A New Porphyrin for the Preparation of Functionalized Water-Soluble Gold Nanoparticles with Low Intrinsic Toxicity

Altres ajuts: T.P. thanks the Generalitat de Catalunya for the AGAUR FI-DGR 2011 predoctoral grant.A potential new photosensitizer based on a dissymmetric porphyrin derivative bearing a thiol group was synthesized. 5-[4-(11-Mercaptoundecyloxy)-phenyl-10,15,20-triphenylporphyrin (PR-SH) was used to functionalize gold nanoparticles in order to obtain a potential drug delivery system. Water-soluble multifunctional gold nanoparticles GNP-PR/PEG were prepared using the Brust-Schiffrin methodology, by immobilization of both a thiolated polyethylene glycol (PEG) and the porphyrin thiol compound (PR-SH). The nanoparticles were fully characterized by transmission electron microscopy and 1H nuclear magnetic resonance spectroscopy, UV/Vis absorption spectroscopy, and X-ray photoelectron spectroscopy. Furthermore, the ability of GNP-PR/PEGs to induce singlet oxygen production was analyzed to demonstrate the activity of the photosensitizer. Cytotoxicity experiments showed the nanoparticles are nontoxic. Finally, cellular uptake experiments demonstrated that the functionalized gold nanoparticles are internalized. Therefore, this colloid can be considered to be a novel nanosystem that could potentially be suitable as an intracellular drug delivery system of photosensitizers for photodynamic therapy

Iron oxide nanoparticles functionalized with novel hydrophobic and hydrophilic porphyrins as potential agents for photodynamic therapy

The preparation of novel porphyrin derivatives and their immobilization onto iron oxide nanoparticles to build up suitable nanotools for potential use in photodynamic therapy (PDT) has been explored. To achieve this purpose, a zinc porphyrin derivative, ZnPR-COOH, has been synthesized, characterized at the molecular level and immobilized onto previously synthesized iron oxide nanoparticles covered with oleylamine. The novel nanosystem (ZnPR-IONP) has been thoroughly characterized by a variety of techniques such as UV-Vis absorption spectroscopy, fluorescence spectroscopy, X-ray photoloectron spectroscopy (XPS) and transmission electron microscopy (TEM). In order to probe the capability of the photosensitizer for PDT, the singlet oxygen production of both ZnPR-IONP and the free ligand ZnPR-COOH have been quantified by measuring the decay in absorption of the anthracene derivative 9,10-anthracenedipropionic acid (ADPA), showing an important increase on singlet oxygen production when the porphyrin is incorporated onto the IONP (ZnPR-IONP). On the other hand, the porphyrin derivative PR-TRIS3OH, incorporating several polar groups (TRIS), was synthesized and immobilized with the intention of obtaining water soluble nanosystems (PR-TRIS-IONP). When the singlet oxygen production ability was evaluated, the values obtained were similar to ZnPR-COOH/ZnPR-IONP, again much higher in the case of the nanoparticles PR-TRIS-IONP, with more than a twofold increase. The efficient singlet oxygen production of PR-TRIS-IONP together with their water solubility, points to the great promise that these new nanotools represent for PDT

A New Porphyrin for the Preparation of Functionalized Water-Soluble Gold Nanoparticles with Low Intrinsic Toxicity

A potential new photosensitizer based on a dissymmetric porphyrin derivative bearing a thiol group was synthesized. 5-[4-(11-Mercaptoundecyloxy)-phenyl-10,15,20-triphenylporphyrin (PR-SH) was used to functionalize gold nanoparticles in order to obtain a potential drug delivery system. Water-soluble multifunctional gold nanoparticles GNP-PR/PEG were prepared using the Brust-Schiffrin methodology, by immobilization of both a thiolated polyethylene glycol (PEG) and the porphyrin thiol compound (PR-SH). The nanoparticles were fully characterized by transmission electron microscopy and 1H nuclear magnetic resonance spectroscopy, UV/Vis absorption spectroscopy, and X-ray photoelectron spectroscopy. Furthermore, the ability of GNP-PR/PEGs to induce singlet oxygen production was analyzed to demonstrate the activity of the photosensitizer. Cytotoxicity experiments showed the nanoparticles are nontoxic. Finally, cellular uptake experiments demonstrated that the functionalized gold nanoparticles are internalized. Therefore, this colloid can be considered to be a novel nanosystem that could potentially be suitable as an intracellular drug delivery system of photosensitizers for photodynamic therapy. Keywords: drug delivery, gold nanoparticles, photodynamic therapy, photosensitizers, porphyrin

Water soluble, multifunctional antibody-porphyrin gold nanoparticles for targeted photodynamic therapy

Photodynamic therapy (PDT) is a treatment of cancer by which tumour cells are destroyed using reactive oxygen species produced by photosensitizers following activation with visible or near infrared light. Successful PDT depends on the solubility and the targeting ability of the photosensitizers. In this work, the synthesis of a porphyrin-based water soluble nanoparticle conjugate containing a targeting agent that recognizes the erbB2 receptor overexpressed on the surface of particular cancer cells is reported. The nanoparticle conjugates were synthesized following two different protocols, viz. a biphasic and a monophasic method, with the aim to determine which method yielded the optimal nanosystem for potential PDT applications. The nanoparticles were characterized using UV–Vis absorption and fluorescence spectroscopies together with transmission electron microscopy and zeta potential measurements; and their ability to produce singlet oxygen following irradiation was investigated following the decay in absorption of a singlet oxygen probe. The nanoparticles synthesized using the monophasic method were shown to produce the highest amount of singlet oxygen and were further functionalized with anti-erbB2 antibody to target the erbB2 receptors expressed on the surface of SK-BR-3 human breast cancer cells. The water soluble, antibody-porphyrin nanoparticle conjugates were shown to elicit targeted PDT of the breast cancer cells

Implementing Horizon Scanning as a tool for the strategic development of regulatory guidelines for nanotechnology-enabled health products

Strategic regulatory development is essential to ensure that new innovations in nanotechnology-enabled health products (NHPs) successfully reach the market and benefit patients. Currently, the lack of specific regulatory guidelines for NHPs is considered one of the primary causes of the so-called “valley of death” in these products, impacting both current and future advancements. In this study, we have implemented a methodology to anticipate key trends in NHP development and compare them with the current regulatory landscape applicable to NHPs. This methodology relies on Horizon Scanning, a tool commonly used by policymakers to foresee future needs and proactively shape a regulatory framework tailored to those needs. Through the application of this methodology, different trends in NHP have been identified, notably NHPs for drug delivery and dental applications. Furthermore, the most disruptive elements involve NHPs that are multicomposite and multifunctional, harnessing nano-scale properties to combine therapeutic and diagnostic purposes within a single product. When compared with the regulatory landscape, current regulations are gradually adapting to accommodate emerging trends, with specific guidelines being developed. However, for the most disruptive elements, multicomposite and multifunctional NHPs, their novelty still poses significant regulatory challenges, requiring a strategic development of guidelines by regulatory agencies to ensure their safe and effective integration into healthcare practices. This study underscores the importance of proactive regulatory planning to bridge the gap between NHP innovation and market implementation

Classification system for nanotechnology-enabled health products with both scientific and regulatory application

The lack of specific regulatory guidelines for nanotechnology-enabled health products (NHPs) is hampering development and patient access to these innovative technologies. Namely, there is an urgent need for harmonized regulatory definitions and classification systems that allow establishing a standardized framework for NHPs regulatory assessment. In this work, a novel classification system for NHPs is proposed. This classification can be applied for sorting nano-based innovations and regulatory guidelines according to the type of NHPs they address. Said methodology combines scientific and regulatory principles and it is based on the following criteria: principal mode of action, chemical composition, medical purpose and nanomanufacturing approach. This classification system could serve as a useful tool to sensor the state of the art of NHPs which is particularly useful for regulators to support strategy development of regulatory guidelines. Additionally, this tool would also allow manufacturers of NHPs to align their development plans with their applicable guidelines and standards and thus fulfill regulators expectations

Synthesis and in vitro phototoxicity of multifunctional Zn(II)meso-tetrakis(4-carboxyphenyl)porphyrin-coated gold nanoparticles assembled via axial coordination with imidazole ligands

Hypothesis Metalloporphyrins are extensively investigated for their ability to form reactive oxygen species and as potent photosensitisers for use in photodynamic therapy. However, their hydrophobicity generally causes solubility issues concerning in vivo delivery due to lack of distribution and low clearance from the body. Immobilising porphyrins on carriers, such as gold nanoparticles (GNP), can overcome some of these drawbacks. The mode of assembling the porphyrins to the carrier influences the properties of the resulting drug delivery systems. Experiments We describe the synthesis and characterisation of new porphyrin decorated water soluble GNP and we explore Zn-imidazole axial coordination as the mode of linking the porphyrin to the metallic core of the nanoparticles. Quantification of singlet oxygen production, toxicity in dark, cellular uptake by SK-BR-3 cells and phototoxicity have been assessed. Findings Axial coordination limits the number of porphyrins on the gold surface, reduces the formation of aggregates, and diminishes metal exchange in the porphyrin, all of which contribute to enhance the efficiency of singlet oxygen generation from the immobilised porphyrin. In vitro experiments on SK-BR-3 cells reveal a fast uptake followed by more than 80% cell death after irradiation with low doses of light

Nanodiagnostics to face SARS-CoV-2 and future pandemics : from an idea to the market and beyond

Altres ajuts: CERCA Programme/Generalitat de CatalunyaAltres ajuts: Consejo Superior de Investigaciones Científicas (CSIC) for the project "COVID19-122"The COVID-19 pandemic made clear how our society requires quickly available tools to address emerging healthcare issues. Diagnostic assays and devices are used every day to screen for COVID-19 positive patients, with the aim to decide the appropriate treatment and containment measures. In this context, we would have expected to see the use of the most recent diagnostic technologies worldwide, including the advanced ones such as nano-biosensors capable to provide faster, more sensitive, cheaper, and high-throughput results than the standard polymerase chain reaction and lateral flow assays. Here we discuss why that has not been the case and why all the exciting diagnostic strategies published on a daily basis in peer-reviewed journals are not yet successful in reaching the market and being implemented in the clinical practice

Synthesis and functionalization of nano- and micro-particles for sensing and therapy in living cells

[spa] El diseño y la preparación, mediante la utilización de procesos de biofuncionalización de micro / nanosistemas que puedan tener aplicación en células vivas es un tema de actualidad en campos como la Nanobiotecnología y la Nanomedicina. De este modo, en la presente tesis se ha estudiado el proceso de biofuncionalización de micropartículas de polisilicio, para actuar como etiquetas celulares, debido al interés que genera la posibilidad de poder etiquetar células vivas y así conocer el comportamiento de las células de manera individual. Sucesivamente, también se ha estudiado la preparación de quimiosensores de dos parámetros intracelulares (pH y calcio) basados en compuestos con capacidad de variar la intensidad de su fluorescencia, según cambios del medio. Concretamente, se ha trabajado en la síntesis e inmovilización de derivados del aminoantraceno en micropartículas de silicio como posibles candidatos para obtener microherramientas capaces de detectar cambios en el pH o en la concentración de calcio intracelulares. Por otro lado, la tesis también describe la preparación de nanosistemas para su aplicación en terapia fotodinámica. La terapia fotodinámica (PDT) se basa en el uso de moléculas específicas (fotosensibilizadores), que en presencia de luz (generalmente un láser), activan el proceso de la muerte celular debido a la formación de radicales libres de oxígeno. La combinación de la utilización de nanopartículas modificadas con un fotosensibilizador resulta un reto interesante que podría mejorar la terapia antitumoral, disminuyendo sus efectos secundarios. Concretamente, en la tesis se describe la preparación de nuevos fotosensibilizadores derivados de porfirinas, con el fin ser incorporados a nanopartículas de óxido de hierro y de oro. También se detalla el estudio de la capacidad de los nuevos nanosistemas obtenidos de producir oxígeno singlete como elemento inductor de la apoptosis celular, y resultados preliminares in vivo indican su potencial aplicación en PDT. Estos estudios, demuestran la posibilidad de dichos nanosistemas para ser usados en terapia fotodinámica. Por último, también se han sintetizado derivados de metalo-porfirinas como componentes de rotores moleculares.[eng] In the present thesis Supramolecular chemistry is exploited to approach applications in the area of Nanomedicine, and it is, focused on the design and preparation of different micro and nanotools for sensing and therapy, in living cells. Initially, the combination of silicon surface chemistry with the incorporation of bioactive molecules has been investigated in order to obtain a potentially microtool suitable for cell tagging. Furthermore, the design and synthesis of organic compounds as intracellular chemosensors was also explored. On the other hand, this report also includes the synthesis and characterization of dissymmetrical porphyrin derivatives and their subsequent incorporation to metal nanoparticles (gold and iron oxide) for their use in photodynamic therapy (PDT), due to their capacity to produce reactive oxygen species after irradiation, inducing the cell death. The preparation of novel metallo-porphyrins as components of molecular machines was also achieved. First, the formation of self-assembled monolayers (SAM) on polysilicon surfaces was investigated, using different silanes to obtain a functionalization protocol which can be easily repetitive and effective. Thus, three silanes with different functional groups, an aldehyde, an epoxide and an activated ester, have been tested to prepare a SAM and subsequently, prompting us to immobilize a bioactive molecule. Different parameters of the functionalization methodology have been examined, such as the silanization time, deposition method, the type of solvent and silane concentration. Once the SAM formation was optimized, the immobilization of the protein what germ agglutinin (WGA) was achieved, because its ability of cell membrane recognition. The WGA used, included a fluorescent dye (Texas red) to be able to characterize the immobilization of the protein on a silicon surface by fluorescence microscopy, and similar successful results were obtained in the three different silanes used. The same methodology (SAM formation and WGA immobilization) was subsequent applied in silicon encoded microparticles designed for tagging cells. Experiments using mouse embryos have been performed to determine the extracellular adhesion level of the encoded microparticles, resulting above 90 % in all cases. Proper immobilization of WGA protein was the key factor in cell labeling, because WGA recognizes specifically certain carbohydrates expressed in the external membrane (zona pellucida) of the embryo. Synthesis and immobilization of an aminoanthracene derivative as pH sensor was carried out, and its subsequent immobilization on silicon microparticles was achieved. Fluorescence spectroscopy measurements demonstrated that the aminoanthracene derivative immobilized on silicon microparticles could be a potential microtool for sense intracellular pH. Fluorescence spectroscopy experiments showed an important increase at acid pH, whereas from pH 7 to pH 12 the fluorescence emission was very low. On the other hand, aminoanthracene incorporating an aza-crown ether was also prepared as a possible candidate for calcium sensing. Preliminary studies using fluorescence spectroscopy, demonstrated a good selectivity for calcium in comparison with other cations such as magnesium, sodium and potassium. Dissymmetrical porphyrin derivatives have been synthesized and then immobilized on gold and iron oxide nanoparticles, obtaining water soluble metallic nanoparticles incorporating the photosensitizer. The capacity to produce singlet oxygen to induce the cell death following irradiation was investigated, resulting porphyrin immobilized gold or iron oxide nanoparticles. Thus, the prepared porphyrin derivatives and their corresponding nanotools exhibited a high formation of singlet oxygen, resulting nanotools potentially suitable for PDT. Otherwise, anti-erbB2 antibody, a specific antibody for a membrane receptor overexpressed in breast cancer cells, was immobilized onto water soluble porphyrin-gold nanoparticles. Preliminary experiments in a breast cancer cell line, demonstrated the capacity of the porphyrin-antibody-gold nanoparticle to produce the cell death following irradiation. Finally a metallo-porphyrins derivative was synthesized and characterize as a promising component for molecular rotors

Supramolecular chemistry for nanomedicine

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/46988Mimicking Nature, supramolecular chemistry represents the chemistry beyond the molecule, in view that intermolecular interactions constitute the driving force for the preparation of molecular and supramolecular assemblies, using the chemical information contained in molecular building blocks. Upon molecular recognition between discrete units, chemical processes such as self-assembly and self-organisation start operating, and are the leading processes to build up supramolecular aggregates and materials. When those materials have dimensions on the nanometric scale, a recently emerging scientific discipline is defined, Nanoscience. Nanomaterials are promising tools for many applications, and their use in biomedical and clinical applications defines the so-called Nanomedicine. In this review we present a few selected examples of nanomaterials designed for therapeutical purposes, emphasizing the importance of the preparation methodology in terms of their therapeutical use