, however, constantly discovered, leading, for example, to surface-enhanced Raman scattering studies and enhanced optical transmission though metal films with nanohole arrays. In the present work, the role of a metallic substrate is examined in two cases, one involving an overcoat of dielectric nanoparticles and the other an overcoat of metallic nanoparticles. Theoretical results are obtained by modeling the nanoparticles as forming a two-dimensional, hexagonal lattice of spheres. The scattered electromagnetic field is then calculated using a variant of the Green function method. Comparison with experimental results is made for nanoparticles of tungsten oxide and tin oxide deposited on either gold or silver substrates, giving qualitative agreement on the extra absorption observed when the dielectric nanoparticles are added to the metallic surfaces. Such absorption would be attributed to the mirror image effects between the particles and the substrate. On the other hand, calculations of the optical properties of silver or gold nanoparticle arrays on a gold or a silver substrate demonstrate very interesting features in the spectral region from 400 to 1,000 nm. Interactions between the nanoparticle arrays surface plasmons and their images in the metallic substrate would be responsible for the red shift observed in the absorption resonance. Moreover, effects of particle size and ambient index of refraction are studied, showing a great potential for applications in biosensing with structures consisting of metallic nanoparticle arrays on metallic substrates.     

SENSORY TRANSDUCTION AS A PROPOSED MODEL FOR BIOLOGICAL DETECTION OF ELECTROMAGNETIC FIELDS

Laboratory studies of the biological effects of low-frequency electromagnetic fields (EMFs) have demonstrated that the fields can produce or alter a wide range of phenomena. Explaining the diversity of the reported effects is a central problem. Our basic hypothesis is that the effects are generally indirect, and arise as a consequence of sensory transduction of the fields. In this view, EMF detection and its biological consequences occur in different types of cells. Experimental verification of the hypothesis will ultimately require data showing that the interaction of EMFs with tissue results in biological changes that are the same as or similar to changes that occur during sensory transduction. The goal was to identify the specific phenomena that would be expected to occur if the hypothesis were true. We therefore analyzed the presently accepted models of sensory transduction in the somatic and special senses. Many kinds of processes were identified in connection with transduction of different kinds of stimuli, but we found that a change in the conductance of a membrane ion channel in a neuron or a neuroepithelial cell was the earliest process that occurred in all forms of sensory transduction. Evidence from an appropriate model excitable cell or tissue that EMFs affect membrane currents or membrane potential would therefore support the hypothesis that EMF transduction is a species of sensory transduction.     

Effects of Electromagnetic Fields on the Bioactivities of an Osteoblast-Like Cell Line (UMR-106)

In the present study, we first investigated the effects of various types of low-energy, low-frequency electromagnetic fields (EMFs) on DNA synthesis in UMR-106 osteoblast-like cells. The experimental groups were exposed to EMFs for 2 days (twice/day, 30 min/time), and DNA synthesis was measured. The results showed that the cells responded most sensitively to EMFs of some specific combinations of the parameters by an increase in DNA synthesis, implying that EMFs with a specific waveform rather than a complex one can be used in clinical electrotherapy. The parameters were as follows: pulsed electric field (PEF) with pulse width 0.2 ms, field strength 10 V/cm, frequency 125 Hz; sinusoidal electric field (SEF) with field strength 1 V/cm, frequency 10 Hz; and alternating magnetic field (AMF) with field density 0.5 mT, frequency 5 Hz. In addition to frequency, the field strength or field density within a suitable intensity scale played a dominant role in causing the DNA synthesis response. We then compared the effects of two kinds of fields, PEF and AMF, with the optimum parameters identified by the experiments, on alkaline phosphatase (ALP) activity, protein and collagen synthesis, and intracellular levels of cyclic adenosine monophosphate (cAMP). The results indicated that both fields could not only affect UMR-106 cells proliferation but could particularly affect a series of characteristic bioactivities of UMR-106 such as ALP activity and collagen synthesis. The intracellular cAMP levels were increased rapidly and greatly with exposure to both PEF and AMF, implying that the action of low-frequency EMFs proceeds via second messenger-dependent processes originating from signals at the cell membrane. The difference in action between PEF and AMF suggests that they may couple to the cell membrane in a partially different way.     

Switchable DNA-origami nanostructures that respond to their environment and their applications

Structural DNA nanotechnology, in which Watson-Crick base pairing drives the formation of self-assembling nanostructures, has rapidly expanded in complexity and functionality since its inception in 1981. DNA nanostructures can now be made in arbitrary three-dimensional shapes and used to scaffold many other functional molecules such as proteins, metallic nanoparticles, polymers, fluorescent dyes and small molecules. In parallel, the field of dynamic DNA nanotechnology has built DNA circuits, motors and switches. More recently, these two areas have begun to merge—to produce switchable DNA nanostructures, which change state in response to their environment. In this review, we summarise switchable DNA nanostructures into two major classes based on response type: molecular actuation triggered by local chemical changes such as pH or concentration and external actuation driven by light, electric or magnetic fields. While molecular actuation has been well explored, external actuation of DNA nanostructures is a relatively new area that allows for the remote control of nanoscale devices. We discuss recent applications for DNA nanostructures where switching is used to perform specific functions—such as opening a capsule to deliver a molecular payload to a target cell. We then discuss challenges and future directions towards achieving synthetic nanomachines with complexity on the level of the protein machinery in living cells.     

The Effects of Electromagnetic Fields on Human Health:Recent Advances and Future

The potential of clectromagnetic ficlds(EMFs)for discase treatment and health enhancement has been actively pursued over the recent decades.This review first provides a general introduction about natural EMFs and related biological effcts.Then the recent progress on the EMF treatment of some common diseases(such as cancer,diabetes,wound healing and neurological diseases,etc.)has been carefully reviewed and summarized.Yet,the blindness on the selection of therapeutic EMF parameters still hinders the broad application ofEMF therapy.Moreover,the unclear mechanism of EMF function and poor reproducibility of experimental rcsults also remain big challenges in the field of bioclectromagnetics.Bionics is a useful methodology that gains inspiration from nature to serve human life and industry.We have discussed the feasibility of applying bionic approach on the selection of the rapeutic EMFs,which is based on thefindings of natural EMFs.Finally,we advocate that the detailed information of EMFs and biological samples should be thoroughly reorded in future research and reported in publications.In addition,the publication of studies with negative results should also be allowed.     

Role of reaction kinetics and mass transport in glucose sensing with nanopillar array electrodes

The use of nanopillar array electrodes (NAEs) for biosensor applications was explored using a combined experimental and simulation approach to characterize the role of reaction kinetics and mass transport in glucose detection with NAEs. Thin gold electrodes with arrays of vertically standing gold nanopillars were fabricated and their amperometric current responses were measured under bare and functionalized conditions. Results show that the sensing performances of both the bare and functionalized NAEs were affected not only by the presence and variation of the nanoscale structures on the electrodes but also by the reaction kinetics and mass transport of the analyte species involved. These results will shed new light for enhancing the performance of nanostructure based biosensors.     

Near- and Far-Field Plasmonic Properties of Different Types of Eccentric Core-Shell Nanodimers

Finite element method (FEM) simulations have been carried out on free-standing and finite dielectric substrate-supported eccentric (i) silica core-gold nanoshell dimers and (ii) gold core-silica nanoshell dimers for understanding their near- and far-field plasmonic properties. In the case of eccentric silica core-gold nanoshell dimers, multiple peaks are observed in the near- and far-field spectra due to the plasmon hybridization. The number of peaks is found to be sensitive to the core offset parameters of the nanoshells forming nanodimer. The wavelength locations of the peaks due to the constructive coupling of the lower order modes found relatively more sensitive to the dielectric substrate. The number of peaks in the near- and far-field spectra found the same presence and absence of the dielectric substrate. The values of full width at half maximum (FWHM) of the peaks observed in the near-field spectra are found larger as compared to those observed in the far-field spectra. In contrast, in the case of eccentric gold core-silica nanoshell dimers, multiple peaks have not been observed. The FWHM of the observed peak is found sensitive to the core offset parameters of the nanoshells, and the number of peaks in the near field- and far-field spectra found not same in the presence and absence of the dielectric substrate. Moreover, the differences in near- and far-field spectra of plasmonically coupled (i) concentric nanoshells, (ii) eccentric nanoshells, and (iii) concentric and eccentric nanoshells also investigated numerically.

     

Teratogenic effects of sinusoidal extremely low frequency electromagnetic fields on morphology of 24 hr chick embryos

To examine the potential teratogenicity of electromagnetic fields (EMF; sinusoidal and rectangular) on development of chick embryos (white leghorn), 221 freshly fertilized chicken eggs (55-65 g) were exposed during first 24 hr of postlaying incubation (38 degrees +/- 0.5 degree C) to 24 different EMFs, with 50Hz repetition rate and 8.007-10.143 mT flux density. Following exposure, the exposed fertilized chicken eggs (n = 8-10) and sham-exposed fertilized chicken eggs (n = 15) were incubated simultaneously for 8 more days and unexposed control fertilized chicken eggs (n = 20) for 9 days in absence of EMFs. The embryos were removed from egg shells and studied blind. All 24 EMF exposed-groups (inside the coil with exposure) showed an increase in the percentage of developmental anomalies compared to sham-exposed (inside the coil with no exposure) and control groups (outside the coil). Further, egg's weight was evaluated on day 9. This variable did not show significant difference between control and exposed-groups. The investigation also covered the measurement of body weight, length of crown to rump, length of tip of the beak to occipital bone, heart and liver weight. Statistical comparison between sham-exposed and control values did not show significant differences, but comparison between 8.007, 8.453 and 8.713 mT exposed-groups and control groups showed significant differences; in other exposed-groups, the changes were not significant. These results revealed that 50 Hz electromagnetic fields can induce irreversible developmental alterations in 24 hr chick embryos and confirm that its strength could be a determinant factor for the embryonic response to extremely low frequency electromagnetic fields (window effects).     

Effects of mobile phone radiofrequency on the structure and function of the normal human hemoglobin

Widespread use of mobile phones has increased the human exposure to electromagnetic fields (EMFs). It is required to investigate the effect of EMFs on the biological systems. In this paper the effect of mobile phone RF (910 MHz and 940 MHz) on structure and function of HbA was investigated. Oxygen affinity was measured by sodium dithionite with UV–vis spectrophotometer. Structural changes were studied by circular dichroism and fluorescence spectroscopy. The results indicated that mobile phone EMFs altered oxygen affinity and tertiary structure of HbA. Furthermore, the decrease of oxygen affinity of HbA corresponded to the EMFs intensity and time of exposure.     

Effects of Universal Mobile Telecommunications System (UMTS) electromagnetic fields on the blood-brain barrier in vitro

The extensive use of mobile phone communication has raised public concerns about adverse health effects of radiofrequency (RF) electromagnetic fields (EMFs) in recent years. A central issue in this discussion is the question whether EMFs enhance the permeability of the blood-brain barrier (BBB). Here we report an investigation on the influence of a generic UMTS (Universal Mobile Telecommunications System) signal on barrier tightness, transport processes and the morphology of porcine brain microvascular endothelial cell cultures (PBEC) serving as an in vitro model of the BBB. An exposure device with integrated online monitoring system was developed for simultaneous exposure and measuring of transendothelial electrical resistance (TEER) to determine the tightness of the BBB. PBEC were exposed continuously for up to 84 h at an average electric-field strength of 3.4-34 V/m (maximum 1.8 W/kg) ensuring athermal conditions. We did not find any evidence of RF-field-induced disturbance of the function of the BBB. After and during exposure, the tightness of the BBB quantified by 14C-sucrose and serum albumin permeation as well as by TEER remained unchanged compared to sham-exposed cultures. Permeation of transporter substrates at the BBB as well as the localization and integrity of the tight-junction proteins occludin and ZO1 were not affected either.     

Analgesic effect of the electromagnetic resonant frequencies derived from the NMR spectrum of morphine

Exposure to various types of electromagnetic fields (EMFs) affects pain specificity (nociception) and pain inhibition (analgesia). Previous study of ours has shown that exposure to the resonant spectra derived from biologically active substances' NMR may induce to live targets the same effects as the substances themselves. The purpose of this study is to investigate the potential analgesic effect of the resonant EMFs derived from the NMR spectrum of morphine. Twenty five Wistar rats were divided into five groups: control group; intraperitoneal administration of morphine 10 mg/kg body wt; exposure of rats to resonant EMFs of morphine; exposure of rats to randomly selected non resonant EMFs; and intraperitoneal administration of naloxone and simultaneous exposure of rats to the resonant EMFs of morphine. Tail Flick and Hot Plate tests were performed for estimation of the latency time. Results showed that rats exposed to NMR spectrum of morphine induced a significant increase in latency time at time points (p < 0.05), while exposure to the non resonant random EMFs exerted no effects. Additionally, naloxone administration inhibited the analgesic effects of the NMR spectrum of morphine. Our results indicate that exposure of rats to the resonant EMFs derived from the NMR spectrum of morphine may exert on animals similar analgesic effects to morphine itself.