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The aim of the present research is to analyze thermophysical and tribological properties of PAO4 nanolubricants containing functionalized (GO-polyethyleneimine-oleic acid, GO-PEI-OA) and non-functionalized (GO) graphene oxide. Nanodispersions of these NPs were prepared, observing a better stability for the GO-PEI-OA nanolubricants. As for the tribological properties, significant improvements in coefficient of friction were obtained comparing with the base oil, being 28% for GO-PEI-OA (0.10 wt%). Concerning the anti-wear behavior, better results were obtained for GO-PEI-OA nanolubricants (0.15 wt%) with improvements of about 27%, 54% and 60% for the diameter, depth, and area of the wear track, respectively. Finally, Raman spectroscopy and surface roughness measurements were used to identify the tribological mechanisms of tribofilm formation and repairing.

The present study explored the utilization of Rugulopteryx okamurae (RO), an invasive brown seaweed, as a renewable raw material for plastic materials based on biopolymer blends. The goal of this study was to improve the previously observed poor mechanical properties of materials based on single biopolymer RO. To enhance these properties, two polymers with distinct hydrophobicities were incorporated into the formulation of different blends: hydrophobic polycaprolactone (PCL) and hydrophilic acylated soy protein isolate (SPIa). SPIa was derived from soy protein through a chemical modification process, introducing hydrophilic carboxyl groups. The addition of PCL significantly strengthened the blend, increasing the storage modulus (E′1 Hz) from ~ 110 to ~ 250 MPa. Conversely, SPIa incorporation resulted in softening, with E′ values around 40 MPa. Both additives enhanced deformability proportionally to their concentrations, with SPIa exhibiting notably higher deformability, reaching a maximum deformation of ~ 23% for a RO/SPIa ratio of 25/75. In summary, the study demonstrates the feasibility of producing environmentally friendly blend materials based on RO, tailored for specific applications by incorporating suitable additives into the formulation. Therefore, PCL is recommended for applications susceptible to moisture effects, such as packaging, while SPIa is suggested for highly absorbent applications such as personal care or horticulture.

BACKGROUND: Phycocyanobilin (PCB) is an open-chain blue tetrapyrrole chromophore of C-phycocyanin (C-PC), a major chromoprotein derived from the cyanobacterium Arthrospira platensis having numerous health-promoting effects. Relying on the ability of PCB to attach to the sulfhydryl group of proteins, we propose a new method for covalent attachment of PCB to bovine serum albumin (BSA) as a means of its functionalization. RESULTS: Traut's reagent (TR, 2-iminothiolane), modifying lysine residues, was used to optimize the introduction of sulfhydryl groups in BSA. A higher degree of BSA thiolation by TR induces more profound alterations of its structure, resulting in minor oligomerization and aggregation. A 50-fold molar excess of TR was found to be the optimal, balancing thiolation level and adverse effect on protein structure. PCB was covalently attached to newly introduced sulfhydryl groups at pH 9 at 20-fold PCB/BSA ratio. An increase in the TR/BSA molar ratio leads to increased efficiency of PCB conjugation with thiolated BSA. Compared to native BSA, BSA–PCB conjugate binds quercetin with similar affinity but has higher antioxidant activity and increased oxidative stability. CONCLUSIONS: PCB-modified BSA could serve as a stable, food-compatible carrier of bioactive PCB, but also bind other ligands that would be protected from oxidative damage due to the high antioxidant potential of covalently bound PCB. Thiolation by TR is, at the same time, a simple method for the covalent functionalization of virtually any protein by bioactive PCB or for obtaining PCB-based fluorescent probes.

Plant viral nanoparticles (VNPs) have become an attractive platform for the development of novel nanotools in the last years because of their safety, inexpensive production, and straightforward functionalization. Turnip mosaic virus (TuMV) is one example of a plant-based VNP used as a nanobiotechnological platform either as virions or as virus-like particles (VLPs). Their functionalization mainly consists of coating their surface with the molecules of interest via chemical conjugation or genetic fusion. However, because of their limitations, these two methods sometimes result in non-viable constructs. In this paper, we applied the SpyTag/SpyCatcher technology as an alternative for the functionalization of TuMV VLPs with peptides and proteins. We chose as molecules of interest the green fluorescent protein (GFP) because of its good traceability, as well as the vasoactive intestinal peptide (VIP), given the previous unsuccessful attempts to functionalize TuMV VNPs by other methods. The successful conjugation of VLPs to GFP and VIP using SpyTag/SpyCatcher was confirmed through Western blot and electron microscopy. Moreover, the isopeptide bond between SpyTag and SpyCatcher occurred in vivo in co-agroinfiltrated Nicotiana benthamiana plants. These results demonstrated that SpyTag/SpyCatcher improves TuMV functionalization compared with previous approaches, thus implying the expansion of the application of the technology to elongated flexuous VNPs., Unión Europea, Ministerio de Universidades (España), Comunidad de Madrid, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Universidad Complutense de Madrid (UCM), Depto. de Genética, Fisiología y Microbiología, Fac. de Ciencias Biológicas, TRUE, pub

Keratin is a largely available protein that can be obtained from the ca. 3 million tons of feathers that the European poultry industry produces as a side-stream. Here, the functionalization of keratin from poultry feathers was evaluated using a one- versus two-stage process using two functionalization agents (succinic anhydride-SA and ethylene dianhydride-EDTAD). The functionalization resulted in the keratin having improved liquid swelling capacities, reaching up to 400%, 300%, and 85% increase in water, saline, and blood, respectively, compared to non-functionalized keratin. The highest swelling was obtained for samples functionalized with EDTAD (one-stage process), while the highest saline uptake was noted for samples processed with 25 wt% SA (two-stage process). Swelling kinetics modeling indicated that the water uptake by the functionalized samples takes place in two steps, and the EDTAD samples showed the highest diffusivity. It is demonstrated that the one-stage functionalization of keratin utilizing EDTAD results in better performance than two-stages, which allows for resource-saving and, thereby, protecting the environment. The results show some potential for the keratin to be utilized as liquid absorbent materials in water, saline, and blood uptake applications. Using keratin from side-streams is an advantage from a sustainability perspective over biomacromolecules that need to be extracted from virgin biomass., QC 20230309

RESEARCHER ID M-3378-2014 (María Vallet Regí) ORCID 0000-0002-6104-4889 (María Vallet Regí), Bioceramics for bone tissue regeneration, local drug delivery and nanomedicine, are receiving growing attention by the biomaterials scientific community. The design of bioceramics with improved surface properties able to overcome clinical issues is a great scientific challenge. Zwitterionization of surfaces has arisen as a powerful alternative in the design of biocompatible bioceramics capable to inhibit bacterial and non-specific protein adsorption, which opens up new insights into the biomedical applications of these materials. This manuscript reviews the different approaches reported up to date for the synthesis and characterization of zwitterionic bioceramics with potential clinical applications. Statement of Significance Zwitterionic bioceramics are receiving growing attention by the biomaterials scientific community due to their great potential in bone tissue regeneration, local drug delivery and nanomedicines. Herein, the different strategies developed so far to synthesize and characterize zwitterionic bioceramics with potential clinical applications are summarized. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved., Ministerio de Economía y Competitividad (MINECO), Agening Network of Excellence, Depto. de Química en Ciencias Farmacéuticas, Fac. de Farmacia, TRUE, pub

Keratin is a largely available protein that can be obtained from the ca. 3 million tons of feathers that the European poultry industry produces as a side-stream. Here, the functionalization of keratin from poultry feathers was evaluated using a one- versus two-stage process using two functionalization agents (succinic anhydride-SA and ethylene dianhydride-EDTAD). The functionalization resulted in the keratin having improved liquid swelling capacities, reaching up to 400%, 300%, and 85% increase in water, saline, and blood, respectively, compared to non-functionalized keratin. The highest swelling was obtained for samples functionalized with EDTAD (one-stage process), while the highest saline uptake was noted for samples processed with 25 wt% SA (two-stage process). Swelling kinetics modeling indicated that the water uptake by the functionalized samples takes place in two steps, and the EDTAD samples showed the highest diffusivity. It is demonstrated that the one-stage functionalization of keratin utilizing EDTAD results in better performance than two-stages, which allows for resource-saving and, thereby, protecting the environment. The results show some potential for the keratin to be utilized as liquid absorbent materials in water, saline, and blood uptake applications. Using keratin from side-streams is an advantage from a sustainability perspective over biomacromolecules that need to be extracted from virgin biomass.

Mimicking bone extracellular matrix (ECM) is paramount to develop novel biomaterials for bone tissue engineering. In this regard, the combination of integrin-binding ligands together with osteogenic peptides represents a powerful approach to recapitulate the healing microenvironment of bone. In the present work, we designed polyethylene glycol (PEG)-based hydrogels functionalized with cell instructive multifunctional biomimetic peptides (either with cyclic RGD-DWIVA or cyclic RGD-cyclic DWIVA) and cross-linked with matrix metalloproteinases (MMPs)-degradable sequences to enable dynamic enzymatic biodegradation and cell spreading and differentiation. The analysis of the intrinsic properties of the hydrogel revealed relevant mechanical properties, porosity, swelling and degradability to engineer hydrogels for bone tissue engineering. Moreover, the engineered hydrogels were able to promote human mesenchymal stem cells (MSCs) spreading and significantly improve their osteogenic differentiation. Thus, these novel hydrogels could be a promising candidate for applications in bone tissue engineering, such as acellular systems to be implanted and regenerate bone or in stem cells therapy. Moreover, the engineered hydrogels were able to promote human mesenchymal stem cells (MSCs) spreading and significantly improve their osteogenic differentiation. Thus, these novel hydrogels could be a promising candidate for applications in bone tissue engineering, such as acellular systems to be implanted and regenerate bone or in stem cells therapy., Peer Reviewed, Postprint (published version)

Green, black, rooibos, and hibiscus tea (GT, BT, RT, and HT) aqueous extracts were prepared and characterized in terms of total flavonoids (TFC) and total phenolic (TPC) contents and antioxidant and antimicrobial activities. BT has the highest, while HT has the lowest TFC (1213 vs. 415 mg l–1), while the extracts’ TPCs (2283 – 7251 mg l–1) decreased in the following order: BT > GT > RT > HT. Their antioxidant activities of 78.1 – 93.1% and 97.8 – 100% were determined according to DPPH and ABTS methods, respectively. BT and especially GT aqueous extracts possessed mild effects against several microorganisms. All examined extracts have an affinity for dyeing wool, cellulose acetate, polyamide, and cotton, which is proven by the color strength values of 1.65–19.12. Wool, polyacrylonitrile, polyester, polyamide, cotton, and cellulose acetate functionalized with GT aqueous extract inhibited the growth of S. aureus and E. coli, while polyacrylonitrile and cotton also inhibited the growth of E. faecalis, and C. albicans, respectively. Wide inhibition zones for S. aureus were observed for fabrics functionalized with BT aqueous extract. Generally, the investigated fabrics showed very high (81.60 – 100%) ABTS radical scavenging ability independent of the extract used. TPCs have good linear correlations with the antioxidant activities of wool and polyacrylonitrile determined by the DPPH method. Fabrics with different chemical compositions dyed and/or functionalized with GT or BT aqueous extracts can be used to produce high-valueadded medical textiles with therapeutic, prophylactic, and protective functions. They can find potential applications in wound treatment, especially in skin wounds that are susceptible to infection with S. aureus. Moreover, wool and cotton functionalized with GT or BT aqueous extract can also be considered for use in disposable medical textiles like bandages and gauze used in the wound-healing process.

Functionalizing molecules through the selective cleavage of carbon-carbon bonds is an attractive approach in synthetic chemistry. Despite recent advances in both transition-metal catalysis and radical chemistry, the selective cleavage of inert Csp3-Csp3 bonds in hydrocarbon feedstocks remains challenging. Examples reported in the literature typically involve substrates containing redox functional groups or highly strained molecules. In this article, we present a straightforward protocol for the cleavage and functionalization of Csp3-Csp3 bonds in alkylbenzenes using photoredox catalysis. Our method employs two distinct bond scission pathways. For substrates with tertiary benzylic substituents, a carbocation-coupled electron transfer mechanism is prevalent. For substrates with primary or secondary benzylic substituents, a triple single-electron oxidation cascade is applicable. Our strategy offers a practical means of cleaving inert Csp3-Csp3 bonds in molecules without any heteroatoms, resulting in primary, secondary, tertiary, and benzylic radical species.

Advanced materials are among the prime drivers for technological revolutions and transformation in quality of lives. Over time, several modification techniques have emerged enabling development of novel materials with extraordinary features. The present review aims to introduce various promising chemical and physical surface modification techniques instrumental for tailoring the characteristics of thin films and membranes. Meticulous discussions are provided over chemical vapor deposition (CVD) techniques evolved for addressing the demands for materials with desired functionalities. Also, essential criteria for the selection of substrates, modifying and precursor materials for an effective CVD modification are elaborated. Investigations are extended to unraveling the role of various process parameters on the quality and properties of deposition. Special attention is paid to the significance and performance of CVD-based membranes and thin films for industrial applications ranging from desalination and water treatment to energy and environment, biomedical and life science as well as packaging. The goal has been to establish a scientific platform for a timely tracking of the prevailing trends in exploitation of CVD techniques and highlighting the unexplored opportunities. This also helps in identification of the scientific and technical gaps and setting directions for further progress in the fields of thin films and membranes.

Cellulose is the most abundant renewable polymer on Earth and can be obtained from several different sources, such as trees, grass, or biomass residues. However, one of the issues is that not all the fractionation processes are eco-friendly and are essentially based on cooking the lignocellulose feedstock in a harsh chemical mixture, such as NaOH + Na2S, and water, to break loose fibers. In the last few years, new sustainable fractionation processes have been developed that enable the obtaining of cellulose fibers in a more eco-friendly way. As a raw material, cellulose’s use is widely known and established in many areas. Additionally, its products/derivatives are recognized to have a far better environmental impact than fossil-based materials. Examples are textiles and packaging, where forest-based fibers may contribute to renewable and biodegradable substitutes for common synthetic materials and plastics. In this review, some of the main structural characteristics and properties of cellulose, recent green extraction methods/strategies, chemical modification, and applications of cellulose derivatives are discussed.

Enzymatic one-pot synthesis procedures in a one-step and two-step monomers addition were developed to obtain poly(glycerol adipate) macromers with methacrylate end-functional groups under the presence of 1 and 3 wt% of Candida antarctica lipase B (CALB). Glycerol, divinyl adipate, and vinyl methacrylate were enzymatically reacted (vinyl methacrylate was either present from the beginning in the monomers solution or slowly dropped after 6 h of reaction) in tetrahydrofuran (THF) at 40 °C over 48 h. Macromers with a methacrylate end groups fraction of ≈52% in a simple one-pot one-step procedure were obtained with molecular weights (Mn) of ≈7500–7900 g/mol. The obtained products under the one-pot one-step and two steps synthesis procedures carried out using 1 and 3 wt% of a CALB enzymatic catalyst were profusely characterized by NMR (1H and 13C), MALDI-TOF MS, and SEC. The methacrylate functional macromers obtained with the different procedures and 1 wt% of CALB were combined with an Irgacure® 369 initiator to undergo homopolymerization under UV irradiation for 10 and 30 min, in order to test their potential to obtain amorphous networks within minutes with similar properties to those typically obtained by complex acrylation/methacrylation procedures, which need multiple purification steps and harsh reagents such as acyl chlorides. To the best of our knowledge, this is the first time that it has been demonstrated that the obtention of methacrylate-functional predominantly linear macromers based on poly(glycerol adipate) is able to be UV crosslinked in a simple one-step procedure.

Easy and effective modification approaches for transition metal dichalcogenides are highly desired in order to make them active toward electrocatalysis. In this manner, we report functionalized molybdenum diselenide (MoSe2) and tungsten diselenide (WSe2) via metal-ligand coordination with pyridine rings for the subsequent covalent grafting of a cobalt-porphyrin. The new hybrid materials were tested towards an electrocatalytic hydrogen evolution reaction in both acidic and alkaline media and showed enhanced activity compared to intact MoSe2 and WSe2. Hybrids exhibited lower overpotential, easier reaction kinetics, higher conductivity, and excellent stability after 10,000 ongoing cycles in acidic and alkaline electrolytes compared to MoSe2 and WSe2. Markedly, MoSe2-based hybrid material showed the best performance and marked a significantly low onset potential of −0.17 V vs RHE for acidic hydrogen evolution reaction. All in all, the ease and fast modification route provides a versatile functionalization procedure, extendable to other transition metal dichalcogenides, and can open new pathways for the realization of functional nanomaterials suitable in electrocatalysis.

Plant viral nanoparticles (VNPs) have become an attractive platform for the development of novel nanotools in the last years because of their safety, inexpensive production, and straightforward functionalization. Turnip mosaic virus (TuMV) is one example of a plant-based VNP used as a nanobiotechnological platform either as virions or as virus-like particles (VLPs). Their functionalization mainly consists of coating their surface with the molecules of interest via chemical conjugation or genetic fusion. However, because of their limitations, these two methods sometimes result in non-viable constructs. In this paper, we applied the SpyTag/SpyCatcher technology as an alternative for the functionalization of TuMV VLPs with peptides and proteins. We chose as molecules of interest the green fluorescent protein (GFP) because of its good traceability, as well as the vasoactive intestinal peptide (VIP), given the previous unsuccessful attempts to functionalize TuMV VNPs by other methods. The successful conjugation of VLPs to GFP and VIP using SpyTag/SpyCatcher was confirmed through Western blot and electron microscopy. Moreover, the isopeptide bond between SpyTag and SpyCatcher occurred in vivo in co-agroinfiltrated Nicotiana benthamiana plants. These results demonstrated that SpyTag/SpyCatcher improves TuMV functionalization compared with previous approaches, thus implying the expansion of the application of the technology to elongated flexuous VNPs.

The 3D printing of titanium (Ti) offers countless possibilities for the development of personalized implants with suitable mechanical properties for different medical applications. However, the poor bioactivity of Ti is still a challenge that needs to be addressed to promote scaffold osseointegration. The aim of the present study was to functionalize Ti scaffolds with genetically modified elastin-like recombinamers (ELRs), synthetic polymeric proteins containing the elastin epitopes responsible for their mechanical properties and for promoting mesenchymal stem cell (MSC) recruitment, proliferation, and differentiation to ultimately increase scaffold osseointegration. To this end, ELRs containing specific cell-adhesive (RGD) and/or osteoinductive (SNA15) moieties were covalently attached to Ti scaffolds. Cell adhesion, proliferation, and colonization were enhanced on those scaffolds functionalized with RGD-ELR, while differentiation was promoted on those with SNA15-ELR. The combination of both RGD and SNA15 into the same ELR stimulated cell adhesion, proliferation, and differentiation, although at lower levels than those for every single moiety. These results suggest that biofunctionalization with SNA15-ELRs could modulate the cellular response to improve the osseointegration of Ti implants. Further investigation on the amount and distribution of RGD and SNA15 moieties in ELRs could improve cell adhesion, proliferation, and differentiation compared to the present study.

[EN] The modification of the surface properties of graphene with polymers provides a method for expanding its scope into new applications as a hybrid material. Unfortunately, the chemical inertness of graphene hinders the covalent functionalization required to build them up. Developing new strategies to enhance the graphene chemical activity for efficient and stable functionalization, while preserving its electronic properties, is a major challenge. We here devise a covalent functionalization method that is clean, reproducible, scalable, and technologically relevant for the synthesis of a large-scale, substrate-supported graphene–polymer hybrid material. In a first step, hydrogen-assisted plasma activation of p-aminophenol (p-AP) linker molecules produces their stable and covalent attachment to large-area graphene. Second, an in situ radical polymerization reaction of 2-hydroxyethyl acrylate (HEA) is carried out on the functionalized surface, leading to a graphene–polymer hybrid functional material. The functionalization with a hydrophilic and soft polymer modifies the hydrophobicity of graphene and might enhance its biocompatibility. We have characterized these hybrid materials by atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS) and Raman spectroscopy and studied their electrical response, confirming that the graphene/p-AP/PHEA architecture is anchored covalently by the sp3 hybridization and controlled polymerization reaction on graphene, retaining its suitable electronic properties. Among all the possibilities, we assess the proof of concept of this graphene-based hybrid platform as a humidity sensor. An enhanced sensitivity is obtained in comparison with pristine graphene and related materials. This functional nanoarchitecture and the two-step strategy open up future potential applications in sensors, biomaterials, or biotechnology fields.

In the paper, for the first time, the new concept of rechargeable cathode for Mg-based seawater cells is demonstrated. The pristine carbon felt (CF) is functionalized with electrodeposited polypyrrole (PPy), and the composite with silver chloride (AgCl) is prepared by the modified successive ion layer adsorption and reaction (SILAR) method. Pristine carbon felt – polypyrrole (CF/PPy) and carbon felt - polypyrrole - silver chloride (CF/PPy-AgCl) are investigated as potential rechargeable positive electrodes for the magnesium seawater cell. During charge, which can be accomplished with small photovoltaic cells, polypyrrole, and silver are oxidized while on Mg hydrogen is evolved. During discharge dissolution of Mg alloy, and reduction of doped polypyrrole and silver chloride occurred. The specific capacity, energy, and power of the cell, as well as cyclic stability, are estimated. The possible application of the cell is also proposed.

The 3D printing of titanium (Ti) offers countless possibilities for the development of personalized implants with suitable mechanical properties for different medical applications. However, the poor bioactivity of Ti is still a challenge that needs to be addressed to promote scaffold osseointegration. The aim of the present study was to functionalize Ti scaffolds with genetically modified elastin-like recombinamers (ELRs), synthetic polymeric proteins containing the elastin epitopes responsible for their mechanical properties and for promoting mesenchymal stem cell (MSC) recruitment, proliferation, and differentiation to ultimately increase scaffold osseointegration. To this end, ELRs containing specific cell-adhesive (RGD) and/or osteoinductive (SNA15) moieties were covalently attached to Ti scaffolds. Cell adhesion, proliferation, and colonization were enhanced on those scaffolds functionalized with RGD-ELR, while differentiation was promoted on those with SNA15-ELR. The combination of both RGD and SNA15 into the same ELR stimulated cell adhesion, proliferation, and differentiation, although at lower levels than those for every single moiety. These results suggest that biofunctionalization with SNA15-ELRs could modulate the cellular response to improve the osseointegration of Ti implants. Further investigation on the amount and distribution of RGD and SNA15 moieties in ELRs could improve cell adhesion, proliferation, and differentiation compared to the present study., Peer Reviewed, Postprint (published version)

Gold nanospecies produced by a historically inspired two-liquid phase system were immobilized on plate-like mesoporous silica, SBA-15, functionalized with mercaptopropyl groups by a post-synthesis method, and the resulting materials were tested in the oxidation of cyclohexene with molecular oxygen at atmospheric pressure. The main purpose of this approach was to compare the physicochemical properties and catalytic performance of these materials with those of previously reported related materials functionalized by in situ methods during synthesis. In addition, catalytic tests under ambient lighting and darkness and also in the presence and absence of the initiator tert-butyl hydroperoxide (TBHP) were carried out. The samples were characterized by chemical analysis, N2 adsorption/desorption, TGA, SEM, HRTEM, UV-vis spectroscopy and XPS. Gold nanoclusters and isolated gold atoms but no AuNPs were found in the catalysts (0.31–2.69 wt.% of gold). The XPS shows that nearly 60% of the -SH groups (1.33 wt.% of S) were oxidized to sulphonic groups upon gold immobilization. The AuNCs and isolated gold atoms evolved in the the reaction medium to form AuNPs. The activity of the samples was lower than that of the catalysts supported on related S-bearing SBA-15 functionalized in situ, which was attributed to their different Au/S ratios, which in turn regulated the evolutionary process of the gold species during the reaction. The catalysts turned out to be inactive in darkness, which evidences that the cyclohexene oxidation carried out at ambient illumination is actually photocatalyzed by the AuNPs formed in situ during the reaction. The TBHP initiator is required to obtain the activity in order to counteract the inhibitors of cyclohexene auto-oxidation present in the commercial reagent. On the other hand, no major differences in the selectivity among the different catalysts and reactions were observed, with 2-cyclohexen-1-one and 2-cyclohexen-1-ol resulting from the allylic oxida

Hypothesis: Citrate capped gold nanoparticles (AuNPs-citrate) are the starting material for most of the academic and industrial applications using gold nanoparticles. AuNPs-citrate must usually be functionalized with organic (bio)molecules, through a ligand exchange process, to become suitable for the envisaged application. The evaluation of the efficiency of the ligand-exchange process with a simple and convenient procedure is challenging. Experiments: Fluoride was used to evaluate the efficiency of a ligand exchange process from AuNPs-citrate with five standard types of ligands. The relationship between the aggregation level of the AuNPs exposed to fluoride and the amount of residual citrate ligands at the surface of the AuNPs was studied. The fluoride-induced aggregation process was characterized with various techniques such as TEM, UV-Vis, ATR-FTIR or MANTA and then used to quickly identify the optimal conditions for the functionalization of AuNPs-citrate with a new ligand, i.e. a PEGylated calixarene-tetradiazonium salt (X4-(PEG)4). Findings: It was observed that the fluoride-induced aggregation of AuNPs is proportional to the efficiency of the ligands exchange. We believe that these results could benefit to everyone engineering AuNPs for advanced applications, as the fluoride-aggregation of AuNPs can be used as a general and versatile quality test to verify the coating density of organic (bio)molecules on AuNPs., SCOPUS: ar.j, info:eu-repo/semantics/published

Zinc germanate doped with Mn2+ (Zn2GeO4:Mn2+) is known to be a persistent luminescence green phosphor with potential applications in biosensing and bioimaging. Such applications demand nanoparticulated phosphors with a uniform shape and size, good dispersibility in aqueous media, high chemical stability, and surface-functionalization. These characteristics could be major bottlenecks and hence limit their practical applications. This work describes a one-pot, microwave-assisted hydrothermal method to synthesize highly uniform Zn2GeO4:Mn2+ nanoparticles (NPs) using polyacrylic acid (PAA) as an additive. A thorough characterization of the NPs showed that the PAA molecules were essential to realizing uniform NPs as they were responsible for the ordered aggregation of their building blocks. In addition, PAA remained attached to the NPs surface, which conferred high colloidal stability to the NPs through electrostatic and steric interactions, and provided carboxylate groups that can act as anchor sites for the eventual conjugation of biomolecules to the surface. In addition, it was demonstrated that the as-synthesized NPs were chemically stable for, at least, 1 week in phosphate buffer saline (pH range = 6.0-7.4). The luminescence properties of Zn2GeO4 NPs doped with different contents of Mn2+ (0.25-3.00 mol %) were evaluated to find the optimum doping level for the highest photoluminescence (2.50% Mn) and the longest persistent luminescence (0.50% Mn). The NPs with the best persistent luminescence properties were photostable for at least 1 week. Finally, taking advantage of such properties and the presence of surface carboxylate groups, the Zn2GeO4:0.50%Mn2+ sample was successfully used to develop a persistent luminescence-based sandwich immunoassay for the autofluorescence-free detection of interleukin-6 in undiluted human serum and undiluted human plasma samples. This study demonstrates that our persistent Mn-doped Zn2GeO4 nanophosphors are ideal candidates for biosens

The interaction between the plant lipid transfer protein Pru p 3 and phytosphingosine was assessed using an atomic force microscope. Phytosphingosine was covalently immobilized on DeepTipTM probes and Pru p 3 on MicroDeckTM functionalized substrates. Single-molecular interaction events between both molecules were retrieved and classified and the distribution for each one of the identified types was calculated. A success rate of over 70% was found by comparing the number of specific Pru p 3-phytosphingosine interaction events with the total number of recorded curves. The analysis of the distribution established among the various types of curves was further pursued to distinguish between those curves that can mainly be used for assessing the recognition between phytosphingosine (sensor molecule) and Pru p 3 (target molecule) in the context of affinity atomic force microscopy, and those that entail details of the interaction and might be employed in the context of force spectroscopy. The successful application of these functionalized probes and substrates to the characterization of the low-intensity hydrophobic interaction characteristic of this system is a clear indication of the potential of exploiting this approach with an extremely wide range of different biological molecules of interest. The possibility of characterizing molecular assembly events with single-molecule resolution offers an advantageous procedure to plough into the field of molecular biomimetics.

Uniform sodium-dysprosium double molybdate (NaDy(MoO4)2) nanoparticles having different morphologies (spheres and ellipsoids) and tunable size have been synthesized for the first time in literature. The procedure is based on a homogeneous precipitation process at moderated temperatures (≤220 °C) from solutions containing appropriated precursors dissolved in ethylene glycol-water mixtures, in the absence (spheres) or the presence (ellipsoids) of tartrate anions. The effects of the morphological characteristics (size and shape) of the nanoparticles on the magnetic relaxivity at high field (9.4 T) have been evaluated finding that the latter magnitude was higher for the spheres than for the ellipsoids, indicating their better suitability as contrast agents for high-field magnetic resonance imaging. Such nanoparticles have been successfully coated with polymers bearing carboxylate functional groups through a layer-by-layer process, which improves the colloidal stability of the nanoparticles in physiological media. It has been also found that the coating layer had no significant effects on the nanoparticles relaxivity and that such coated nanoparticles exhibited a high biocompatibility and a high chemical stability. In summary, we have developed NaDy(MoO4)2 based bioprobes which meet the required criteria for their use as contrast agents for high-field magnetic resonance imaging.

[EN] Vernonia oil is a naturally epoxidized triglyceride oil extracted from the seed of Vernonia galamensis, a native plant in East Africa. After hydrolysis to vernolic acid (VA) and derivatization, vernolic acid methyl ester (VAME) is synthesized and used to functionalize ordered mesoporous materials (OMM). Al-MCM-41 with Si/Al ratio of 15, pure silica SBA-15 and periodic mesoporous organosilica (PMO) are employed as supports exploring the different surface properties. Following optimization of the VAME/OMM ratios, selected samples, i.e. those with 13% VAME, were impregnated with AgNO3 in NaBH4 to obtain Ag-nanoparticles. The final AgVAMEOMM potential catalysts were characterized by transmission electron microscopy, observing an efficient loading of Ag nanoparticles in pure silica SBA-15 with VAME with 500 m2 specific surface area and 6 nm pore size.

Graphene-based materials such as graphene oxide (GO) have demonstrated extraordinary sensitivity towards water molecules due to the hydrophilic nature. The hydrophilicity of GO can be further improved via additional functionalization. Previous studies suggest that the interaction between GO and water molecules results in the formation of a hydrogen bond network and modifies the interlayer structure of GO laminates. Based on the recent developments, we present our opinion on the interaction between moisture and graphene oxide and how this interaction can be utilized for environmental applications such as moisture detection and atmospheric water harvesting.

Pd-catalyzed asymmetric allylic substitution (AAS) is a highly effective method for producing chiral molecules with alkene-substituted frameworks which can be further derivatized. However, its stereochemical outcome is affected by the steric requirements of the substrate and only a narrow set of nucleophiles yield excellent enantioselectivities. In this regard, phosphite-oxazolines have emerged as strong candidates to be privileged ligands for this process, providing results that surpass most of the previously published studies. They have provided high enantiocontrol when used in the Pd-AAS of several hindered and unhindered substrates, using a wide range of C-, O-, and N-nucleophiles. In this concept, we review and discuss the current progress made in the design of tailor-made phosphite-oxazoline ligand libraries for the Pd-AAS of a broad range of substrates and nucleophiles and its application in the construction of chiral complex molecules.

The properties of carbon nanotubes (CNTs) can be effectively tailored by decorating their surface with metal nanoparticles. For the decoration, first plasma functionalization is used to add oxygen chemical groups to the CNTs surface. Afterwards, the Ox-CNTs are decorated with Ni-Pd bimetallic nanoparticles using plasma sputtering deposition, a clean, fast, and environmentally friendly functionalization method. The grafted oxygen groups serve as nucleation sites for the growth of the bimetallic nanoparticles. Finally, the Ni-Pd nanoparticle-decorated CNTs are assessed as a sensing layer for the detection of toluene.

[EN] Polymer capsules fabricated via the layer-by-layer (LbL) approach have attracted a great deal of attention for biomedical applications thanks to their tunable architecture. Compared to alternative methods, in which the precise control over the final properties of the systems is usually limited, the intrinsic versatility of the LbL approach allows the functionalization of all the constituents of the polymeric capsules following relatively simple protocols. In fact, the final properties of the capsules can be adjusted from the inner cavity to the outer layer through the polymeric shell, resulting in therapeutic, diagnostic, or theranostic (i.e., combination of therapeutic and diagnostic) agents that can be adapted to the particular characteristics of the patient and face the challenges encountered in complex pathologies. The biomedical industry demands novel biomaterials capable of targeting several mechanisms and/or cellular pathways simultaneously while being tracked by minimally invasive techniques, thus highlighting the need to shift from monofunctional to multifunctional polymer capsules. In the present review, those strategies that permit the advanced functionalization of polymer capsules are accordingly introduced. Each of the constituents of the capsule (i.e., cavity, multilayer membrane and outer layer) is thoroughly analyzed and a final overview of the combination of all the strategies toward the fabrication of multifunctional capsules is presented. Special emphasis is given to the potential biomedical applications of these multifunctional capsules, including particular examples of the performed in vitro and in vivo validation studies. Finally, the challenges in the fabrication process and the future perspective for their safe translation into the clinic are summarized.

[ES] La combinación de la plasmónica y la optomecánica molecular está demostrando ser un campo potencialmente prometedor para el desarrollo de sensores de THz integrados que permiten acoplar esta señal a la del espectro visible, proporcionando un nuevo abanico de oportunidades de diagnóstico prácticamente inocuo para el paciente. La espectroscopia Raman es un aspecto clave en este caso, ya que ofrece la posibilidad de detectar la señal resultante del acople de señales. Por ello, el desarrollo de nuevas metodologías experimentales es esencial para generar y caracterizar las estructuras nanofotónicas que compondrán estos detectores de THz. En este trabajo, se han utilizado dos tipos de moléculas para funcionalizar las superficies plasmónicas, las cuales permiten el acoplamiento de señales en estos rangos de frecuencia. Estas son el Biphenil-4-tiol (BPT) y el 5-amino-2- mercaptobenzimidazole (ABIZ), habiendo desarrollado para esta última nueva técnica de funcionalización de superficies. Para generar las estructuras plasmónicas, se han depositado nanopartículas (NPs) de oro en la superficie de estructuras litografiadas mediante dos metodologías, siendo una de ellas una nueva técnica de transferencia de NPs que se ha denominado \textit{micro-contact printing}. Estas estructuras han sido caracterizadas con éxito mediante distintas técnicas. También se ha ensamblado un nuevo setup experimental para realizar Espectroscopia Raman mejorada por guía de ondas (WERS), lo cual es importante para simular las condiciones de guiado de la onda, así como para caracterizar dichos circuitos. Por ultimo, se han realizado simulaciones para determinar posibles estructuras plasmónicas nuevas que permitan el acoplamiento de las señales., [CA] La combinacio de la plasm ´ onica i l’optomec ´ anica molecular est ´ a demostrant ser un camp potencial- ` ment prometedor per al desenrotllament de sensors de THz integrats que permeten acoblar este senyal a la de l’espectre visible, proporcionant un nou palmito d’oportunitats de diagnostic pr ` acticament ` innocu per al pacient. L’espectroscopia Raman ` es un aspecte clau en este cas, ja que oferix la pos- ´ sibilitat de detectar el senyal resultant de l’acoble de senyals. Per aixo, el desenrotllament de noves ` metodologies experimentals es essencial per a generar i caracteritzar les estructures nanofot ´ onicas que ´ compondran estos detectors de THz. En aquest treball, s’han utilitzat dos tipus de molecules per a fun- ` cionalizar les superf´ıcies plasmoniques, les quals permeten l’adaptament de senyals en estos rangs de ` frequ¨encia. Estes s ` on el Biphenil-4-tiol (BPT) i el 5-amino-2-mercaptobenzimidazole (ABIZ), havent ´ desenvolupat per a aquesta ultima una nova t ´ ecnica de funcionalitzaci ` o de superf ´ ´ıcies. Per a generar les estructures plasmoniques, s’han depositat nanopart ` ´ıculas (NPs) d’or en la superf´ıcie d’estructures litografiades per mitja de dos metodologies, sent una d’elles una nova t ` ecnica de transfer ` encia de ` NPs que s’ha denominat micro-contact printing. Estes estructures han sigut caracteritzades amb exit per mitj ` a de distintes t ` ecniques. Tamb ` e s’ha generat un nou setup experimental per a realitzar ´ Espectroscopia Raman millorada per guia d’ones (WERS), la qual cosa ` es important per a simular ´ les condicions de guiat de l’onda, aix´ı com per a caracteritzar els mencionats circuits. Per ultim, ´ s’han realitzat simulacions per a determinar possibles estructures plasmoniques noves que permeten ` l’adaptament de les senyals, [EN] Combining plasmonics and molecular optomechanics is proving to be a potentially promising approach for the development of integrated THz sensors which allow the coupling of this signal to the visible spectrum, providing a new range of diagnostic opportunities that are virtually innocuous for the patient. Raman spectroscopy is a key issue here, as it offers the possibility to detect the resulting signal coupling. Therefore, the development of new experimental methodologies is essential to generate and characterize the nanophotonic structures that will compose these THz detectors. In this work, two types of molecules have been used to functionalize the plasmonic surfaces, which allow the coupling of signals in these frequency ranges. These are Biphenyl-4-thiol (BPT) and 5-amino-2-mercaptobenzimidazole (ABIZ), having developed a new surface functionalization technique for the latter. In order to generate the plasmonic structures, gold nanoparticles (NPs) have been deposited on the surface of lithographed structures by two methodologies, one of them being a new NPs transfer technique called micro-contact printing. These structures have been successfully characterized using different techniques. A new experimental setup has also been assembled to perform Waveguide Enhanced Raman Spectroscopy (WERS), which is important to simulate the wave-guiding conditions, as well as to characterize such circuits. Finally, simulations have been performed to determine possible new photonic nanostructures for signal coupling.

This project takes advantage of molecular dynamic simulation for the design of polymer nanocomposites. The newly synthesized low-dimensional carbon nanomaterials show unlimited potential in enhancing the mechanical performance of the polymer. The atomistic simulation approach enables a comprehensive characterization approach for the materials down to atomic level and establish in-detail insights into their mechanical behaviors usually beyond the reach of experiments. The obtained results and analysis establish a fundamental understanding of the enhancement mechanisms for the nanoscale reinforcements in polymer nanocomposites, which could eventually guide their design, fabrication, and engineering implementation.

One of the biggest challenges in producing fuel cells at affordable prices is to synthesize carbon materials selectively doped with graphitic nitrogen, as it is considered the most active nitrogen species for the oxygen reduction reaction (ORR). So far, all strategies focus on the use of nitrogen-containing carbon precursors, which limits the functionalization of commercially available carbon materials. Here, we present a post-functionalization method to boost the catalytic properties of carbon materials for the ORR by selectively enriching activated carbons with nitrogen graphitic species. A commercial high-surface area activated carbon was post-functionalized by a two-step procedure. First, the commercial carbon was mixed with different carbon/urea weight ratios and heated in air at 350 °C. Then, the functionalized materials were heat-treated at high temperature (from 700 to 1300 °C) to tailor the amount and distribution of the different nitrogen species in the resulting carbon structure. Nitrogen functionalization using a carbon to urea weight ratio of 1:2 and heat-treatment at 1100 °C led to highly selective doping in graphitic nitrogen species, which provided the tools to individually asses the catalytic activity of these nitrogen species. In addition, this study presents a low-cost and easily feasible synthesis route to improve the catalytic activity of carbon materials, leading to an onset potential of almost 0.9 V compared to reversible hydrogen electrode for ORR in an alkaline electrolyte. Moreover, this study provides significant evidence for the key role of graphitic nitrogen.

Current biomaterial-based approaches for cartilage repair are unable to provide the mechanical characteristics required for healthy joint function. This thesis examines the development of mechanically robust hydrogel biomaterials formed by two interpenetrating polymer networks as a potential avenue for functional cartilage repair.

[ES] Funcionalización directa del polietileno con ésteres de diferentes longitudes y formas, adición de carbenos y posterior transesterificación, para el estudio de sus diferentes estabilidades hidrolíticas.

Visible light induced singlet nucleophilic carbenes undergo rapid [2 + 1]-cycloaddition with tethered olefins to afford unique bicyclo[3.1.0]hexane and bicyclo[4.1.0]heptane scaffolds.

Sustainable wood nanotechnologies that combine optical transmittance and mechanical performance are interesting for new functionalities utilizing transparency. Wood is a sophisticated bio-based material with a natural hierarchical, anisotropic and porous structure. The wood cellular structure can be functionalized at the micro and nanostructural level for the design of advanced functional materials. In recent years, the development of transparent wood biocomposites derived from delignified wood substrates have gained interest because they combine attractive structural properties with optical functionality. Nanostructural tailoring of transparent wood biocomposites is required to improve optical transmittance, mechanical performance, and to add new functionalities. In this thesis, environmentally friendly material components and green chemical processes have been developed for the fabrication of nanostructurally tailored transparent wood biocomposites. Mesoporous delignified wood substrates with preserved microstructure and cellulose microfibril alignment in the cell wall are used as reinforcement in transparent wood biocomposites. Chemical functionalization strategies using renewable maleic, itaconic and succinic anhydrides have been explored for molecular and nanostructural tailoring of delignified cell walls. Cyclic anhydride functionalization results in high degree of esterification, reduces moisture content in the wood substrate, improves monomer diffusion within the cell wall, and further enables interface tailoring at the molecular scale with possibility for covalent attachment with polymer matrix. Transparent wood biocomposites were prepared by methyl methacrylate monomer impregnation followed by in situ polymerization within the chemically modified wood substrates. The anhydride-functionalized transparent wood biocomposites have improved wood-polymer interfacial interactions, resulting in improved optical and mechanical properties. Moreover, a bio-based poly, Hållbara nanoteknologiska trämaterial som kombinerar optisk transparens med mekanisk prestanda är av intresse för nya applikationer där transparens nyttjas. Trä är ett sofistikerat biobaserat material med en naturligt hierarkisk struktur som är anisotrop och porös. Avancerade funktionella material kan framställas genom funktionalisering av träets cellstruktur på mikro- och nanonivå. Utvecklingen av transparenta träbiokompositer, som framställs från delignifierat trä, har under de senaste åren väckt intresse då materialen kombinerar attraktiva strukturella egenskaper med optiska funktioner. Strukturell kontroll på nanonivå är nödvändig för förbättrad optisk transmittans, mekanisk prestanda samt för att tillägga nya egenskaper. I denna avhandling har miljövänliga materialkomponenter och gröna kemiska processer använts för att strukturellt skräddarsy transparenta träkompositer på nanonivå. Mesoporösa och delignifierade träsubstrat med bevarad mikrostruktur och orientering av cellulosamikrofibriller i cellväggen används som förstärkning i transparenta träkompositer. Strategier för kemisk funktionalisering med förnybara malein-, itakon- och bärnstenssyraanhydrider har undersökts för att skräddarsy delignifierade cellväggar. Funktionalisering med cykliska anhydrider resulterar i hög förestringsgrad som minskar fukthalten i träsubstratet, förbättrar monomerdiffusion inom cellväggarna samt möjliggör ytterligare anpassning av gränsytor för kovalent bindning med polymermatris. Transparenta träkompositer framställdes först genom impregnering med metylmetakrylatmonomer följt av in situ polymerisation i de kemiskt modifierade träsubstraten. Transparenta träbiokompositer framställda från träsubstrat som funktionaliserats med anhydrider uppvisar förbättrade gränsytor mellan trä och polymer, vilket resulterar i förbättrade optiska och mekaniska egenskaper. En biobaserad polymermatris från förnybar limonenoxid och akrylsyra utvecklades sedan för att framställa helt biobaserade trans, QC 2022-01-18

Current state-of-the-art thermal technologies for CO2 capture and concentration (CCC) from industrial emissions and air are energetically inefficient. In contrast, electrochemical CCC (eCCC) using redox carriers can theoretically approach 100% efficiency. However, there are currently few oxygen-stable redox carriers suitable for eCCC. Quinone derivatives have previously been studied as redox carriers as they have no affinity for CO2 in the fully oxidized state and an enhanced affinity for CO2 in their reduced states. Unfortunately, the quinones used in prior studies displayed an unfavorable tradeoff between their second reduction potential (E1/2) and CO2 binding constant (KCO2). As a result, reduced quinones that exhibit a sufficient KCO2 for flue gas or atmospheric CO2 capture have E1/2 values negative of the O2/O2•- reduction potential. To improve our understanding of the structural and electronic relationships that correlate KCO2 and E1/2, we report the largest set of quinones that have been experimentally evaluated for their KCO2 and E1/2 properties. The trends in the E1/2 and KCO2 properties were further investigated through extensive quantum chemical calculations to inform experimental carrier design. Notably, we identified structural handles to manipulate E1/2 and KCO2 properties of quinones; however, the altered steric and electronic effects did not disrupt their linear dependence.

Diazonium reactions with carbon nanotubes form optical sp3 defects that can be used in optical and electrical circuits. We investigate a direct on-device reaction supported by confined laser irradiation and present a technique where an arbitrary carbon nanotube can be preferentially functionalized within a device by matching the light frequency with its transition energy. An exemplary reaction was carried out between (9,7) nanotube and 4-bromobenzenediazonium tetrafluoroborate. The substrate supported nanotubes of multiple semiconducting chiralities were locally exposed to laser light while monitoring the reaction kinetics in situ via Raman spectroscopy. The chiral selectivity of the reaction was confirmed by resonant Raman spectroscopy, reporting a 10 meV E22 transition energy red-shift only of the targeted species. We further demonstrated this method on a single tube (9,7) electroluminescent device and show a 25 meV red-shifted emission of the ground state E11 compared to the emission from the pristine tubes.

High-performance regenerated silkworm (Bombyx mori) silk fibers can be produced efficiently through the straining flow spinning (SFS) technique. In addition to an enhanced biocompat-ibility that results from the removal of contaminants during the processing of the material, regenerated silk fibers may be functionalized conveniently by using a range of different strategies. In this work, the possibility of implementing various functionalization techniques is explored, including the production of fluorescent fibers that may be tracked when implanted, the combination of the fibers with enzymes to yield fibers with catalytic properties, and the functionalization of the fibers with cell-adhesion motifs to modulate the adherence of different cell lineages to the material. When considered globally, all these techniques are a strong indication not only of the high versatility of-fered by the functionalization of regenerated fibers in terms of the different chemistries that can be employed, but also on the wide range of applications that can be covered with these functionalized fibers.