Biological Activity and Thrombogenic Properties of Oxide Nanotubes on the Ti-13Nb-13Zr Biomedical Alloy.

The success of implant treatment is dependent on the osseointegration of the implant. The main goal of this work was to improve the biofunctionality of the Ti-13Nb-13Zr implant alloy by the production of oxide nanotubes (ONTs) layers for better anchoring in the bone and use as an intelligent carrier in drug delivery systems. Anodization of the Ti-13Nb-13Zr alloy was carried out in 0.5% HF, 1 M (NH4)2SO4 + 2% NH4F, and 1 M ethylene glycol + 4 wt.% NH4F electrolytes. Physicochemical characteristics of ONTs were performed by high-resolution electron microscopy (HREM), X-ray photoelectron spectroscopy (XPS), and scanning Kelvin probe (SKP). Water contact angle studies were conducted using the sitting airdrop method. In vitro biological properties and release kinetics of ibuprofen were investigated. The results of TEM and XPS studies confirmed the formation of the single-walled ONTs of three generations on the bi-phase (α + ß) Ti-13Nb-13Zr alloy. The ONTs were composed of oxides of the alloying elements. The proposed surface modification method ensured good hemolytic properties, no cytotoxity for L-929 mouse cells, good adhesion, increased surface wettability, and improved athrombogenic properties of the Ti-13Nb-13Zr alloy. Nanotubular surfaces allowed ibuprofen to be released from the polymer matrix according to the Gallagher-Corrigan model.

Identification and Biological Evaluation of a Water-Soluble Fullerene Nanomaterial as BTK Kinase Inhibitor.

Introduction: Thanks to recent advances in synthetic methodology, water-soluble fullerene nanomaterials that interfere with biomolecules, especially DNA/RNA and selected proteins, have been found with tremendous potential for applications in nanomedicine. Herein, we describe the synthesis and evaluation of a water-soluble glycine-derived [60]fullerene hexakisadduct (HDGF) with T h symmetry, which is a first-in-class BTK protein inhibitor. Methods: We synthesized and characterized glycine derived [60]fullerene using NMR, ESI-MS, and ATR-FT-IR. DLS and zeta potential were measured and high-resolution transmission electron microscopy (HRTEM) observations were performed. The chemical composition of the water-soluble fullerene nanomaterial was examined by X-ray photoelectron spectrometry. To observe aggregate formation, the cryo-TEM analysis was carried out. The docking studies and molecular dynamic simulations were performed to determine interactions between HDGF and BTK. The in vitro cytotoxicity was evaluated on RAJI and K562 blood cancer cell lines. Subsequently, we examined the induction of cell death by autophagy and apoptosis by determining the expression levels of crucial genes and caspases. We investigated the direct association of HDGF on inhibition of the BTK signalling pathway by examining changes in the calcium levels in RAJI cells after treatment. The inhibitory potential of HDGF against non-receptor tyrosine kinases was evaluated. Finally, we assessed the effects of HDGF and ibrutinib on the expression of the BTK protein and downstream signal transduction in RAJI cells following anti-IgM stimulation. Results: Computational studies revealed that the inhibitory activity of the obtained [60]fullerene derivative is multifaceted: it hampers the BTK active site, interacting directly with the catalytic residues, rendering it inaccessible to phosphorylation, and binds to residues that form the ATP binding pocket. The anticancer activity of produced carbon nanomaterial revealed that it inhibited the BTK protein and its downstream pathways, including PLC and Akt proteins, at the cellular level. The mechanistic studies suggested the formation of autophagosomes (increased gene expression of LC3 and p62) and two caspases (caspase-3 and -9) were responsible for the activation and progression of apoptosis. Conclusion: These data illustrate the potential of fullerene-based BTK protein inhibitors as nanotherapeutics for blood cancer and provide helpful information to support the future development of fullerene nanomaterials as a novel class of enzyme inhibitors.

Production, Characterization and Application of Oxide Nanotubes on Ti-6Al-7Nb Alloy as a Potential Drug Carrier.

This work concerns the development of a method of functionalization of the surface of the biomedical Ti-6Al-7Nb alloy by producing oxide nanotubes (ONTs) with drug-eluting properties. Shaping of the morphology, microstructure, and thickness of the oxide layer was carried out by anodization in an aqueous solution of 1 M ethylene glycol with the addition of 0.2 M NH4F in the voltage range 5-100 V for 15-60 min at room temperature. The characterization of the physicochemical properties of the obtained ONTs was performed using SEM, XPS, and EDAX methods. ONTs have been shown to be composed mainly of TiO2, Al2O3, and Nb2O5. Single-walled ONTs with the largest specific surface area of 600 cm2 cm-2 can be obtained by anodization at 50 V for 60 min. The mechanism of ONT formation on the Ti-6Al-7Nb alloy was studied in detail. Gentamicin sulfate loaded into ONTs was studied using FTIR, TG, DTA, and DTG methods. Drug release kinetics was determined by UV-Vis spectrophotometry. The obtained ONTs can be proposed for use in modern implantology as carriers for drugs delivered locally in inflammatory conditions.

The Structure-Properties-Cytotoxicity Interplay: A Crucial Pathway to Determining Graphene Oxide Biocompatibility.

Interest in graphene oxide nature and potential applications (especially nanocarriers) has resulted in numerous studies, but the results do not lead to clear conclusions. In this paper, graphene oxide is obtained by multiple synthesis methods and generally characterized. The mechanism of GO interaction with the organism is hard to summarize due to its high chemical activity and variability during the synthesis process and in biological buffers' environments. When assessing the biocompatibility of GO, it is necessary to take into account many factors derived from nanoparticles (structure, morphology, chemical composition) and the organism (species, defense mechanisms, adaptation). This research aims to determine and compare the in vivo toxicity potential of GO samples from various manufacturers. Each GO sample is analyzed in two concentrations and applied with food. The physiological reactions of an easy model Acheta domesticus (cell viability, apoptosis, oxidative defense, DNA damage) during ten-day lasting exposure were observed. This study emphasizes the variability of the GO nature and complements the biocompatibility aspect, especially in the context of various GO-based experimental models. Changes in the cell biomarkers are discussed in light of detailed physicochemical analysis.

Towards water-soluble [60]fullerenes for the delivery of siRNA in a prostate cancer model.

This paper presents two water-soluble fullerene nanomaterials (HexakisaminoC60 and monoglucosamineC60, which is called here JK39) that were developed and synthesized as non-viral siRNA transfection nanosystems. The developed two-step Bingel-Hirsch reaction enables the chemical modification of the fullerene scaffold with the desired bioactive fragments such as D-glucosamine while keeping the crucial positive charged ethylenediamine based malonate. The ESI-MS and 13C-NMR analyses of JK39 confirmed its high Th symmetry, while X-ray photoelectron spectroscopy revealed the presence of nitrogen and oxygen-containing C-O or C-N bonds. The efficiency of both fullerenes as siRNA vehicles was tested in vitro using the prostate cancer cell line DU145 expressing the GFP protein. The HexakisaminoC60 fullerene was an efficient siRNA transfection agent, and decreased the GFP fluorescence signal significantly in the DU145 cells. Surprisingly, the glycofullerene JK39 was inactive in the transfection experiments, probably due to its high zeta potential and the formation of an extremely stable complex with siRNA.

Impact of Acidity Profile on Nascent Polyaniline in the Modified Rapid Mixing Process-Material Electrical Conductivity and Morphological Study.

Polyaniline (PANI) was synthesized chemically with the modified rapid mixing protocol in the presence of sulfuric acid of various concentrations. A two-step synthetic procedure was utilized maintaining low-temperature conditions. Application of the modified rapid mixing protocol allowed obtaining a material with local ordering. A higher concentration of acid allowed obtaining a higher yield of the reaction. Structural characterization performed with Fourier-transform infrared (FTIR) analysis showed the vibration bands characteristic of the formation of the emeraldine salt in both products. Ultraviolet-visible light (UV-Vis) spectroscopy was used for the polaronic band and the p-p* band determination. The absorption result served to estimate the average oxidation level of PANI by comparison of the ratio of the absorbance of the polaronic band to that of the π-π* transition. The absorbance ratio index was higher for PANI synthesized in a more acidic solution, which showed a higher doping level for this polymer. For final powder products, particle size distributions were also estimated, proving that PANI (5.0 M) is characterized by a larger number of small particles; however, these particles can more easily agglomerate and form larger structures. The X-ray diffraction (XRD) patterns revealed an equilibrium between the amorphous and semicrystalline phase in the doped PANI. A higher electrical conductivity value was measured for polymer synthesized in a higher acid concentration. The time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis showed that the molecular composition of the polymers was the same; hence, the difference in properties was a result of local ordering.

Physicochemical Analysis of Sediments Formed on the Surface of Hydrophilic Intraocular Lens after Descemet's Stripping Endothelial Keratoplasty.

An intraocular lens (IOL) is a synthetic, artificial lens placed inside the eye that replaces a natural lens that is surgically removed, usually as part of cataract surgery. The opacification of the artificial lens can be related to the formation of the sediments on its surface and could seriously impair vision. The physicochemical analysis was performed on an explanted hydrophilic IOL and compared to the unused one, considered as a reference IOL. The studies were carried out using surface sensitive techniques, which can contribute to a better understanding of the sedimentation process on hydrophilic IOLs' surfaces. The microscopic studies allowed us to determine the morphology of sediments observed on explanted IOL. The photoelectron spectroscopy measurements revealed the presence of organic and inorganic compounds at the lens surface. Mass spectroscopy measurements confirmed the chemical composition of deposits and allowed for chemical imaging of the IOL surface. Applied techniques allowed to obtain a new set of information approximating the origin of the sediments' formation on the surface of the hydrophilic IOLs after Descemet's stripping endothelial keratoplasty.

Europium Doping Impact on the Properties of MBE Grown Bi2Te3 Thin Film.

The impact of europium doping on the electronic and structural properties of the topological insulator Bi2Te3 is studied in this paper. The crystallographic structure studied by electron diffraction and transmission microscopy confirms that grown by Molecular Beam Epitaxy (MBE) system film with the Eu content of about 3% has a trigonal structure with relatively large monocrystalline grains. The X-ray photoemission spectroscopy indicates that europium in Bi2Te3 matrix remains divalent and substitutes bismuth in a Bi2Te3 matrix. An exceptional ratio of the photoemission 4d multiplet components in Eu doped film was observed. However, some spatial inhomogeneity at the nanometer scale is revealed. Firstly, local conductivity measurements indicate that the surface conductivity is inhomogeneous and is correlated with a topographic image revealing possible coexistence of conducting surface states with insulating regions. Secondly, Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) depth-profiling also shows partial chemical segregation. Such in-depth inhomogeneity has an impact on the lattice dynamics (phonon lifetime) evaluated by femtosecond spectroscopy. This unprecedented set of experimental investigations provides important insights for optimizing the process of growth of high-quality Eu-doped thin films of a Bi2Te3 topological insulator. Understanding such complex behaviors at the nanoscale level is a necessary step before considering topological insulator thin films as a component of innovative devices.

Nanolayers of Poly(N,N'-Dimethylaminoethyl Methacrylate) with a Star Topology and Their Antibacterial Activity.

In this paper, we focus on the synthesis and characterization of novel stable nanolayers made of star methacrylate polymers. The effect of nanolayer modification on its antibacterial properties was also studied. A covalent immobilization of star poly(N,N'-dimethylaminoethyl methacrylate) (PDMAEMA) to benzophenone functionalized glass or silicon supports was carried out via a "grafting to" approach using UV irradiation. To date, star polymer UV immobilization has never been used for this purpose. The thickness of the resulting nanolayers increased from 30 to 120 nm with the molar mass of the immobilized stars. The successful bonding of star PDMAEMA to the supports was confirmed by surface sensitive quantitative spectroscopic methods. Next, amino groups in the polymer layer were quaternized with bromoethane, and the influence of this modification on the antibacterial properties of the obtained materials was analyzed using a selected reference strain of bacteria. The resulting star nanolayer surfaces exhibited higher antimicrobial activity against Bacillus subtilis ATCC 6633 compared to that of the linear PDMAEMA analogues grafted onto a support. These promising results and the knowledge about the influence of the topology and modification of PDMAEMA layers on their properties may help in searching for new materials for antimicrobial applications in medicine.

A Study of Catalytic Oxidation of a Library of C2 to C4 Alcohols in the Presence of Nanogold.

The classical stoichiometric oxidation of alcohols is an important tool in contemporary organic chemistry. However, it still requires huge modifications in order to comply with the principles of green chemistry. The use of toxic chemicals, hazardous organic solvents, and the large amounts of toxic wastes that result from the reactions are a few examples of the problems that must be solved. Nanogold alone or conjugated with palladium were supported on different carriers (SiO2, C) and investigated in order to evaluate their catalytic potential for environmentally friendly alcohol oxidation under solvent-free and base-free conditions in the presence H2O2 as a clean oxidant. We tested different levels of Au loading (0.1⁻1.2% wt.) and different active catalytic site forms (monometallic Au or bimetallic Au⁻Pd sites). This provided new insights on how the structure of the Au-dispersions affected their catalytic performance. Importantly, the examination of the catalytic performance of the resulting catalysts was oriented toward a broad scope of alcohols, including those that are the most resistant to oxidation-the primary aliphatic alcohols. Surprisingly, the studies proved that Au/SiO2 at a level of Au loading as low as 0.1% wt. appeared to be efficient and prospective catalytic system for the green oxidation of alcohol. Most importantly, the results revealed that 0.1% Au/SiO2 might be the catalyst of choice with a wide scope of utility in the green oxidation of various structurally different alcohols as well as the non-activated aliphatic ones.

Reduced fecundity and cellular changes in Acheta domesticus after multigenerational exposure to graphene oxide nanoparticles in food.

Despite the fact that the demand for graphene and its derivatives in commercial applications is still growing, many aspects of its toxicity and biocompatibility are still poorly understood. Graphene oxide, which is released into the environment (air, soil and water) as so-called nanowaste or nanopollution, is able to penetrate living organisms. It is highly probable that, due to its specific nature, it can migrate along food chains thereby causing negative consequences. Our previous studies reported that short-term exposure to graphene oxide may increase the antioxidative defense parameters, level of DNA damage, which results in numerous degenerative changes in the gut and gonads. The presented research focuses on reproductive dysfunction and cellular changes in Acheta domesticus after exposure to GO nanoparticles in food (concentrations of 20 and 200 µg·g-1 of food) throughout their entire life cycle. The results showed that long-term exposure to GO caused a significant decrease in the reproductive capabilities of the animals. Moreover, the next generation of A. domesticus had a lower cell vitality compared to their parental generation. It is possible that graphene oxide can cause multigenerational harmful effects.

Stable star polymer nanolayers and their thermoresponsiveness as a tool for controlled culture and detachment of fibroblast sheets.

In this study, we describe novel thermoresponsive star copolymer surfaces used for the first time for the culture of fibroblast sheets, followed by their detachment, controlled by a change in temperature. To date, no star polymers, or their layers, have been used for this purpose. A "grafting to" strategy was applied to obtain poly[oligo(ethylene glycol) methacrylate] star layers on functionalized solid supports. Atom transfer radical polymerization of oligo(ethylene glycol) methacrylates and glycidyl methacrylate initiated with modified poly(arylene oxindole) yielded stars with molar masses up to Mn = 380 000 g mol-1. Stars were attached to a glass substrate via the reaction between the functional epoxy groups of the stars with the amine groups of the functionalized substrate. The thickness of the layer was related to the dimensions of isolated stars in solution, which showed that multilayers were obtained. Above the phase transition temperature, polymer nanolayers were hydrophobic, thus enabling the growth of fibroblasts on their surfaces and the formation of a cell sheet. Decreasing the temperature below the phase transition temperature made the star surfaces hydrophilic. This eliminated the affinity of the surface for cells and led to detachment of the intact fibroblast sheet. These observations have shown for the first time that the star polymer architecture favors the detachment of cell sheets as compared to linear polymer analogues grafted onto supports, thus reducing the time of this process. Knowledge of the influence of the polymer topology on layer properties and cell growth and detachment can aid in the development of polymeric materials for tissue culture applications.

Spectroscopic Studies on Organic Matter from Triassic Reptile Bones, Upper Silesia, Poland.

Fossil biomolecules from an endogenous source were previously identified in Cretaceous to Pleistocene fossilized bones, the evidence coming from molecular analyses. These findings, however, were called into question and an alternative hypothesis of the invasion of the bone by bacterial biofilm was proposed. Herewith we report a new finding of morphologically preserved blood-vessel-like structures enclosing organic molecules preserved in iron-oxide-mineralized vessel walls from the cortical region of nothosaurid and tanystropheid (aquatic and terrestrial diapsid reptiles) bones. These findings are from the Early/Middle Triassic boundary (Upper Roetian/Lowermost Muschelkalk) strata of Upper Silesia, Poland. Multiple spectroscopic analyses (FTIR, ToF-SIMS, and XPS) of the extracted "blood vessels" showed the presence of organic compounds, including fragments of various amino acids such as hydroxyproline and hydroxylysine as well as amides, that may suggest the presence of collagen protein residues. Because these amino acids are absent from most proteins other than collagen, we infer that the proteinaceous molecules may originate from endogenous collagen. The preservation of molecular signals of proteins within the "blood vessels" was most likely made possible through the process of early diagenetic iron oxide mineralization. This discovery provides the oldest evidence of in situ preservation of complex organic molecules in vertebrate remains in a marine environment.

Catalytic Gas-Phase Glycerol Processing over SiO2-, Cu-, Ni- and Fe- Supported Au Nanoparticles.

In this study, we investigated different metal pairings of Au nanoparticles (NPs) as potential catalysts for glycerol dehydration for the first time. All of the systems preferred the formation of hydroxyacetone (HYNE). Although the bimetallics that were tested, i.e., Au NPs supported on Ni, Fe and Cu appeared to be more active than the Au/SiO2 system, only Cu supported Au NPs gave high conversion (ca. 63%) and selectivity (ca. 70%) to HYNE.

Ni-Supported Pd Nanoparticles with Ca Promoter: A New Catalyst for Low-Temperature Ammonia Cracking.

In this paper we report a new nanometallic, self-activating catalyst, namely, Ni-supported Pd nanoparticles (PdNPs/Ni) for low temperature ammonia cracking, which was prepared using a novel approach involving the transfer of nanoparticles from the intermediate carrier, i.e. nano-spherical SiO2, to the target carrier technical grade Ni (t-Ni) or high purity Ni (p-Ni) grains. The method that was developed allows a uniform nanoparticle size distribution (4,4±0.8 nm) to be obtained. Unexpectedly, the t-Ni-supported Pd NPs, which seemed to have a surface Ca impurity, appeared to be more active than the Ca-free (p-Ni) system. A comparison of the novel PdNPs/Ni catalyst with these reported in the literature clearly indicates the much better hydrogen productivity of the new system, which seems to be a highly efficient, flexible and durable catalyst for gas-phase heterogeneous ammonia cracking in which the TOF reaches a value of 2615 mmolH2/gPd min (10,570 molNH3/molPd(NP) h) at 600°C under a flow of 12 dm3/h (t-Ni).

Conversion of Natural Tannin to Hydrothermal and Graphene-Like Carbons Studied by Wide-Angle X-ray Scattering.

The atomic structure of carbon materials prepared from natural tannin by two different techniques, high-temperature pyrolysis and low-temperature hydrothermal carbonization, was studied by wide-angle X-ray scattering. The obtained diffraction data were converted to the real space representation in the form of pair distribution functions. The X-ray photoelectron spectroscopy measurements provided information about the chemical state of carbon in tannin-based materials that was used to construct final structural models of the investigated samples. The results of the experimental data in both reciprocal and real spaces were compared with computer simulations based on the PM7 semiempirical quantum chemical method. Using the collected detailed information, structural models of the tannin-based carbons were proposed. The characteristics of the investigated materials at the atomic level were discussed in relation to their preparation method. The rearrangement of the tannin molecular structure and its transformation to graphene-like structure was described. The structure of tannin-based carbons pyrolyzed at 900 °C exhibited coherently scattering domains about 20 Å in size, consisting of two defected atomic layers and resembling a graphene-like arrangement.

Relevance of the poly(ethylene glycol) linkers in peptide surfaces for proteases assays.

Poly(ethylene glycol)s (PEGs) with different lengths were used as linkers during the preparation of peptide surfaces for protease detection. In the first approach, the PEG monolayers were prepared using a "grafting to" method on 3-aminopropyltrietoxysilane (APTES)-modified silicon wafers. Protected peptides with a fluorescent marker were synthesized by Fmoc solid phase synthesis. The protected peptide structures enabled their site-specific immobilization onto the PEG surfaces. Alternatively, the PEG-peptide surface was obtained by immobilizing a PEG-peptide conjugate directly onto the modified silicon wafer. The surfaces (composition, grafting density, hydrophilicity, and roughness) were characterized by time-of-flight-secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), contact angle (CA), and atomic force microscopy (AFM). Introducing the PEG linker between the peptide and surface increased their resistance toward nonspecific protein adsorption. The peptide surfaces were examined as analytical platforms to study the action of trypsin as a representative protease. The products of the enzymatic hydrolysis were analyzed by fluorescence spectroscopy, electrospray ionization-mass spectrometry (ESI-MS), and ToF-SIMS. Conclusions about the optimal length of the PEG linker for the analytical application of PEG-peptide surfaces were drawn. This work demonstrates an effective synthetic procedure to obtain PEG-peptide surfaces as attractive platforms for the development of peptide microarrays.