Análisis de la evolución hidrogeoquímica y diagnóstico de procesos de biomineralización controlada en agua subterránea : caso Pozo UPTC, Sogamoso

1 recurso en línea (103 páginas) : ilustraciones color, figuras, tablas.Geomicrobiology has special interest in the role played by microorganisms in chemical cycles of chemical elements, including iron. Therefore, the incidence of bacteria in the absorption and reduction of elements of interest has been studied; Experimental studies have also been carried out on the use of catabolic processes of different bacteria as a bioremediation technique during the treatment of groundwater. However, the design of a formulation for the purification of this type of water, it is advisable to know the dynamics of the flow and the great part of the rock-water interaction processes that have influenced the chemical tool of the underground resource. In accordance with the above, it was pointed out the hydrogeochemical processes that have intervened in the evolution of the groundwater captured in the UPTC well, Sogamoso, and the iron and manganese removal capacity in the well water samples was evaluated from the exploitation of bacterial biomineralization processes. To do this, the sampling of eleven (11) samples of groundwater was carried out for the analysis of physicochemical parameters and the determination of the concentrations of the ionic content of interest. The processing of the information was done through hydrogeochemical diagrams (Piper, Stiff and Schoeller-Berkaloff) and some binary graphs that provide information on local conditions; and in a complementary manner, two (2) multivariate statistical methods were applied to quantitatively verify the results obtained through the hydrogeochemical analysis. In a complementary manner, the isotopic content of four (4) of the samples was analyzed to identify the possible recharge zones and, in this way, the preliminary hydrogeological model was constructed for the study area. The integration of this information allowed to define part of the natural and exogenous constituents to the dynamics of the underground flow. Additionally, an experimental method of bioremediation based on the biomineralization mechanisms, typical of the Magnetotactic Bacteria (MTB's) was tested, from which it was possible to eliminate part of the high content of Fe and Mn in the well waters. For this, it was required of the prospection of MTB at regional level, the isolation, the characterization and the verification of the magnetic response of the microorganisms, to finally, perform a process of inoculation of samples enriched with MTB in well water samples. This research for the opening to the future development of methodologies that include the use of microorganisms with magnetic properties and the use of bacterial biomineralization processes for the removal of medical crystals during the treatment of groundwater.La geomicrobiología tiene especial interés en el papel que desempeñan los microorganismos en los ciclos biológicos de los elementos químicos, entre ellos el hierro. Por ello, se ha estudiado la incidencia de bacterias en la absorción y reducción de elementos de interés; asimismo se han realizado estudios experimentales acerca de la utilización de los procesos catabólicos de diferentes bacterias como técnica de biorremediación durante el tratamiento de aguas subterráneas. No obstante, previo a cualquier formulación para la depuración de este tipo de aguas, es recomendable conocer la dinámica del flujo y gran parte de los procesos de interacción roca-agua que han incidido en la composición química del recurso subterráneo. Conforme a lo anterior, se analizaron los procesos hidrogeoquímicos que han intervenido en la evolución del agua subterránea captada en el pozo UPTC, Sogamoso, y se evaluó la capacidad de remoción de hierro y manganeso en muestras de agua del pozo a partir del aprovechamiento de los procesos de biomineralización bacteriana. Para ello, se realizó la toma de once (11) muestras de agua subterránea para el análisis de parámetros fisicoquímicos y la determinación de las concentraciones del contenido iónico de interés. El procesamiento de la información se realizó a través de diagramas hidrogeoquímicos (Piper, Stiff y Schoeller-Berkaloff) y algunos gráficos binarios que aportaran información de las condiciones locales; y de manera complementaria, se aplicaron dos (2) métodos estadísticos multivariantes para comprobar cuantitativamente los resultados obtenidos a través del análisis hidrogeoquímico. De manera complementaria, se analizó el contenido isotópico de cuatro (4) de las muestras, para identificar las posibles zonas de recarga y de esta manera construir el modelo hidrogeológico preliminar para el área de estudio. La integración de esta información permitió definir parte de los constituyentes naturales y exógenos a la dinámica del flujo subterráneo. Adicionalmente, se ensayó un método experimental de biorremediación basado en los mecanismos de biomineralización, propios de las bacterias Magnetotácticas (MTB’s), a partir del cual se logró remover parte del alto contenido de Fe y Mn en las aguas del pozo. Para ello, se requirió de la prospección de MTB’s a nivel regional, el aislamiento, la caracterización y la comprobación de la respuesta magnética de los microorganismos, para finalmente, realizar un proceso de inoculación de muestras enriquecidas con MTB´s en muestras de agua del pozo. Esta investigación da apertura al futuro desarrollo de metodologías que incluyan la utilización de microorganismos con propiedades magnéticas y el uso de procesos de biomineralización bacteriana para la remoción de elementos metálicos durante el tratamiento de aguas subterráneas.Bibliografía y webgrafía: páginas 94-103.PregradoIngeniero Geólog

The effect of iron-chelating agents on Magnetospirillum magneticum strain AMB-1: stimulated growth and magnetosome production and improved magnetosome heating properties

International audienceThe introduction of various iron-chelating agents to the Magnetospirillum magneticum strain AMB-1 bacterial growth medium stimulated the growth of M. magneticum strain AMB-1 magnetotactic bacteria and enhanced the production of magnetosomes. After 7 days of growth, the number of bacteria and the production of magnetosomes were increased in the presence of iron-chelating agents by factors of up to ∼2 and ∼6, respectively. The presence of iron-chelating agents also produced an increase in magnetosome size and chain length and yielded improved magnetosome heating properties. The specific absorption rate of suspensions of magnetosome chains isolated from M. magneticum strain AMB-1 magnetotactic bacteria, measured under the application of an alternating magnetic field of average field strength ∼20 mT and frequency 198 kHz, increased from ∼222 W/gFe in the absence of iron-chelating agent up to ∼444 W/gFe in the presence of 4 μM rhodamine B and to ∼723 W/gFe in the presence of 4 μM EDTA. These observations were made at an iron concentration of 20 μM and iron-chelating agent concentrations below 40 μM

Use of bacterial magnetosomes in the magnetic hyperthermia treatment of tumours: A review

International audienceWe review the most recent and significant results published in the field of magnetotactic bacteria (MTB), in particular data relating to the use of bacterial magnetosomes in magnetic hyperthermia for the treatment of tumours. We review different methods for cultivating MTB and preparing suspensions of bacterial magnetosomes. As well as the production of magnetosomes, we also review key data on the toxicity of the magnetosomes as well as their heating and anti-tumour efficiencies. The toxicity and efficiency of magnetosomes needs to be understood and the risk–benefit ratio with which to evaluate their use in the magnetic hyperthermia treatment of tumours needs to be measured

A Fluorescent Nanoprobe to Detect Local Temperature Changes During Antitumoral Hyperthermia Therapy

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Chains of Magnetosomes Extracted from AMB-1 Magnetotactic Bacteria for Application in Alternative Magnetic Field Cancer Therapy

International audienceChains of magnetosomes extracted from magnetotactic bacteria are shown to be highly efficient for alternative magnetic field cancer therapy. The viability of MDA-MB-231 breast cancer cells is relatively unaffected by the presence of less than ∼ 1 mg of chains of magnetosomes. When these cells are exposed to an oscillating magnetic field of frequency 183 kHz and field strengths of 20 to 60 mT, up to 100 % of them are destroyed. We show that it is possible to fully eradicate a tumor xeno-greffed on a mouse by administering a suspension containing ∼ 1 mg of chains of magnetosomes within the tumor and by exposing the mouse to three heat cycles of 20 minutes, during which the tumor temperature is raised to ∼ 43°C. We demonstrate the higher efficiency of the chains of magnetosomes compared with various other materials, i. e. whole inactive magnetotactic bacteria, individual magnetosomes not organized in chains and two different types of chemically synthesized nanoparticles currently tested for alternative magnetic field cancer therapy. The efficiency of the chains of magnetosomes is attributed to three factors, (i), a high magnetosome specific absorption rate (SAR), (ii), a homogenous distribution of the chains of magnetosomes within the tumor yielding uniform heating and (iii), the faculty of the chains of magnetosomes to penetrate within the cancer cells following the application of the alternative magnetic field, which enables intra-cellular heating. Biodistribution studies reveal that chains of magnetosomes administered directly within xeno-greffed breast tumors progressively leave the tumors during the 14 days following their administration and are then eliminated in the feces

Fluorescent magnetosomes for controlled and repetitive drug release under the application of an alternating magnetic field under conditions of limited temperature increase (<2.5 °C)

International audienceTherapeutic substances bound to nanoparticles have been shown to dissociate following excitation by various external sources of energies or chemical disturbance, resulting in controllable and efficient antitumor activity. Bioconjugation is used to produce magnetosomes associated with Rhodamine B (RhB), whose fluorescence is partially quenched by the presence of iron oxide and becomes strongly enhanced when RhB dissociates from the magnetosomes under the application of an alternating magnetic field. This novel approach enables the release of a RhB model molecule while monitoring the mechanism by fluorescence. The dissociation mechanism of RhB is highlighted by exposing a suspension of fluorescent magnetosomes to an alternating magnetic field, by magnetically isolating the supernatant of this suspension, and by showing fluorescence enhancement of the supernatant. Furthermore, to approach in vivo conditions, fluorescent magnetosomes are mixed with tissue or introduced in the mouse brain and exposed to the alternating magnetic field. Most interestingly, the percentages of RhB dissociation measured at the beginning of magnetic excitation (ΔR/δt) or 600 seconds afterwards (R600 s) are ΔR/δt ∼ 0.13% and R600 s ∼ 50% under conditions of limited temperature increases (<2.5 °C), larger values than those of ΔR/δt ∼ 0.02–0.11% and R600 s ∼ 13%, estimated for temperature increase larger than 2.5 °C. Furthermore, when magnetic excitations are repeated two to five times, the temperature increase becomes undetectable, but RhB dissociation continues to occur up to the fifth magnetic excitation. Since high heating temperatures may be damaging for tissues, this study paves the way towards the development of a safe theranostic dissociating nano-probe operating under conditions of limited temperature increase

Non-pyrogenic highly pure magnetosomes for efficient hyperthermia treatment of prostate cancer

We report the fabrication of highly pure magnetosomes that are synthesized by magnetotactic bacteria (MTB) using pharmaceutically compatible growth media, i.e., without compounds of animal origin (yeast extracts), carcinogenic, mutagenic, or toxic for reproduction (CMR) products, and other heavy metals than iron. To enable magnetosome medical applications, these growth media are reduced and amended compared with media commonly used to grow these bacteria. Furthermore, magnetosomes are made non-pyrogenic by being extracted from these micro-organisms and heated above 400 °C to remove and denature bacterial organic material and produce inorganic magnetosome minerals. To be stabilized, these minerals are further coated with citric acid to yield M-CA, leading to fully reconstructed chains of magnetosomes. The heating properties and anti-tumor activity of highly pure M-CA are then studied by bringing M-CA into contact with PC3-Luc tumor cells and by exposing such assembly to an alternating magnetic field (AMF) of 42 mT and 195 kHz during 30 min. While in the absence of AMF, M-CA are observed to be non-cytotoxic, they result in a 35% decrease in cell viability following AMF application. The treatment efficacy can be associated with a specific absorption rate (SAR) value of M-CA, which is relatively high in cellular environment, i.e., SARcell = 253 ± 11 W/gFe, while being lower than the M-CA SAR value measured in water, i.e., SARwater = 1025 ± 194 W/gFe, highlighting that a reduction in the Brownian contribution to the SAR value in cellular environment does not prevent efficient tumor cell destruction with these nanoparticles. KEY POINTS : • Highly pure magnetosomes were produced in pharmaceutically compatible growth media • Non-pyrogenic and stable magnetosomes were prepared for human injection • Magnetosomes efficiently destroyed prostate tumor cells in magnetic hyperthermia. Keywords: Alternating magnetic field; Cancer; Hyperthermia; Magnetosome; Magnetotactic bacteria; Nanotechnology

Biocompatible Coated Magnetosome Minerals for Application in the Magnetic Hyperthermia Treatment of Tumors

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Chains of magnetosomes with controlled endotoxin release and partial tumor occupation induce full destruction of intracranial U87-Luc glioma in mice under the application of an alternating magnetic field

International audiencePrevious studies showed that magnetic hyperthermia could efficiently destroy tumors both preclinically and clinically, especially glioma. However, antitumor efficacy remained suboptimal and therefore required further improvements. Here, we introduce a new type of nanoparticles synthesized by magnetotactic bacteria, called magnetosomes, with improved properties compared with commonly used chemically synthesized nanoparticles. Indeed, mice bearing intracranial U87-Luc glioma tumors injected with 13 μg of nanoparticles per mm3 of tumor followed by 12 to 15 of 30 min alternating magnetic field applications displayed either full tumor disappearance in 40% of mice or no tumor regression using magnetosomes or chemically synthesized nanoparticles, respectively. Magnetosome superior antitumor activity could be explained both by a larger production of heat and by endotoxins release under alternating magnetic field application. Most interestingly, this behavior was observed when magnetosomes occupied only 10% of the whole tumor volume, which suggests that an indirect mechanism, such as an immune reaction, takes part in tumor regression. This is desired for the treatment of infiltrating tumors, such as glioma, for which whole tumor coverage by nanoparticles can hardly be achieved

Development of non-pyrogenic magnetosome minerals coated with poly- l -lysine leading to full disappearance of intracranial U87-Luc tumors in 100% of treated mice using magnetic hyperthermia

International audienceMagnetic hyperthermia was reported to increase the survival of patients with recurrent glioblastoma by 7 months. This promising result may potentially be further improved by using iron oxide nanoparticles, called magnetosomes, which are synthesized by magnetotactic bacteria, extracted from these bacteria, purified to remove most endotoxins and organic material, and then coated with poly-l-lysine to yield a stable and non-pyrogenic nanoparticle suspension. Due to their ferrimagnetic behavior, high crystallinity and chain arrangement, these magnetosomes coated with poly-l-lysine (M-PLL) are characterized by a higher heating power than their chemically synthesized counterparts currently used in clinical trials. M-PLL-enhanced antitumor efficacy was demonstrated by administering 500–700 μg in iron of M-PLL to intracranial U87-Luc tumors of 1.5 mm3 and by exposing mice to 27 magnetic sessions each lasting 30 min, during which an alternating magnetic field of 202 kHz and 27 mT was applied. Treatment conditions were adjusted to reach a typical hyperthermia temperature of 42 °C during the first magnetic session. In 100% of treated mice, bioluminescence due to living glioblastoma cells fully disappeared 68 days following tumor cell implantation (D68). These mice were all still alive at D350. Histological analysis of their brain tissues revealed an absence of tumor cells, suggesting that they were fully cured. In comparison, antitumor efficacy was less pronounced in mice treated by the administration of IONP followed by 23 magnetic sessions, leading to full tumor bioluminescence disappearance in only 20% of the treated mice