Smart bactericides, design, synthesis and characterization.

Preventing microbial resistance to antibiotics is one of the most important challenges of our times, because multiresistant microorganisms are increasingly being reported. An approach based on silver nanoparticles is promising, given that this type of particles has been proven to exhibit antimicrobial activity. In addition, green strategies would be desirable, in which harmful chemicals are replaced by natural products to generate nanoparticles. Specifically, tannic acid (a phenolic metabolite present in many plants) has been used in addition to silver, and Coppo E et al. (2014) report their antimicrobial effects against various types of bacteria, including Escherichia coli (bacteria used in the model). Several synthesis methods have been previously described in combination with characterization by Raman spectroscopy (Dadosh 2009; Cao et al. 2014). However, we have found out that it is essential that the tannic acid solution used in the synthesis is neutralized before adding it to the silver solution to obtain the desired nanoparticles in a green synthesis. We have characterized our nanoparticles by UV-Vis spectrophotometry, and measured their hydrodynamic size and electrostatic stability by dynamic light scattering, which revealed an average size of 10-12 nm and a Zeta potential below -30mV. We have measured the antimicrobial activity using the minimum inhibitory concentration method, which, according to our preliminary results, indicate that said nanoparticles have a high antibacterial power against E.coli Dh5-α at low concentrations of the order of (15-20) μg of nanoparticles/ml. Our goals are to further adjust the range of concentrations and determine what would be the optimum concentration to ensure permanent antibacterial activity. With all the aforementioned, it can be stated that this type of nanoparticles is a very interesting proposal for the challenge of microbial resistance to antibiotics

PEGylated versus non-PEGylated magnetic nanoparticles as camptothecin delivery system

This is an Open Access article under the terms of the Creative Commons Attribution License.Camptothecin (CPT; (S)-(+)-4-ethyl-4-hydroxy-1H-pyrano[3',4':6,7]indolizino[1,2-b]quinoline-3,14-(4H,12H)-dione) is a highly cytotoxic natural alkaloid that has not yet found use as chemotherapeutic agent due to its poor water-solubility and chemical instability and, as a consequence, no effective administration means have been designed. In this work, camptothecin has been successfully loaded into iron oxide superparamagnetic nanoparticles with an average size of 14 nm. It was found that surface modification of the nanoparticles by polyethylene glycol enables loading a large amount of camptothecin. While the unloaded nanoparticles do not induce apoptosis in the H460 lung cancer cell line, the camptothecin-loaded nanoparticle formulations exhibit remarkable proapoptotic activity. These results indicate that camptothecin retains its biological activity after loading onto the magnetic nanoparticles. The proposed materials represent novel materials based on naturally occurring bioactive molecules loaded onto nanoparticles to be used as chemotherapeutic formulations. The procedure seems apt to be extended to other active molecules extracted from natural products. In addition, these materials offer the potential of being further implemented for combined imaging and therapeutics, as magnetic nanoparticles are known to be multifunctional tools for biomedicine.This work was supported by Fundación Progreso y Salud, Consejería de Salud (PI0070) and Proyecto de Investigación de Excelencia de la Junta de Andalucía (P10-FQM-6615).Peer Reviewe

Microstructural Characterization of Silver Nanoparticles for Bioimaging Applications

Junta de Andalucía FQM-6615, PI0070, FQM31

Assessment by laser-induced breakdown spectroscopy of penetration depth in limestones of four nano-biocides based on silver/titanium nanoparticles

[Abstract]: Four biocidal treatments based on nanoparticles were designed and their penetration depths were char- acterized by laser-induced breakdown spectroscopy (LIBS) technique. This kind of biocidal nanoparticles are being studied to be employed in historic buildings and stone monuments due to their capability to inhibit the growth of biofoulings. The effectiveness of the treatment is related to the penetration depth of the nanoparticles in the limestone pore. For this reason, LIBS depth profiling was used in this work to characterize the diffusion of the nanoparticles in the limestone matrix and to compare the penetration depth of the different treatments. Four different nano-biocides based on silver/titanium dioxide nanopar- ticles were analysed by LIBS in limestone from Novelda quarry (Alicante, Spain). This limestone has been widely employed in both historical and contemporary buildings in Spain. The positive detection of the emission line of Ag at 338.289 nm was examined in the depth-related emission spectra as evidence of the presence of the silver nanoparticles and derived nanocomposites in the limestone matrix. The LIBS depth-profiles that were generated, showed a decrease of the Ag net signal with depth due to the diffusion of the nanoparticles in the limestone. Furthermore, the comparison of the in-depth sequences of spectra, and of the Ag depth profiles evidenced penetration differences between the nano-biocides which were explained by differences in the hydrodynamic diameter of the nanoparti- cles that would affect their diffusion in the limestone pore. The results of this assessment demonstrate the capability and potential of LIBS technique for the in-depth characterization of the nanoparticles and for the comparison of the effectiveness of nanoparticles biocidal treatments based on their penetration in the stone matrix

Nanoparticles applied to stone buildings

Proyecto Art-Risk, BIA2015-64878-RStone has been widely used as a construction material since ancient times, and its preservation is crucial in historical and contemporary buildings. Biodeterioration and other alterations cause damage in stone monuments which leads to the need for repeated actions. Nanotechnology is increasing the development of new products for construction and restoration, and new treatments based on nanoparticles have been developed for stone conservation, such as biocides or consolidants. These treatments avoid the disadvantages of traditional products, such as limewater for consolidation or quaternary ammonium salts as biocides and fulfil some of the requirements demanded by cultural heritage, i.e., effectiveness, compatibility with the stone and its aesthetic values, and durability. This manuscript reviews some of the main advances in the development and application of nanoparticles as consolidants and biocides to treat stone cultural heritage.Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de OlavideÁrea de laboratorios, Centro de inmuebles, obras e infraestructuras, Instituto Andaluz del Patrimonio HistóricoPreprin

Synergy achieved in silver-TIO2 nanocomposites for the inhibition of biofouling on limestone.

Biodeterioration of stone monuments is estimated to be as high as 20¿30% of the total degradation suffered by Cultural Heritage constructions. With regard to this problem, bactericidal treatments are mainly based on cleaning. These processes, while effective in the short term, require frequent reapplications increasing potential damages to the monument. Silver nanoparticles offer many advantages over traditionally employed products, such as their prolonged biocide efficacy and their low toxicity to humans and environment. The aim of this study was to evaluate the applicability and effectiveness of seven nanocomposite treatments based on titanium dioxide and/or silver nanoparticles to prevent biodeterioration of limestone monuments. These nanocomposites were characterized by UV¿Visible spectrophotometry, Dynamic Light Scattering and Electron Microscopy. To assess their bactericidal activity, accelerated weathering tests were performed on limestones from the quarry of Utrera, a source widely employed in such iconic monuments as the Cathedral of Seville (Spain). Furthermore, the samples of biopatina employed in our assays stemmed from the façades of historical buildings from Seville. Our results show that silver and titanium dioxide nanocomposites stabilized by citrate achieve a high biocide effect while maintaining color alterations at a low level.Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de OlavideInstituto de Ciencia de Materiales de SevillaPreprin

Procedimiento post-síntesis de modificación de la superficie de nanopartículas superparamagnéticas de óxidos de hierro

La presente invención se refiere a un procedimiento post-síntesis de modificación de la superficie de nanopartículas superparamagnéticas de óxidos de hierro con grupos hidroxilo, sin espaciador, a las nanopartículas de superficie modificada obtenidas por el mismo, así como el uso de estas nanopartículas de superficie modificada en terapia, diagnóstico y en técnicas de concentración y separación de muestras químicas y biológicas.Peer reviewedUniversidad Pablo de Olavide Consejo Superior de Investigaciones Científicas (España)B1 Patente sin examen previ

Nanopartículas metálicas funcionalizadas con el neuropéptido VIP y procedimiento de preparación

Nanopartículas metálicas funcionalizadas con el neuropéptido VIP y procedimiento de preparación. Constituye el objeto de la presente invención nanopartículas metálicas funcionalizadas con el neuropéptido VIP, así como el procedimiento de preparación de dichas nanopartículas. Las nanopartículas objeto de la presente invención presentan uniones selectivas de nanopartículas a péptidos en dos orientaciones posibles, grupo NH2 o grupo COOH. En esta última orientación, los péptidos si son reconocidos por los receptores de membranas celulares, lo que proporciona una herramienta que permite discernir efectos dependientes e independientes de receptor. El péptido empleado ha sido el VIP, mediante el cual se obtiene un amplio espectro de funciones biológicas, incluida inmunomodulación, actuando predominantemente como un potente anti-inflamatorio y un agente inhibidor de la respuesta del Th1 en el sistema inmunitario y emergiendo como un importante factor terapéutico para el tratamiento de enfermedades con componentes inflamatorias y autoinmunes.Universidad Pablo de Olavide, Universidad de Sevilla, Consejo Superior de Investigaciones Científicas (España), Fundación Reina Mercedes para la Investigación SanitariaA1 Solicitud de patentes con informe sobre el estado de la técnic