Search

This review presents a brief overview of recent insights into general reaction pathways in sol-gel synthesis of metal oxides. Metal-based sol-gel precursors display kinetically unhindered reactivity, combining high reaction speed with reversibility on a molecular level. The process producing metal oxide sols can thus be described as nucleation of an oxide phase with growth option efficiently precluded by extremely low solubility. The emerging nuclei are essentially Polyoxometalate (POM) species, with sizes in the colloid range starting from about 2 nm. They are stabilized in solution by colloid forces (charge interactions, hydrogen bonding, van der Waals forces), defined by the nature and arrangement of species on their surface, which permits them to be denoted as Micelles Templated by Self-Assembly of Ligands (MTSALs). The sol-gel transition occurs on aggregation of particles resulting in percolation. Exploiting this mechanism, it is possible to produce materials with controlled porosity, biocompatibility, and even to access thermodynamically challenging phases that cannot be produced by conventional synthetic techniques. Graphical Abstract

The ongoing world-wide Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) pandemic shows the need for new potential sensing and therapeutic means against the CoV viruses. The SARS-CoV-2 nsp1 protein is important, both for replication and pathogenesis, making it an attractive target for intervention. In this study we investigated the interaction of this protein with two types of titania nanoparticles by NMR and discovered that while lactate capped particles essentially did not interact with the protein chain, the aminoalcohol-capped ones showed strong complexation with a distinct part of an ordered α-helix fragment. The structure of the forming complex was elucidated based on NMR data and theoretical calculation. To the best of our knowledge, this is the first time that a tailored titanium oxide nanoparticle was shown to interact specifically with a unique site of the full-length SARS-CoV-2 nsp1 protein, possibly interfering with its functionality.

Linothele fallax (Mello-Leitao) (L. fallax) spider web, a potentially attractive tissue engineering material, was investigated using quantitative peak force measurement atomic force microscopy and scanning electron microscopy with energy dispersive spectroscopy both in its natural state and after treatment with solvents of different protein affinities, namely, water, ethanol, and dimethyl sulfoxide (DMSO). Native L. fallax silk threads are densely covered by globular objects, which constitute their inseparable parts. Depending on the solvent, treating L. fallax modifies its appearance. In the case of water and ethanol, the changes are minor. In contrast, DMSO practically removes the globules and fuses the threads into dense bands. Moreover, the solvent treatment influences the chemistry of the threads' surface, changing their adhesive and, therefore, biocompatibility and cell adhesion properties. On the other hand, the solvent-treated web materials' contact effect on different types of biological matter differs considerably. Protein-rich matter controls humidity better when wrapped in spider silk treated with more hydrophobic solvents. However, carbohydrate plant materials retain more moisture when wrapped in native spider silk. The extracts produced with the solvents were analyzed using nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry techniques, revealing unsaturated fatty acids as representative adsorbed species, which may explain the mild antibacterial effect of the spider silk. The extracted metabolites were similar for the different solvents, meaning that the globules were not "dissolved" but "fused into" the threads themselves, being supposedly rolled-in knots of the protein chain.

A molecular precursor approach to titania (anatase) nanopowders modified with different amounts of rare-earth elements (REEs: Eu, Sm, and Y) was developed using the interaction of REE nitrates with titanium alkoxides by a two-step solvothermal–combustion method. The nature of an emerging intermetallic intermediate was revealed unexpectedly for the applied conditions via a single-crystal study of the isolated bimetallic isopropoxide nitrate complex [Ti2Y(iPrO)9(NO3)2], a nonoxo-substituted compound. Powders of the final reaction products were characterized by powder X-ray diffraction, scanning electron microscopy–energy-dispersive spectroscopy, Fourier transform infrared, X-ray photoelectron spectroscopy, Raman spectroscopy, and photoluminescence (PL). The addition of REEs stabilized the anatase phase up to ca. 700 °C before phase transformation into rutile became evident. The photocatalytic activity of titania modified with Eu3+ and Sm3+ was compared with that of Degussa P25 titania as the control. PL studies indicated the incorporation of Eu and Sm cations into titania (anatase) at lower annealing temperatures (500 °C), but an exclusion to the surface occurred when the annealing temperature was increased to 700 °C. The efficiency of the modified titania was inferior to the control titania while illuminated within narrow wavelength intervals (445–465 and 510–530 nm), but when subjected to a wide range of visible radiation, the Eu3+- and Sm3+-modified titania outperformed the control, which was attributed both to doping of the band structure of TiO2 with additional energy levels and to the surface chemistry of the REE-modified titania., Molecular insight into the mechanism of solution−combustion synthesis provided clues to understanding the photocatalytic properties of rare-earth-doped nanotitania.

Low-cost mesoporous silicas of the SBA-15 family were prepared, aimed for removal of a broad spectrum of both cationic and anionic forms of hazardous metal pollutants (Cr(III, VI), Mn(II, VII), Pb(II), Cd(II), and Cu(II)) from environmental water. Series of mono- and bifunctional materials with immobilized ethylenediaminetriacetic acid (EDTA), primary amine (NH

In the pursuit of understanding the factors guiding interactions between polyoxometalates (POMs) and biomolecules, several complexes between Keggin phosphomolybdate and diglycine have been produced at different acidity and salinity conditions, leading to difference in stoichiometry and in crystal structure. Principal factors determining how the POM and dipeptide interact appear to be pH, ionic strength of the medium, and the molar ratio of POM to peptide. An important effect turned out to be even the structure-directing role of the sodium cations coordinating carbonyl functions of the peptide bond. Given the interest in applying POMs in biological systems, these factors are highly relevant to consider. In the view of recent interest in using POMs as nano catalysts in peptide hydrolysis also the potential Keggin POM transformation in phosphate buffered saline medium was investigated leading to insight that nanoparticles of zirconium phosphate (ZrP) can be actual catalysts for breakdown of the peptide bond.

Transition-metal oxide nanostructured materials are potentially attractive alternatives as anodes for Li ion batteries and as photocatalysts. Combining the structural and thermal stability of titanium oxides with the relatively high oxidation potential and charge capacity of molybdenum(VI) oxides was the motivation for a search for approaches to mixed oxides of these two metals. Challenges in traditional synthetic methods for such materials made development of a soft chemistry single-source precursor pathway our priority. A series of bimetallic Ti-Mo alkoxides were produced by reactions of homometallic species in a 1:1 ratio. Thermal solution reduction with subsequent reoxidation by dry air offered in minor yields Ti2Mo2O4(OMe)6(OiPr)6 (1) by the interaction of Ti(OiPr)4 with MoO(OMe)4 and Ti6Mo6O22(OiPr)16(iPrOH)2 (2) by the reaction of Ti(OiPr)4 with MoO(OiPr)4. An attempt to improve the yield of 2 by microhydrolysis, using the addition of stoichiometric amounts of water, resulted in the formation with high yield of a different complex, Mo7Ti7+xO31+x(OiPr)8+2x (3). Controlled thermal decomposition of 1–3 in air resulted in their transformation into the phase TiMoO5 (4) with an orthorhombic structure in space group Pnma, as determined by a Rietveld refinement. The electrochemical characteristics of 4 and its chemical transformation on Li insertion were investigated, showing its potential as a promising anode material for Li ion batteries for the first time. A lower charge capacity and lower stability were observed for its application as an anode for a Na ion battery., Controlled decomposition of a structurally characterized Ti-Mo oxo-alkoxide precursor offered an approach to the new ternary oxide TiMoO5, showing promising characteristics as an anode material for Li ion batteries.

Template-free synthesis of MnFe2O4 nanopowder is carried out by co-precipitation in a basic medium, evaluating the effects of cation ratio and reaction temperature on the phase composition crystallinity of the resulting powder. Single-phase samples of the target spinel are obtained at the stoichiometric Mn : Fe = 1 : 2 ratio under reflux conditions (100 °C), as confirmed by X-ray diffraction (XRD) and Fourier Transformed Infrared (FTIR) spectroscopy. Transmission electron microscopy (TEM) images confirmed that nanostructured MnFe2O4 particles are obtained, which is further supported by Debye–Scherrer calculations from XRD data and by AFM measurements. The produced oxide demonstrated considerable thermal stability according to TGA data. Magnetic characteristics are strongly dependent on the content of magnetic phase and phase composition, achieving a maximum of 54 emu g−1 for single-phase stoichiometric MnFe2O4. Further, the electrochemical stability of this material as the anode is investigated in Li-ion batteries (LIBs). When the MnFe2O4 electrode is operated in the potential window of 0.01–3.0 V, the reversible capacity is enhanced by almost 45% (802 mA h g−1) after the 100th cycle with reference to the 2nd cycle reversible capacity (548 mA h g−1). Methodically dQ/dV plots are analyzed and compared to understand processes behind the evolution of extra capacity beyond its theoretical limit. Further, the upper cut-off potential is tuned to identify a stable operating potential window for the MnFe2O4 anode in LIBs.

A novel nanoceria-nanocellulose hybrid material has been developed and evaluated as a potential drug delivery system. Crystalline nanoceria was synthesized in situ in the nanocellulose to obtain a homogenous distribution without extensive particle aggregation. The hybrid materials were loaded with two antibiotic drugs, triclosan and ampicillin, and one anti-inflammatory drug, diclofenac. The bacteriostatic effect on the gram-negative bacteria Escherichia coli was evaluated for the hybrid materials containing triclosan and ampicillin. The nanoceria-nanocellulose hybrid displayed a better retention of ampicillin than triclosan in the disc diffusion test, which is likely due to the presence of the carboxylic acid group in ampicillin that has better affinity for ceria compared to the phenolic group in triclosan. However, drug release studies in solution revealed rapid release of ampicillin and diclofenac, indicative of outer-sphere complexes between ceria and the drugs.

One-step sol-gel synthesis for covering magnetic particles with polysiloxane layers with equivalent to Si(CH2)3NHC(S) NHC2H5 groups has been proposed. Unique properties of this functional group, containing sulfur and nitrogen, and the developed approach open wide (and novel) opportunities for the controlled surface design. A number of factors affecting the characteristics of such materials and their sorption properties towards heavy metal ions were analyzed. Results of scanning and transmission electron microscopy studies, Fourier-transform infrared spec-troscopy, nitrogen adsorption-desorption measurements, elemental analysis, thermogravimetric analysis, and X-ray powder diffraction analysis indicated that, depending on the ratio of core/shell components, the resulting spherical moieties with size of 35.1-43.1 nm, can form agglomerates of larger sizes. Packing of these aggregates offers porosity to such materials, having a dense or loose polysiloxane shell, with thiourea groups load of 0.67-1.05 mmol/g. The synthesized materials proved to be effective in extraction of Cu(II), Pb(II), Cd(II), Hg(II), Ag(I), Au(III), Zn(II) ions from aqueous solutions, as well as in selectively adsorption of Au(III) ions at pH = 3 and Cu(II) ions at pH = 5.5. X-ray photoelectron spectroscopy demonstrated different types of interactions between metal ions and the thiourea groups, depending on pH.

The ongoing world-wide Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) pandemic shows the need for new sensing and therapeutic means against the CoV viruses. The SARS-CoV-2 nsp1 protein is important, both for replication and pathogenesis, making it an attractive target for intervention. In recent years nanoparticles have been shown to interact with peptides, ranging in size from single amino acids up to proteins. These nanoparticles can be tailor-made with specific functions and properties including bioavailability. To the best of our knowledge, in this study we show for the first time that a tailored titanium oxide nanoparticle interacts specifically with a unique site of the full-length SARS-CoV-2 nsp1 protein. This can be developed potentially into a tool for selective control of viral protein functions.

Mesoporous alumina and γ-Al2O3–NaAlO2 composites with different morphology were produced by soft chemistry methods using polyethylenimine (PEI), pluronic P123 (P123), and polymer–colloid complex (PCC) derived from them as templates in solution. Sodium aluminate was applied as an additive for production of the mesoporous γ-Al2O3–NaAlO2 composite. The obtained samples were characterized by scanning and transmission electron microscopy, atomic force microscopy, Fourier transform IR spectrometry, X-ray diffraction analysis, and low-temperature N2 adsorption–desorption analysis. The effect of sodium aluminate introduction on the morphological features of the obtained samples was investigated. Mesostructured aluminum oxide obtained using individual templates such as P123 and PEI possesses cylindrical pores, whereas applying PCC resulted in the formation slit-shaped pores. The produced mesoporous aluminum oxide and γ-Al2O3–NaAlO2 composite had a narrow pore size distribution and large surface area. This approach was demonstrated to allow for the control of pore sizes and shapes.

Water and humidity severely affect the material properties of spider major ampullate silk, causing the fiber to become plasticized, contract, swell and undergo torsion. Several amino acid residue types have been proposed to be involved in this process, but the complex composition of the native fiber complicates detailed investigations. Here, we observe supercontraction in biomimetically produced artificial spider silk fibers composed of defined proteins. We found experimental evidence that proline is not the sole residue responsible for supercontraction and that tyrosine residues in the amorphous regions of the silk fiber play an important role. Furthermore, we show that the response of artificial silk fibers to humidity can be tuned, which is important for the development of materials for applications in wet environments, eg producing water resistant fibers with maximal strain at break and toughness modulus. Exposing spider silk to wet conditions can cause supercontraction. Here, tyrosine amino acid residues within the amorphous regions are found to contribute to supercontraction, which can be controlled by protein engineering.

In order to develop a new type of improved wound dressing, we combined the wound healing properties of nanotitania with the advantageous dressing properties of nanocellulose to create three different hybrid materials. The hemocompatibility of the synthesized hybrid materials was evaluated in an in vitro human whole blood model. To our knowledge, this is the first study of the molecular interaction between hybrid nanotitania and blood proteins. Two of the hybrid materials prepared with 3 nm colloidal titania and 10 nm hydrothermally synthesized titania induced strong coagulation and platelet activation but negligible complement activation. Hence, they have great potential as a new dressing for promoting wound healing. Unlike the other two, the third hybrid material using molecular ammonium oxo-lactato titanate as a titania source inhibited platelet consumption, TAT generation, and complement activation, apparently via lowered pH at the surface interface. It is therefore suitable for applications where a passivating surface is desired, such as drug delivery systems and extracorporeal circuits. This opens the possibility for a tailored blood response through the surface functionalization of titania.

A series of hybrid adsorbents were produced by surface modification with amino polycarboxylate ligands of industrially available microparticles (MP) of Kromasil® mesoporous nanostructured silica beads, bearing grafted amino propyl ligands. Produced materials, bearing covalently bonded functions as EDTA and TTHA, original Kromasil®, bearing amino propyl ligands, and bare particles, obtained by thermal treatment of Kromasil® in air, were characterized by SEM-EDS, AFM, FTIR, TGA and gas sorption techniques. Adsorption kinetics and capacity of surface-modified particles to adsorb Rare Earth Elements (REE), crucial for extraction in recycling processes, were evaluated under dynamic conditions, revealing specificity matching the ligand nature and the size of REE cations. A detailed comparison with earlier reported adsorbents for REE extraction was presented. The cytotoxicity was assessed using four different types of healthy cells, human skeletal muscles derived cells (SKMDC), fibroblast cells, macrophage cells (RAW264.7), and human umbilical vein endothelial cells (HUVECs), indicating lower toxicity of ligand-free MP than MP bearing amino poly-carboxylate functions. Internalization of the MP inside the cells and release of nitric oxide were observed. In addition, zebrafish embryos were exposed to high concentrations of MP and did not show any pronounced toxicity.

Chelating and ion-exchange N-functionalized mesoporous silicas (SBA-15) as selective adsorbents for removal of heavy metals were synthesized using template method. Fourier transform infrared spectroscopy, TEM analysis, N2 adsorption/desorption isotherms and titration analysis confirmed successful functionalisation of the tri-sodium salt of N-(triethoxysilylpropyl)ethylenediaminetriacetic acid (EDTA), protonated primary amine (NH3+Cl-) and its combinations onto the mesoporous silica (SBA-EDTA/NH2). The obtained materials featured beneficial properties of mesoporous silica SBA-15 with its high surface area and were successfully fictionalized with N-containing groups. The synthesized series of silicas were investigated for removal of Cr(III), Mn(III), Pb(II), Cd(II) and Cu(II) from model water solutions. The adsorption of target ions increased with the increase pH and its concentration in solution. The adsorption equilibrium data were well fitted to Langmuir isotherm model and maximum monolayer adsorption capacities for cations Pb(II), Cd(II), Cr(III) and Mn(II) were 185.6 mg g-1, 111.2 mg g-1, 57.7 mg g-1 and 49.4 mg g-1, respectively. The chelating interaction was considered as the main adsorption mechanism for metal ions (Cr(III), Mn(II), Pb(II), Cd(II), and Cu(II)). The adsorption capacities of SBA-EDTA and SBA-EDTA/NH2 samples toward studied metal ions were consistent with the Lewis ‘hard and soft acids and bases’ theory. The metal removal efficiency of adsorbents was near 96-92 % during three regeneration cycles. All these results indicated that the produced N-functionalized silica were promising for applications in environmental and analytical separation fields.

Protein nanofibrils (PNFs) have been prepared by whey protein fibrillation at low pH and in the presence of different metal ions. The effect of the metal ions was systematically studied both in terms of PNF suspension gelation behavior and fibrillation kinetics. A high valence state and a small ionic radius (e.g., Sn4+) of the metal ion resulted in the formation of hydrogels already at a metal ion concentration of 30 mM, whereas an intermediate valence state and larger ionic radius (Co2+, Ni2+, Al3+) resulted in the hydrogel formation occurring at 60 mM. A concentration of 120 mM of Na+ was needed to form a PNF hydrogel, while lower concentrations showed liquid behaviors similar to the reference PNF solution where no metal ions had been introduced. The hydrogel mechanics were investigated at steady-state conditions after 24 h of incubation/gelation, revealing that more acidic (smaller and more charged) metal ions induced ca. 2 orders of magnitude higher storage modulus as compared to the less acidic metal ions (with smaller charge and larger radius) for the same concentration of metal ions. The viscoelastic nature of the hydrogels was attributed to the ability of the metal ions to coordinate water molecules in the vicinity of the PNFs. The presence of metal ions in the solutions during the growth of the PNFs typically resulted in curved fibrils, whereas an upper limit of the concentration existed when oxides/hydroxides were formed, and the hydrogels lost their gel properties due to phase separation. Thioflavin T (ThT) fluorescence was used to determine the rate of the fibrillation to form 50% of the total PNFs (t(1/2)), which decreased from 2.3 to ca. 0.5 h depending on the specific metal ions added.

Only a few M–N bonded divalent group 14 precursors are available for vapor deposition, in particular for Ge and Pb. A majority of the reported precursors are dicoordinated with the Sn(II) amidinates, the only tetracoordinated examples. No Ge(II) and Pb(II) amidinates suitable for vapor deposition have been demonstrated. Herein, we present tetracoordinated Ge(II), Sn(II), and Pb(II) complexes bearing two sets of chelating 1,3-di-tert-butyltriazenide ligands. These compounds are thermally stable, sublime quantitatively between 60 and 75 °C (at 0.5 mbar), and show ideal single-step volatilization by thermogravimetric analysis., Only a few tetracoordinated M−N bonded vapor deposition precursors exist for divalent group 14 elements. Although there are a couple of volatile tetracoordinated tin(II) amidinates, no such Ge and Pb compounds are suitable. Herein, we present volatile group 14 triazenides as potential vapor deposition precursors. These compounds are thermally stable, sublime quantitatively between 65 and 70 °C (0.5 mbar), and show single-step volatilization curves by thermogravimetric analysis.

Amidinate and guanidinate ligands have been used extensively to produce volatile and thermally stable precursors for atomic layer deposition. The triazenide ligand is relatively unexplored as an alternative ligand system. Herein, we present six new Al(III) complexes bearing three sets of a 1,3-dialkyltriazenide ligand. These complexes volatilize quantitatively in a single step with onset volatilization temperatures of ∼150 °C and 1 Torr vapor pressures of ∼134 °C. Differential scanning calorimetry revealed that these Al(III) complexes exhibited exothermic events that overlapped with the temperatures of their mass loss events in thermogravimetric analysis. Using quantum chemical density functional theory computations, we found a decomposition pathway that transforms the relatively large hexacoordinated Al(III) precursor into a smaller dicoordinated complex. The pathway relies on previously unexplored interligand proton migrations. These new Al(III) triazenides provide a series of alternative precursors with unique thermal properties that could be highly advantageous for vapor deposition processes of Al containing materials., Six aluminum(III) 1,3-dialkyltriazenides were synthesized and their thermal properties explored. The compounds were purified by recrystallization and could be easily sublimed. Thermogravimetric analysis of compounds showed that all, except one, gave a single step evaporation with onset volatilization temperatures of ∼150 °C. DFT calculations revealed a unique decomposition pathway that leads to a small and more reactive Al species that would be highly advantageous for the surface reactions of atomic layer deposition.

Titania (anatase) nanoparticles were anisotropically functionalized in water-toluene Pickering emulsions to self-assemble into nanoshells with diameters from 500 nm to 3 μm as candidates for encapsulation of drugs and other compounds. The water-phase contained a hydrophilic ligand, glucose-6-phosphate, while the toluene-phase contained a hydrophobic ligand, n-dodecylphosphonic acid. The addition of a dilute sodium alginate suspension that provided electrostatic charge was essential for the self-limited assembly of the nanoshells. The self-assembled spheres were characterized by scanning electron microscopy, elemental mapping, and atomic force microscopy. Drug release studies using tetracycline suggest a rapid release dominated by surface desorption.

High-performance functional biomaterials are becoming increasingly requested. Numerous natural and artificial polymers have already demonstrated their ability to serve as a basis for bio-composites. Spider silk offers a unique combination of desirable aspects such as biocompatibility, extraordinary mechanical properties, and tunable biodegradability, which are superior to those of most natural and engineered materials. Modifying spider silk with various inorganic nanomaterials with specific properties has led to the development of the hybrid materials with improved functionality. The purpose of using these inorganic nanomaterials is primarily due to their chemical nature, enhanced by large surface areas and quantum size phenomena. Functional properties of nanoparticles can be implemented to macro-scale components to produce silk-based hybrid materials, while spider silk fibers can serve as a matrix to combine the benefits of the functional components. Therefore, it is not surprising that hybrid materials based on spider silk and inorganic nanomaterials are considered extremely promising for potentially attractive applications in various fields, from optics and photonics to tissue regeneration. This review summarizes and discusses evidence of the use of various kinds of inorganic compounds in spider silk modification intended for a multitude of applications. It also provides an insight into approaches for obtaining hybrid silk-based materials via 3D printing.

Indium nitride (InN) is characterized by its high electron mobility, making it a ground-breaking material for high frequency electronics. The difficulty of depositing high-quality crystalline InN currently impedes its broad implementation in electronic devices. Herein, we report a new highly volatile In(III) triazenide precursor and demonstrate its ability to deposit high-quality epitaxial hexagonal InN by atomic layer deposition (ALD). The new In(III) precursor, the first example of a homoleptic triazenide used in a vapor deposition process, was easily synthesized and purified by sublimation. Thermogravimetric analysis showed single step volatilization with an onset temperature of 145 degrees C and negligible residual mass. Strikingly, two temperature intervals with self-limiting growth were observed when depositing InN films. In the high-temperature interval, the precursor underwent a gas-phase thermal decomposition inside the ALD reaction chamber to produce a more reactive In(III) compound while retaining self-limiting growth behavior. Density functional theory calculations revealed a unique two-step decomposition process, which liberates three molecules of each propene and N-2 to give a smaller tricoordinated In(III) species. Stoichiometric InN films with very low levels of impurities were grown epitaxially on 4H-SiC. The InN films deposited at 325 degrees C had a sheet resistivity of 920 Omega/sq. This new triazenide precursor enables ALD of InN for semiconductor applications and provides a new family of M-N bonded precursors for future deposition processes. Funding Agencies|Swedish foundation for Strategic Research through the project "Time-resolved low temperature CVD for III-nitrides" [SSF-RMA 15-0018]; Knut and Alice Wallenberg foundation through the project "Bridging the THz gap" [KAW 2013.0049]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO Mat LiU) [2009 00971]

Two new precursors, produced by modification of zirconium t-butoxide with 1-dimethylamino-propanol-2 (HDMAP), solid Zr2(DMAP)3(OtBu)5 (1), and liquid Zr2(DMAP)4(OtBu)4 (2), were obtained by reaction of 1.5 and 2 equivalents of HDMAP, respectively, in toluene on Zr(OtBu)4. The produced compounds were characterized by Fourier-transform infrared spectroscopy, 1H and 13C nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA) to estimate their stability and volatility. Action of traces of water in solvents or contact with humid air transforms 1 and 2 into less soluble crystalline Zr2(DMAP)3(OtBu)4(OH) (3). Molecular structures of compounds 1 and 3 were established using single-crystal X-ray studies and for 2, they were elucidated by applying 2D 1H–13C-correlated NMR spectra. The crystals of 1 were subjected to hydrolysis via either storage in ambient atmosphere or immersion into boiling water and the resulting products were characterized by X-ray powder diffraction, TGA, scanning electron microscopy, and atomic force microscopy techniques. The product of hydrolysis in air, ZrO2-1, is essentially nonporous, while hydrolysis in boiling water results in ZrO2-2 with hierarchical macro-, meso-, and microporosity. Both materials are essentially X-ray amorphous with diffraction patterns appearing as oblique curves, resembling unresolved profiles of the monoclinic baddeleyite structure of ZrO2. Heat treatment at 200 and 400 °C does not affect essentially the morphology or porosity and leaves the phase composition unchanged, while that at 600 °C converts both samples into a tetragonal ZrO2 phase. The ZrO2-2 material is via this treatment losing microporosity and becoming macro–mesoporous with a well-defined pore size of about 3 nm. Heat treatment at 900 °C results in collapse of pores and transformation into a well-defined monoclinic baddeleyite structure for both materials.

Titanium (oxo-) alkoxide phosphonate complexes were synthesized using different titanium precursors and

For simultaneous water purification from both inorganic and organic pollutants, a novel multifunctional hybrid nanoadsorbent has been produced. Core–shell magnetic submicro-particles with iron oxid...

Iron-oxide nanoparticles (NPs) generated by environmental events are likely to represent health problems. alpha-Fe2O3 NPs were synthesized, characterized and tested in a model for toxicity utilizing human whole blood without added anticoagulant. MALDI-TOF of the corona was performed and activation markers for plasma cascade systems (complement, contact and coagulation systems), platelet consumption and release of growth factors, MPO, and chemokine/cytokines from blood cells were analyzed. The coronas formed on the pristine alpha-Fe2O3 NPs contained contact system proteins and they induced massive activation of the contact (kinin/kallikrein) system, as well as thrombin generation, platelet activation, and release of two pro-angiogeneic growth factors: platelet-derived growth factor and vascular endothelial growth factor, whereas complement activation was unaffected. The alpha-Fe2O3 NPs exhibited a noticeable toxicity, with kinin/kallikrein activation, which may be associated with hypotension and long-term angiogenesis in vivo, with implications for cancer, arteriosclerosis and pulmonary disease. Joint and equal contribution to senior authorship by Kristina N. Ekdahl, Padideh Davoodpour and Bo Nilsson

In our effort to develop new synthetic strategies for isolation of new phosphonate frameworks, we exploited the possibility to simultaneously utilize benzene-1,3,5-triphosphonic acid (H6btp) and di-2-pyridyl ketone (py2CO) which is a major player in the field of polynuclear metal complexes. This ligand blend in the Cu(II) chemistry afforded a two-dimensional framework comprising tetranuclear, [CuII4], secondary building units. The thorough investigation of the CuII / di-2-pyridyl ketone / benzene-1,3,5-triphosphonic acid reaction system also afforded a hydrogen bonded framework. The structure of the latter comprises the cationic [Cu{py2C(OH)2}2]2+ complex [py2C(OH)2 is the hydrate of py2CO], the dianion of benzene-1,3,5-triphosphonic acid (H4btp2-) and water solvates. The magnetic properties of the layered material were rationalized on the basis of magnetically isolated [CuII4] units dominated by antiferromagnetic interactions.

Phosphotungstic acid (POM) was crystallized together with the neurotransmitter γ-aminobutyric acid (GABA) in acidic medium to form [(HGABA)3PW12O40], compound 1. The latter would only crystalize in the presence of dopamine, while dopamine itself did not become a part of the complex, but crystallized separately as [(Hdopamine)2HPW12O40], compound 2, as previously reported. GABA interacts with POM via hydrogen bonding between the protonated amino group and a terminal oxygen on POM and also via protonated carboxylic acid group. Based on structural information from the crystal structures of 1 and 2 together with complementary studies using other catechols we attempted to provide molecular insight into the well-known structure-directing effect of dopamine. Strong hydrogen bonding between dopamine and POM, together with formation of “dopamine dimers” in the packed structure by interactions between the aromatic rings and intermolecular hydrogen bonding might be important factors for them in directing the self-assembly of polyoxometalates into complex hierarchal structures. Interaction between dopamine and GABA in solution was investigated by diffusion ordered spectrometry (DOSY) NMR in MilliQ-water and in 0.1 M HCl.

Organic dyes are common constituents in wastewater and contribute to accumulation of persistent organic pollutants in the environment. Common dyes are aromatic compounds, bearing a variety of hydrophilic functional groups. Their interaction with solid surfaces can thus involve both van-der-Waals and hydrophobic interactions and electrostatic and/or hydrogen bonding. Aiming to tailor adsorbents with specific capacity for removal of dyes, silica microspheres were synthesized, combining aminopropyl functions as moderators of hydrophilic interaction and bridging aliphatic and aromatic functions as potential moderators of hydrophobic and π-stacking interactions. Two groups of samples were produced: non-porous silica spheres with amino or combined amino and hydrophobic residues; and porous polysilsesquioxane spheres incorporating aminopropyl components and organic bridges in the silica network. The hydrophilicity/hydrophobicity of the samples was studied by the absorption of water and benzene vapors. Bridged fragments, expected to promote the porosity of the samples, as well as hydrophobicity, did not contribute to the latter, because polysilsesquioxanes were bearing large numbers of residual silanol groups. Particles synthesized using tetraethoxysilane were up to 130 nm in size and held 1.6–1.8 mmol/g of amino groups, while, materials prepared from bridged silanes featured particle agglomerates up to 300 nm, 2.2–2.7 mmol/g amino groups content, and specific surface area of 540–620 m2/g. Interaction with Cu2+ was used to probe concentration and surface location of the amino functions, reaching 76–203 mg/g. Adsorption of anionic (acid red 88), neutral (fluorescein) and cationic (methylene blue) dyes was investigated revealing multiple interactions between the sorbent and sorbate. The dye sorption capacity values were 81–262 mg/g for acid red 88, 26–132 mg/g for fluorescein, and 55–146 mg/g for methylene blue. Produced silica microspheres have potential as high performance sorbents for the extraction of copper(II) ions and the dyes, and can act as fluorescent carriers after the dye adsorption.

We present the structure of a new tetranuclear titanium oxo complex containing the antibacterial agent triclosan. This provides a good model for the interaction between triclosan and titania, which may be used for drug-delivery applications. The antibacterial activity of the hydrolyzed complex against Staphylococcus aureus is investigated. Thereafter, we use the obtained titanium oxo complex to demonstrate its susceptibility towards hydrolysis, contrary to the widespread belief that titanium oxo complexes are water-stable, and demonstrate that it transforms into titania (anatase) on contact with water. Both hydrolysis and thermolysis of the complex yield titania particles, of very uniform size and shape, that connect into 3D nanostructures; this is of interest for practical applications.

Lymphocytes, such as T cells and natural killer (NK) cells, have therapeutic promises in adoptive cell transfer (ACT) therapy, where the cells are activated and expanded in vitro, and then infused into a patient. However, the in vitro preservation of labile lymphocytes during transfer, manipulation, and storage has been one of the bottlenecks in the development and commercialization of therapeutic lymphocytes. Herein, we suggest a "cell-in-shell" (a.k.a. artificial spore) strategy to enhance the cell viability in the practical settings, while maintaining biological activities for therapeutic efficacy. A durable titanium oxide (TiO2) shell is formed on individual Jurkat T cells, and the CD3 and other antigens on cell surfaces remain accessible to the antibodies. Interleukin-2 (IL-2) secretion is also not hampered by the shell formation. This work suggests a chemical toolbox for effectively preserving lymphocytes in vitro and developing the lymphocyte-based cancer immunotherapy.

The reactions of Al(III), Ga(III) and In(III) nitrates with 2-quinaldic acid (qaH) afforded [Al2(OH)2(qa)4]·2H2O (1), [Ga(qa)2(H2O)2]NO3 (2) and [In(qa)2(NO3)(H2O)] (3), respectively, in high yields. The crystal structures of 1, 2 and 3 have been determined by single-crystal X-ray crystallography. The structure of 1 features a di-hydroxo bridged [Al2(μ-OH)2]4+ dimer in which each Al(III) is further ligated by two bidentate chelate qa− ligands. Complexes 2 and 3 are mononuclear with the M(III) ions in octahedral environments surrounded by two bidentate chelate qa− and two H2O in 2 or one H2O and a terminal NO3− in 3. Characteristic IR as well as thermal analysis and solid-state fluorescence are discussed.

Employment of di-2-pyridyl ketone and poly-carboxylates in CuII chemistry afforded four complex hydrogen-bonded frameworks, one one-dimensional (1D), one 2D and three 3D coordination polymers. Di-2-pyridyl ketone underwent several metal-assisted transformations to yield three CuII structural units which, in combination with the poly-carboxylate anions of the trimesic, isophthalic, 5-hydroxy-isophthalic and pyromellitic acids, provided access to extended frameworks by dative or hydrogen bonds. All nine complex frameworks were realized in terms of their topological analysis. The 3D and the 2D polymers consisted of [Cu2] dimers and were found to be dominated by ferromagnetic interactions. The origin of the ferromagnetic coupling was attributed to the counter complementarity of the simultaneous alkoxo/syn,syn-carboxylate bridges within the dimers.

Spider silk is a natural material possessing unique properties such as biocompatibility, regenerative and antimicrobial activity, and biodegradability. It is broadly considered an attractive matrix for tissue regeneration applications. Optical monitoring and potential control over tissue regrowth are attractive tools for monitoring of this process. In this work, we show upconversion modification of natural spider silk fibers with inorganic nanoparticles. To achieve upconversion, metal oxide nanoparticles were doped with low concentrations of rare-earth elements, producing potentially biocompatible luminescent nanomaterials. The suggested approach to spider silk modification is efficient and easy to perform, opening up sensing and imaging possibilities of biomaterials in a noninvasive and real-time manner in bio-integration approaches.