Gold, Silver and Platinum Nanoparticles: From New Synthetic Routes to Sensing, Catalysis and Bio-Applications

Gold, Silver and Platinum metallic nanoparticles have emerged as powerful tools with a wide array of applications in different fields, such as biomedicine, catalysis, and environmental sciences. The modification of nanoparticles´ metal composition, size, and shape lead to totally different properties of the nanomaterial. This tunable versatility is responsible for the vast array of applications of nanomaterials that affects the way we live now and will in the future. The project of this PhD thesis was designed with the main objective of developing new green and sustainable Nano-synthetic methodologies to obtain new Nano-particles for biomedical, chemical and environmental applications. In Chapter two it is described the chemical synthesis of new gold and silver functionalised nanoparticles, engineered to achieve naked-eye detection of a toxic metal ion, namely mercury, in aqueous and non-aqueous liquids. Such achievements were published in the journal Chemistry Open of Wiley, and also highlighted as journal front cover (IF 2.938). In chapters three and four the synthesis of new platinum nanoparticles with spherical or dendritic shapes to be used as catalysts is described. In addition, the catalytic applications were assessed in the reduction of p-nitrophenol in aqueous media. Moreover, our system shows catechol-oxidase activity, which allows oxidation of amino acid L-3,4-dihydroxyphenylalanine, a drug to treat Parkinson disease. The results were published in the Scientific Reports (IF 4.122), and in the Nano Research (IF 7.994), from Springer Nature editorial. In chapter five a new methodology for the preparation of gold nanorods covered with a mesoporous silica shell is described. The new systems were conjugated with doxorubicin and methylene blue and studied as new drug nanocarriers. Properties were successfully tested against Human Breast Adenocarcinoma (MCF7) cells and Gram-negative and Gram-positive bacteria as new antibiotics to fight microbial resistance. Results are presented in a manuscript under revision

the role of adenosine monophosphate

Funding Information: The authors acknowledge financial support from the European Innovation Council (Horizon 2020 Project: 965018—BIOCELLPHE), the MCIN/AEI/10.13039/501100011033 (grant PID2019-108954RB-I00), the FSE (“El FSE invierte en tu futuro”), the Xunta de Galicia/FEDER (grant GRC ED431C 2020/09), the European Regional Development Fund (ERDF), and the Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior, FCT-MCTES (grants UIDB/50006/2020, UIDP/50006/2020 and Met4cat, EXPL/QUI-COL/0263/2021). J. F.-L. thanks FCT-UNL for the research contract through the Program DL 57/2016−Norma Transitória. S. N. thanks the FCT-MCTES Portugal for her doctoral grant associated with the Chemistry PhD program (SFRH/BD/144618/2019). C. F.-L. acknowledges Xunta de Galicia for a predoctoral scholarship (Programa de axudas á etapa predoutoral). C. L., A. F. L., S. N and J. F. L thank the financial support of the PROTEOMASS Scientific Society (Portugal) (General Funding Grants 2022-2023) and the Associate Laboratory Research Unit for Green Chemistry-Clean Processes and Technologies - LAQV/REQUIMTE. This work was carried out in part through the use of the INL Advanced Electron Microscopy, Imaging and Spectroscopy Facility and Microscopy Facility at CACTI (Universidade de Vigo). The authors thank Dr. Jamila Djafari for her assistance with the graphical abstract. Publisher Copyright: © 2023 The Royal Society of Chemistry.The seed-mediated growth of gold nanostructures is known to be strongly dependent not only on the gold seed nanocrystal structure but also on the presence of different additives that may influence the morphology, and therefore the crystalline structure of the final nanoparticle. Among the different additives or capping ligands, biomolecules are an interesting family due to their potential biomedical applications such as drug delivery, bioimaging, biosensing, phototherapy, and antimicrobial activities. Here, we develop a seed-mediated strategy for synthesizing uniform Au nanostars with tuneable optical properties which involves adenosine monophosphate (AMP) as a capping ligand. The experimental data reveal the key role of AMP not just providing colloidal stability and directing the reduction of the gold precursor via complexation but also mediating the anisotropic growth of the Au seeds via its selective adsorption on the different crystalline facets of Au nanoparticles. These observations agree with theoretical simulations carried out using molecular dynamics and density functional theory (DFT) calculations. Interestingly, the obtained Au nanostars showed high thermal stability as well as colloidal stability in polar organic solvents, which allowed their direct silica coating via the Stöber method. Importantly, we also explored the mimic enzymatic activity of the resulting gold nanostars and observed a superior catalytic activity compared with other gold nanoparticles reported in the literature.publishersversionpublishe

Copper(i) as a reducing agent for the synthesis of bimetallic PtCu catalytic nanoparticles

Funding Information: This work received financial support from PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the projects UIDB/50006/2020 and UIDP/50006/2020. S. N., C. L., J. L. C., A. F. L., and J. F. L. are thankful for the financial support from national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through project Met4Cat, EXPL/QUI-COL/0263/2021. This work was supported by the Spanish Government and the Spanish National Research Council (CSIC) (project PIE 201980E081). We thank the financial support by the PROTEOMASS Scientific Society (Portugal) (General Funding Grant 2022). S. N. thanks FCT/MCTEC (Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) Portugal for her doctoral grant associated with the Chemistry PhD program (SFRH/ BD/144618/2019). J. F. L. thanks FCT for the research contract through the Program DL 57/2016–Norma Transitória. A. F. L., J. F. L., S. N., J. L. C., and C. L. thank FCT/MCTES (Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) for the national funds received through the project SiSi4Bacter PTDC/QUI-COL/1517/2020. This work was carried out in part through the use of the INL user facilities. The authors thank Dr Jamila Djafari for the conceptualization and design of the graphical abstract. We also thank Ramiro Martínez from Novozymes for the gift of enzymes. Funding Information: This work received financial support from PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the projects UIDB/50006/2020 and UIDP/50006/2020. S. N., C. L., J. L. C., A. F. L., and J. F. L. are thankful for the financial support from national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through project Met4Cat, EXPL/QUI-COL/0263/2021. This work was supported by the Spanish Government and the Spanish National Research Council (CSIC) (project PIE 201980E081). We thank the financial support by the PROTEOMASS Scientific Society (Portugal) (General Funding Grant 2022). S. N. thanks FCT/MCTEC (Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) Portugal for her doctoral grant associated with the Chemistry PhD program (SFRH/ BD/144618/2019). J. F. L. thanks FCT for the research contract through the Program DL 57/2016-Norma Transitória. A. F. L., J. F. L., S. N., J. L. C., and C. L. thank FCT/MCTES (Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) for the national funds received through the project SiSi4Bacter PTDC/QUI-COL/1517/2020. This work was carried out in part through the use of the INL user facilities. The authors thank Dr Jamila Djafari for the conceptualization and design of the graphical abstract. We also thank Ramiro Martínez from Novozymes for the gift of enzymes. Publisher Copyright: © 2023 RSCThis work investigates the potential utilization of Cu(i) as a reducing agent for the transformation of the platinum salt K2PtCl4, resulting in the production of stable nanoparticles. The synthesized nanoparticles exhibit a bimetallic composition, incorporating copper within their final structure. This approach offers a convenient and accessible methodology for the production of bimetallic nanostructures. The catalytic properties of these novel nanomaterials have been explored in various applications, including their use as artificial metalloenzymes and in the degradation of dyes. The findings underscore the significant potential of Cu(i)-mediated reduction in the development of functional nanomaterials with diverse catalytic applications.publishersversionepub_ahead_of_prin

Synthesis and Structural Characterization of Branched Bimetallic AuPd Nanoparticles with a Highly Tunable Optical Response

Funding Information: This work received financial support from Portugal national funds [Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior (FCT/MCTES)] through the Projects UIDB/50006/2020 and UIDP/50006/2020. Silvia Nuti, Carlos Lodeiro, José-Luis Capelo-Martinez, Adrián Fernández-Lodeiro, and Javier Fernández-Lodeiro thank the financial support from national funds (FCT/MCTES) through Project Met4Cat (EXPL/QUI-COL/0263/2021). The authors thank the financial support by the PROTEOMASS Scientific Society (Portugal) (General Funding Grant 2023). The authors acknowledge funding from the European Union’s Horizon 2020 Research and Innovation Program under Grant 823717-ESTEEM3, and Ana B. Hungría thanks the financial support from Junta de Andalucía Project P20_00968. Silvia Nuti thanks FCT/MCTEC (Portugal) for her doctoral grant associated with the chemistry Ph.D. program (SFRH/BD/144618/2019). Javier Fernández-Lodeiro thanks FCT for the research contract through the Program DL 57/2016-Norma Transitória. The work was carried out partially through the INL User Facilities (Braga, Portugal) and the Electron Microscope Division (DME) of the Servicios Centrales de Investigación Científica y Tecnológica (SC-ICYT) at Cadiz University (Cadiz, Spain). The authors thank Dr. Jamila Djafari for the assistance with the design of the graphical abstract. Funding Information: This work received financial support from Portugal national funds [Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior (FCT/MCTES)] through the Projects UIDB/50006/2020 and UIDP/50006/2020. Silvia Nuti, Carlos Lodeiro, José-Luis Capelo-Martinez, Adrián Fernández-Lodeiro, and Javier Fernández-Lodeiro thank the financial support from national funds (FCT/MCTES) through Project Met4Cat (EXPL/QUI-COL/0263/2021). The authors thank the financial support by the PROTEOMASS Scientific Society (Portugal) (General Funding Grant 2023). The authors acknowledge funding from the European Union’s Horizon 2020 Research and Innovation Program under Grant 823717-ESTEEM3, and Ana B. Hungría thanks the financial support from Junta de Andalucía Project P20_00968. Silvia Nuti thanks FCT/MCTEC (Portugal) for her doctoral grant associated with the chemistry Ph.D. program (SFRH/BD/144618/2019). Javier Fernández-Lodeiro thanks FCT for the research contract through the Program DL 57/2016–Norma Transitória. The work was carried out partially through the INL User Facilities (Braga, Portugal) and the Electron Microscope Division (DME) of the Servicios Centrales de Investigación Científica y Tecnológica (SC-ICYT) at Cadiz University (Cadiz, Spain). The authors thank Dr. Jamila Djafari for the assistance with the design of the graphical abstract. Publisher Copyright: © 2023 The Authors. Published by American Chemical Society.Bimetallic nanostructures composed of gold (Au) and palladium (Pd) have garnered increased interest for their applications in heterogeneous catalysis. This study reports a simple strategy for manufacturing Au@Pd bimetallic branched nanoparticles (NPs), which offer a tunable optical response, using polyallylamine-stabilized branched AuNPs as template cores for Pd overgrowth. The palladium content can be altered by manipulating the concentration of PdCl42- and ascorbic acid (AA) that are injected, which permit an overgrowth of the Pd shell up to ca. 2 nm thick. The homogeneous distribution of Pd at the surfaces of Au NPs can be carried out regardless of their size or branching degree, which allows for an adjustment of the plasmon response in the near-infrared (NIR) spectral range. As a proof of concept, the nanoenzymatic activity of pure gold and gold-palladium NPs was compared, exploring their peroxidase-like activity in the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB). The bimetallic AuPd NPs demonstrate an increase in the catalytic properties attributed to the presence of palladium at the surface of gold.publishersversionpublishe

Synthesis of mesoporous silica coated gold nanorods loaded with methylene blue and its potentials in antibacterial applications

Funding Information: Funding: We thank the financial support by the PROTEOMASS Scientific Society (Portugal) (General Funding Grant 2019–2020), as well as the Associate Laboratory Research Unit for Green Chemistry— Clean Processes and Technologies—LAQV-REQUIMTE financed by national funds from FCT/MEC (UIDB/04077/2020) and co-financed by the ERDF under the PT2020 Partnership Agreement (POCI-01-0145-FEDER—007265). J.D.; A.F.-L.; C.L.; J.F.-L. and J.L.C.-M. thanks to the FCT-MEC the research grant SiSi4Bacter (PTDC/QUI-COL/1517/2020). J.F.-L. thank FCT/MEC (Portugal) the junior researcher contract under DL57 pro-gramme. J.D. thanks the Project PTDC/QEQ-MED/2118/2014 for her researcher contract. A.F.-L. thanks the FCT-MEC Portugal for his doctoral grant associated with the Green Chemistry PhD. Program (SFRH/BD/52528/2014) and the PROTEOMASS Scientific Society Postdoctoral grant during August 2019–March 2021. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.In this work, the successful preparation and characterization of gold nanorods (AuNRs) coated with a mesoporous silica shell (AuNRs@Simes) was achieved. Conjugation with methylene blue (MB) as a model drug using ultrasound-stimulated loading has been explored for further application in light-mediated antibacterial studies. Lyophilization of this conjugated nanosystem was analyzed using trehalose (TRH) as a cryogenic protector. The obtained stable dry formulation shows potent antimicrobial activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria after a simple post-treatment irradiation method with a red laser during a short time period.publishersversionpublishe

Exploring the Control in Antibacterial Activity of Silver Triangular Nanoplates by Surface Coating Modulation

In the present work, the synthesis and characterization of silver triangular nanoplates (AgNTs) and their silica coating composites are reported. Engineering control on the surface coating has demonstrated the possibility to modulate the antibacterial effect. Several AgNT-coated nanomaterials, such as PVP (Polyvinylpyrrolidone) and MHA (16-mercaptohexadecanoic acid) as a stable organic coating system as well as uniform silica coating (≈5 nm) of AgNTs, have been prepared and fully characterized. The antibacterial properties of the systems reported, organic (MHA) and inorganic (amine and carboxylic terminated SiO2) coating nanocomposites, have been tested on Gram-positive and Gram-negative bacteria strains. We observed that the AgNTs' organic coating improved antimicrobial properties when compared to other spherical silver colloids found in the literature. We have also found that thick inorganic silica coating decreases the antimicrobial effect, but does not cancel it. In addition, the effect of surface charge in AgNTs@Si seems to play a crucial role toward S. aureus ATCC 25923 bacteria, obtaining MIC/MBC values compared to the AgNTs with an organic coating

BIM aplicado al patrimonio cultural

La asociación buildingSMART tiene como principal objetivo fomentar la eficacia en el sector de la construcción a través del uso de estándares abiertos de interoperabilidad con la metodología BIM (Building InformationMode-ling). Para ello, cuenta con una estructura de grupos de trabajo a nivel internacional para abordar diferentes cues-tiones al respecto. Sin embargo, en el ámbito del Patrimonio Cultural, no existe en la actualidad una aproximación internacional sobre el uso de BIM, y es por lo que buildingSMART Spanish Chapter ha puesto en marcha un grupo de trabajo abierto, denominado LEGEND–HBIM, y que está centrado en BIM aplicado al Patrimonio Cultural. De este modo, buildingSMART Spanish Chapter continua la laborde promover el uso de la metodología BIM a través de guías como esta, que supone una continuación de las guías uBIM publicadas en el año 2014

<em>N</em><sup>1</sup>-((1<em>H</em>-Indazol-5-yl)methylene)-<em>N</em><sup>2</sup>-(2-((2-((2-(((1<em>H</em>-indazol-6-yl)methylene)amino)ethyl)amino)ethyl)amino)ethyl)ethane-1,2-diamine

One novel molecular emissive probe <strong>L</strong> has been synthesized by classical Schiff-base reaction between 1H-indazole-6-carboxaldehyde<strong> </strong>and tetraethylenepentamine. The structure of compound <strong>L</strong> was confirmed by melting point, elemental analysis, ESI-MS spectrometry and by IR and <sup>13</sup>C-NMR and <sup>1</sup>H-NMR spectroscopy

Adenosine-Monophosphate-Assisted Homogeneous Silica Coating of Silver Nanoparticles in High Yield

International audienceIn this study, we propose a novel approach for the silica coating of silver nanoparticles based on surface modification with adenosine monophosphate (AMP). Upon AMP stabilization, the nanoparticles can be transferred into 2-propanol, promoting the growth of silica on the particle surfaces through the standard Stöber process. The obtained silica shells are uniform and homogeneous, and the method allows a high degree of control over shell thickness while minimizing the presence of uncoated NPs or the negligible presence of core-free silica NPs. In addition, AMP-functionalized AgNPs could be also coated with a mesoporous silica shell using cetyltrimethylammonium chloride (CTAC) as a template. Interestingly, the thickness of the mesoporous silica coating could be tightly adjusted by either the silica precursor concentration or by varying the CTAC concentration while keeping the silica precursor concentration constant. Finally, the influence of the silica coating on the antimicrobial effect of AgNPs was studied on Gram-negative bacteria (R. gelatinosus and E. coli) and under different bacterial growth conditions, shedding light on their potential applications in different biological environments

Adenosine Monophosphate as Shape-inducing Agent: The Case of Gold Nanostars

The seed-mediated growth of gold nanostructures is known to be intensely dependent on the gold seed nanocrystal structure but also in the presence of different additives that may influence the morphology and, therefore, the crystalline structure of the final nanoparticle. Among the different additives or capping ligands, biomolecules are an exciting family due to their potential biomedical applications, such as drug delivery, bioimaging, biosensing, phototherapy, and antimicrobial activities. Here, we develop a seed-mediated strategy for synthesizing uniform Au nanostars with tuneable optical properties that involve adenosine monophosphate (AMP) as a capping ligand. The experimental data reveal the key role of AMP, not just providing colloidal stability and directing the reduction of the gold precursor via complexation but also mediating the anisotropic growth of the Au seeds via its selective adsorption on the different crystalline facets of Au nanoparticles. These observations agree with theoretical simulations carried out using molecular dynamics and density functional theory (DFT) calculations. Interestingly, the obtained Au nanostars showed high thermal and colloidal stability in polar organic solvents, which allowed their direct silica coating via the Stöber method. Importantly, we also explored the mimic enzymatic activity of the resulting gold nanostars and observed a superior catalytic activity compared with the other gold nanoparticles reported in the literature