Publication: Caracterización de fármacos (emodina, ketorolaco, indometacina y piroxicam) sobre nanopartículas metálicas mediante espectroscopía molecular (SERS y MEF)
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2017-07-14
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Universidad Complutense de Madrid
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Abstract
La nanotecnología permite la manipulación de la materia a nivel nanométrico, tamaño en el que los efectos cuánticos son importantes. En el caso de la espectroscopía, molecular, y más concreto, en la espectroscopía Raman y de fluorescencia, el uso de nanopartículas (NPs) metálicas, da lugar a una amplificación de la señal de emisión que proviene de la muestra, debido a los plasmones superficiales localizados sobre dichas NPs (LSP, Localized Surface Plasmon). Este efecto ha permitido el desarrollo de nuevas técnicas espectroscópicas de alta sensibilidad, cuyos acrónimos en inglés son SERS (Surface Enhanced Raman Scattering) y, SEF (Surface Enhanced Fluroescence) o MEF (Metal Enhanced Fluorescence). La intensificación de la señal Raman o de fluorescencia de una molécula permite una mayor sensibilidad en su detección, pudiéndose, además, utilizar dichas señales para obtener imágenes de su distribución espacial en muestras sintéticas o biológicas. Estas técnicas presentan múltiples aplicaciones en el área de las Ciencias de la Salud, entre las que se incluyen el desarrollo de sistemas de liberación de fármacos y el tratamiento de enfermedades como cáncer, SIDA o Alzhéimer, y son las que se han utilizado en este trabajo. Debido, principalmente, a su constante dieléctrica, los metales más usados para fabricar NPs son la plata y el oro. El empleo de nanoestructuras de plata y oro presenta dos grandes ventajas: i) las moléculas se adsorben fácilmente sobre ellas sin necesidad de funcionalización o con una funcionalización sencilla y ii) los LSPs de dichas NPs son resonantes con láseres que emiten a 532 nm y 785 nm respectivamente. Las NPs metálicas pueden modificarse para optimizar su función, por ejemplo, pueden recubrirse de una capa de óxido de silicio formando nanoestructuras tipo “core-shell”, que permiten intensificar dicha señal en función del grosor de la capa de recubrimiento que separa el metal de las moléculas de fluoróforo. También pueden inmovilizarse en los poros de ciertos materiales, como el silicio poroso (PSi), que es uno de los componentes mesoporosos utilizado actualmente en nanotecnología. El PSi es biocompatible y presenta fotoluminiscencia en el visible lo que permite registrar la presencia de moléculas no fluorescentes inmovilizadas en la superficie de sus nanoporos...
Nanotechnology allows matter manipulation at nanometric level, size at which quantic effects are important. Considering molecular spectroscopy, specifically Raman and fluorescence spectroscopy, the use of metal nanoparticles (NPs), gives origin to emission signal enhancement coming from the sample, due to the surface plasmon located over such NPs (LSP, Localized Surface Plasmon). This effect has allowed the development of new spectroscopic techniques of high sensitivity, whose acronyms are SERS (Surface Enhanced Raman Scattering) and, SEF (Surface Enhanced Fluorescence) or MEF (Metal Enhanced Fluorescence). The intensification of the Raman or fluorescence signal of a molecule allows a greater sensitivity in its direction, being possible, additionally, to use such signals to get images of its spatial distribution in synthetic or biological samples. These techniques have multiple applications in the scope of Health Scientific area among which there are the development of drug delivery systems and the treatment of diseases such as cancer, AIDS or Alzheimer, being those techniques the ones used in the work. Mainly, due to its dielectric constant, the most used metals to produce NPs are silver and gold. The use of silver and gold nanostructures presents two great advantages: i) the molecules are easily adsorbed on metal surface without the need of functionalization or with a simple functionalization and ii) the LSPs of such NPs are resonant with lasers that emit at 532 nm and 785 nm respectively. Metal NPs can be modified to optimize its function, for instance, can be covered with a silicon layer forming nanostructures of “core-shell” type, that allow the enhancement of spectroscopic signal according to the thickness of the covering layer that separates the metal from the fluorophore. They can also be immobilized in the porous of certain material such as porous silicon (PSi), which is one of the mesoporous components presently used in nanotechnology. PSi is biocompatible and presents photoluminescence in visible region which allows registering the presence of non-fluorescent molecules immobilized in the surface of its nanoporous. Nevertheless, the existent handicap is due to the need of nanoporous functionalization in order to fix the majority of molecules...
Nanotechnology allows matter manipulation at nanometric level, size at which quantic effects are important. Considering molecular spectroscopy, specifically Raman and fluorescence spectroscopy, the use of metal nanoparticles (NPs), gives origin to emission signal enhancement coming from the sample, due to the surface plasmon located over such NPs (LSP, Localized Surface Plasmon). This effect has allowed the development of new spectroscopic techniques of high sensitivity, whose acronyms are SERS (Surface Enhanced Raman Scattering) and, SEF (Surface Enhanced Fluorescence) or MEF (Metal Enhanced Fluorescence). The intensification of the Raman or fluorescence signal of a molecule allows a greater sensitivity in its direction, being possible, additionally, to use such signals to get images of its spatial distribution in synthetic or biological samples. These techniques have multiple applications in the scope of Health Scientific area among which there are the development of drug delivery systems and the treatment of diseases such as cancer, AIDS or Alzheimer, being those techniques the ones used in the work. Mainly, due to its dielectric constant, the most used metals to produce NPs are silver and gold. The use of silver and gold nanostructures presents two great advantages: i) the molecules are easily adsorbed on metal surface without the need of functionalization or with a simple functionalization and ii) the LSPs of such NPs are resonant with lasers that emit at 532 nm and 785 nm respectively. Metal NPs can be modified to optimize its function, for instance, can be covered with a silicon layer forming nanostructures of “core-shell” type, that allow the enhancement of spectroscopic signal according to the thickness of the covering layer that separates the metal from the fluorophore. They can also be immobilized in the porous of certain material such as porous silicon (PSi), which is one of the mesoporous components presently used in nanotechnology. PSi is biocompatible and presents photoluminescence in visible region which allows registering the presence of non-fluorescent molecules immobilized in the surface of its nanoporous. Nevertheless, the existent handicap is due to the need of nanoporous functionalization in order to fix the majority of molecules...
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Tesis inédita de la Universidad Complutense de Madrid, Facultad de Farmacia, Departamento de Química Física II (Físico-Química Farmacéutica), leída el 17/06/2016