muramidase and titanium-dioxide

Protein adsorption plays a key role in bone repair and regeneration by affecting cell behavior. In this study, TiO

Topics: Adsorption; Animals; Biomarkers; Cell Proliferation; Cell Shape; Cells, Cultured; Gene Expression Regulation; Mesenchymal Stem Cells; Muramidase; Nanofibers; Osteogenesis; Particle Size; Protein Conformation; Rabbits; Serum Albumin, Bovine; Titanium; Water; X-Ray Diffraction

Nature has evolved several molecular machineries to promote the formation at physiological conditions of inorganic materials, which would otherwise be formed in extreme conditions. The molecular determinants of this process have been established over the last decade, identifying a strong role of electrostatics in the first steps of the precipitation. However, no conclusive, structure-based evidence has been provided so far. In this manuscript, we test the binding of lysozyme with silica and titania potential precursors. In contrast with the absence of structural information about the interaction with the silica precursor, we observe the interaction with a mononuclear titanium(IV) species, which is found to occur in a region rich of positive charges.

Topics: Inorganic Chemicals; Muramidase; Oxides; Static Electricity; Titanium

Lysozyme is an enzyme often used as an antibacterial agent in food industries and biochemical and pharmaceutical laboratories. Immobilisation of lysozyme by encapsulating in a nanotube has received much interest as it can enhance stability of the enzyme in ambient condition. Experimentally, various types of nanotubes have been proposed as a host for lysozyme. Here, we mathematically model the immobilisation process and the interaction between lysozyme and various types of nanotubes in order to compare the effectiveness of different nanotube materials. In this paper, we consider boron nitride, carbon, silicon, silicon carbide and titania nanotubes. For each type of nanotubes, we determine the critical radius that will maximise the interaction between the lysozyme molecule and the nanotube. Our results suggest that titania nanotube stands out as the most promising candidate for lysozyme storage and delivery. The model presented here can be extended to further investigate the interaction between different types of nanotube materials and protein structures for the development of effective molecular storage.

Topics: Enzymes, Immobilized; Models, Molecular; Muramidase; Nanotubes; Protein Conformation; Thermodynamics; Titanium

Streptavidin is a 58 kDa tetrameric protein with the highest known affinity to biotin with a wide range of applications in bionanotechnology and molecular biology. Dissolved streptavidin is stable at a broad range of temperature, pH, proteolytic enzymes and exhibits low non-specific binding. In this study, a streptavidin monolayer was assembled directly on a biotinylated TiO

Topics: Adsorption; Bacillus subtilis; Bacteria; Bacterial Adhesion; Biotinylation; Coated Materials, Biocompatible; Colony Count, Microbial; Escherichia coli; Hydrophobic and Hydrophilic Interactions; Implants, Experimental; Muramidase; Proteins; Proteolysis; Serum Albumin, Bovine; Streptavidin; Streptococcus; Surface Properties; Titanium

We present an in situ X-ray reflectivity study of the adsorption behavior of the protein lysozyme on titanium oxide layers under variation of different thermodynamic parameters, such as temperature, hydrostatic pressure, and pH value. Moreover, by varying the layer thickness of the titanium oxide layer on a silicon wafer, changes in the adsorption behavior of lysozyme were studied. In total, we determined less adsorption on titanium oxide compared with silicon dioxide, while increasing the titanium oxide layer thickness causes stronger adsorption. Furthermore, the variation of temperature from 20 to 80 °C yields an increase in the amount of adsorbed lysozyme at the interface. Additional measurements with variation of the pH value of the system in a region between pH 2 and 12 show that the surface charge of both protein and titanium oxide has a crucial role in the adsorption process. Further pressure-dependent experiments between 50 and 5000 bar show a reduction of the amount of adsorbed lysozyme with increasing pressure.

Topics: Adsorption; Hydrogen-Ion Concentration; Muramidase; Surface Properties; Temperature; Thermodynamics; Titanium; Water

Binding of lysozyme with AgTiO2 nanoparticles was analyzed by using absorption, fluorescence, time resolved and synchronous fluorescence measurements. In the presence of AgTiO2 nanoparticles, the fluorescence intensity of lysozyme was decreased. Static type of binding was confirmed through lifetime and ground state absorption measurements. From the fluorescence quenching data, the binding constant and the number of binding sites were found to be 1.5×10(4)M(-1) and 1.03, respectively. From the synchronous fluorescence spectroscopic measurements, tryptophan residue in lysozyme was found to have interaction with the nanoparticles. Further, the influence of AgTiO2 nanoparticles on the binding strength of lysozyme with a drug molecule was analyzed through fluorescence quenching methods. The presence of nanoparticles decreases the binding capability of drug with protein. Overall, the observed results will provide basic insights on the utilization of nanoparticles in drug delivery applications.

Topics: Binding Sites; Drug Carriers; Erythrosine; Fluorescent Dyes; Models, Molecular; Muramidase; Nanoparticles; Protein Binding; Silver Compounds; Spectrometry, Fluorescence; Titanium

A sensitive aptasensor based on a nanocomposite of hollow titanium dioxide nanoball, three-dimensional reduced graphene oxide, and polypyrrole (TiO2/3D-rGO/PPy) was developed for lysozyme detection. A lysozyme aptamer was easily immobilized onto the TiO2/3D-rGO/PPy nanocomposite matrix by assembling the aptamer onto graphene through simple π-stacking interactions and electrostatic interactions between PPy molecular chains and aptamer strands. In the presence of lysozyme, the aptamer on the adsorbent layer catches the target on the electrode interface, which generates a barrier for electrons and inhibits electron transfer, subsequently resulting in decreased electrochemically differential pulse voltammetric signals of a gold electrode modified with TiO2/3D-rGO/PPy. Using this strategy, a low limit of detection of 0.085 ng mL(-1) (5.5 pM) for detecting lysozyme was observed within the detection range of 0.1-50 ng mL(-1) (0.007-3.5 nM). The aptasensor also presents high specificity for lysozyme, which is unaffected by the coexistence of other proteins. Such an aptasensor opens a rapid, selective, and sensitive route to lysozyme detection. This finding indicates that the TiO2/3D-rGO/PPy nanocomposite could be used as an electrochemical biosensor for detecting proteins in the biomedical field.

Topics: Aptamers, Nucleotide; Biosensing Techniques; Electrochemistry; Electrodes; Graphite; Limit of Detection; Muramidase; Nanocomposites; Oxidation-Reduction; Polymers; Pyrroles; Surface Properties; Temperature; Titanium

A composite made of polyacrylic acid and hollow TiO2 spheres (TiO2@PPAA) was prepared by the plasma polymerization method and subsequently used as an electrode material for detecting lysozyme. The chemical structure, surface morphology, and electrochemical performance of the TiO2@PPAA composite were mainly affected by the plasma input power used during plasma polymerization. After optimizing plasma conditions, aptamer strands exhibited high adsorption affinity toward the surface of TiO2@PPAA composite via synergistic effects between TiO2 and PPAA. Electrochemical impedance spectroscopy results showed that the developed TiO2@PPAA aptasensor presents highly sensitive detection ability toward lysozyme; the limit of detection of the proposed aptasensor is 0.015 ng mL(-1) (1.04 pM) within the range of 0.05-100 ng mL(-1) in terms of 3σ value. The film further showed excellent selectivity toward lysozyme in the presence of interfering proteins, such as thrombin, bovine serum albumin, and immunoglobulin E. Thus, this aptasensing strategy might broaden the applications of plasma polymerized nanomaterials in the field of biomedical research and early clinical diagnosis.

Topics: Acrylic Resins; Aptamers, Nucleotide; Biosensing Techniques; Conductometry; Equipment Design; Equipment Failure Analysis; Feasibility Studies; Muramidase; Nanopores; Nanospheres; Plasma Gases; Porosity; Reproducibility of Results; Sensitivity and Specificity; Titanium

Poloxamer 188 (BASF Pluronic® F68) is widely used as a shear-protective excipient to enhance cell yield in agitated cultures and reduce cell adhesion in stationary cultures. However, little is known in any quantitative sense of its effect on protein adsorption and aggregation. Optical waveguide lightmode spectroscopy was used here to compare the adsorption kinetics exhibited by poloxamer 188, and polysorbates 80 and 20, in the presence and absence of a model protein (chicken egg white lysozyme) and in separate experiments, a recombinant protein (human granulocyte colony-stimulating factor) at hydrophilic, silica-titania surfaces. Experiments were performed in sequential and competitive adsorption modes, enabling the adsorption kinetic patterns to be interpreted in a fashion revealing the dominant mode of surfactant-mediated stabilization of protein in each case. Kinetic results showed that polysorbates 80 and 20 are able to inhibit protein adsorption only by their preferential location at an interface to which they show sufficient affinity, and not by formation of less surface active, protein-surfactant complexes. On the other hand, poloxamer 188 is able to inhibit protein adsorption by entering into formation of protein-surfactant complexes of low adsorption affinity (i.e., high colloidal stability), and not by its preferential location at the interface.

Topics: Adsorption; Animals; Chickens; Granulocyte Colony-Stimulating Factor; Humans; Muramidase; Poloxamer; Polysorbates; Protein Stability; Recombinant Proteins; Silicon Dioxide; Surface Properties; Surface-Active Agents; Titanium

Titanium-tungsten oxide composites with greatly enhanced photocatalytic activity were synthesized by lysozyme-mediated biomineralization. It was shown for the first time that simple control of the onset of biomineralization could enable fine tuning of the composition and crystallinity of the composites to determine their photocatalytic performance.

Topics: Catalysis; Cellulose; Muramidase; Nanoparticles; Oxides; Photochemical Processes; Rhodamines; Sunlight; Titanium; Tungsten

A general strategy was demonstrated here to immobilize proteins with various isoelectric points (IPs) in layered titanates. The immobilization of proteins with relative low IPs, such as bovine serum albumin (BSA) and lipase, in layered titanates was successfully by a novel polyelectrolyte-assisted electrostatic self-assembly technique, which is impossible by a conventional electrostatic self-assembly method. Lysozyme with relative high IP was detractively interacted with negative titanate nanosheets to form a bioinorganic composite. The native structures of proteins were retained after immobilizing although a significant difference in microstructures was observed among these composites. The amounts of immobilized proteins were up to ~68.3 wt.% for lysozyme, 37.2 wt.% for BSA and 21.5 wt.% for lipase. These composites were stable in the neutral and weakly acidic condition, and only releases <10% proteins in the pH<4 solution. The immobilized lysozyme and lipase exhibit excellent thermal stability, which retain their initial activities of about 70% at 70 °C for about 40 min. In addition, these composites are reusable, and the residual activities of immobilized enzymes are 68% for lysozyme and 61% for lipase after 10 recycles.

Topics: Biotechnology; Cations; Enzyme Stability; Enzymes, Immobilized; Hydrogen-Ion Concentration; Lipase; Muramidase; Temperature; Titanium

Non-fouling TiO2 surfaces are attractive for a wide range of applications such as biosensors and medical devices, where biologically inert surfaces are needed. Typically, this is achieved by controlled surface modifications which prevent protein adsorption. For example, polyethylene glycol (PEG) or PEG-derived polymers have been widely applied to render TiO2 surfaces biologically inert. These surfaces have been further modified in order to achieve specific bio-activation. Therefore, there have been efforts to specifically functionalize TiO2 surfaces with polymers with embedded biotin motives, which can be used to couple streptavidin for further functionalization. As an alternative, here a streptavidin layer was immobilized by self-assembly directly on a biotinylated TiO2 surface, thus forming an anti-adhesive matrix, which can be selectively bio-activated. The anti-adhesive properties of these substrates were analyzed by studying the interaction of the surface coating with fibronectin, lysozym, and osteoblast cells using surface plasmon resonance spectroscopy, atomic force microscopy, and light microscopy. In contrast to non-modified TiO2 surfaces, streptavidin-coated TiO2 surfaces led to a very biologically inert substrate, making this type of surface coating a promising alternative to polymer coatings of TiO2 surfaces.

Topics: Adsorption; Biotinylation; Cell Adhesion; Cell Line; Fibronectins; Humans; Kinetics; Microscopy, Atomic Force; Muramidase; Osteoblasts; Silanes; Streptavidin; Surface Properties; Titanium

The microscopic dynamics of hydration water exhibits some universal features that do not depend on the nature of the hydrated surface. We show that the hydration level dependence of the dynamic transition in the mean squared atomic displacements measured by means of elastic neutron scattering is qualitatively similar for hydration water in inorganic and organic hosts. The difference is that the former are 'rigid', whereas the dynamics of the latter can be enhanced by the motions of the hydration water. The overall hydration level appears to be the main parameter governing the magnitude of the mean squared atomic displacements in the hydration water, irrespective of the details of the hydrated host.

Topics: Animals; Elasticity; Muramidase; Organic Chemicals; RNA, Fungal; RNA, Transfer; Surface Properties; Temperature; Titanium; Water

The potential toxicity of engineered nanoparticles (NPs) for humans and the environment represents an emerging issue. Since the aquatic environment represents the ultimate sink for NP deposition, the development of suitable assays is needed to evaluate the potential impact of NPs on aquatic biota. The immune system is a sensitive target for NPs, and conservation of innate immunity represents an useful basis for studying common biological responses to NPs. Suspension-feeding invertebrates, such as bivalves, are particularly at risk to NP exposure, since they have extremely developed systems for uptake of nano and microscale particles integral to intracellular digestion and cellular immunity. Evaluation of the effects of NPs on functional parameters of bivalve immunocytes, the hemocytes, may help understanding the major toxic mechanisms and modes of actions that could be relevant for different NP types in aquatic organisms.In this work, a battery of assays was applied to the hemocytes of the marine bivalve Mytilus galloprovincialis to compare the in vitro effects of different n-oxides (n-TiO(2), n-SiO(2), n-ZnO, n-CeO(2)) chosen on the basis of their commercial and environmental relevance. Physico-chemical characterization of both primary particles and NP suspensions in artificial sea water-ASW was performed. Hemocyte lysosomal and mitochondrial parameters, oxyradical and nitric oxide production, phagocytic activity, as well as NP uptake, were evaluated. The results show that different n-oxides rapidly elicited differential responses hemocytes in relation to their chemical properties, concentration, behavior in sea water, and interactions with subcellular compartments. These represent the most extensive data so far available on the effects of NPs in the cells of aquatic organisms. The results indicate that Mytilus hemocytes can be utilized as a suitable model for screening the potential effects of NPs in the cells of aquatic invertebrates, and may provide a basis for future experimental work for designing environmentally safer nanomaterials.

Topics: Animals; Apoptosis Regulatory Proteins; Cerium; Hemocytes; Immunologic Factors; Lysosomes; Metal Nanoparticles; Microscopy, Electron, Transmission; Muramidase; Mytilus; Nitric Oxide; Phagocytosis; Ribosomal Proteins; RNA-Binding Proteins; Seawater; Silicon Dioxide; Titanium; Water Pollutants, Chemical; Zinc Oxide

The in situ formation of sub-100 nm solid frameworks stabilized against dissolution by the addition of nanoseeds allows the facile and controllable synthesis of TiO(2) (anatase) mesocrystalline structures with spherical shape, mesoporosity and sizes between 50 and 70 nm. As an example of their multifunctionality, these structures show good capabilities for enzyme immobilization and adequate photocatalytic properties.

Topics: Adsorption; Catalysis; Enzymes, Immobilized; Methylene Blue; Muramidase; Nanostructures; Particle Size; Photochemistry; Porosity; Surface Properties; Titanium; Ultraviolet Rays; X-Ray Diffraction

The fundamental experiments on the adsorption behaviors of proteins onto photocatalytic Ti(4+)-doped calcium hydroxyapatite (TiHap) particles were examined comparing to those onto the calcium hydroxyapatite (CaHap) and commercially available typical titanium oxide (TiO(2)) photocatalyst (TKP-101). The heat treated TiHap and CaHap particles were also used after treated these particles at 650°C for 1h (abbreviated as TiHap650 and CaHap650, respectively). All the adsorption isotherms of bovine serum albumin (BSA), myoglobin (MGB) and lysozyme (LSZ) from 1×10(-4)mol/dm(3) KCl solution were the Langmuirian type. The saturated amounts of adsorbed BSA (n(s)(BSA)) for the CaHap650 particles was higher than that for CaHap. Similar results were observed for TiHap and TiHap650. The adsorption of LSZ exhibited the same result of BSA, while the saturated amounts of adsorbed LSZ (n(s)(LSZ)) value on the TiHap were much higher than CaHap. However, the saturated amounts of adsorbed MGB (n(s)(MGB)) are almost equal to those for the CaHap and TiHap nevertheless whether these particles were heat treated at 650°C or not. The TKP-101 exhibited extremely small adsorption capacity of all proteins due to its small particle size of ca. 4nm in diameter. The independence of the n(s)(MGB) value on the zeta potential (zp) of the particles was explained by the electrostatical neutrality of MGB molecules. On the other hand, the n(s)(LSZ) values were increased with increase in the negative zp of the particles. This fact was explained by increasing the electrostatic attractive forces between negatively charged particles and positively charged LSZ. However, the n(s)(BSA) values exhibit maxima for the heat treated TiHap650 and CaHap650 particles. This result was interpreted to the formation of β-TCP crystal phase by the heat treatment. The produced Ca(2+) ions by dissolution from β-TCP phase may exert as binders between BSA and surfaces of the heat treated particles.

Topics: Adsorption; Animals; Binding Sites; Cattle; Chemistry, Pharmaceutical; Drug Compounding; Durapatite; Hot Temperature; Kinetics; Muramidase; Myoglobin; Particle Size; Photochemical Processes; Protein Binding; Serum Albumin, Bovine; Static Electricity; Titanium

Lysosomal enzymes isolated from egg white were directly immobilized on titanium (IV) oxide (TiO(2)) particles using shaking methods (150 rpm, room temperature, 10 min), and the immobilization efficiency, activity, and stability of lysosomal enzymes immobilized on TiO(2) were evaluated. Of the various mass ratios (w/w) of lysosomal enzymes to TiO(2) tested, we found that 100% immobilization efficiency was observed at a ratio of 1:20 (enzymes:TiO(2); w/w). Furthermore, the antimicrobial activities of the immobilized lysosomal enzymes were confirmed using viable cell counts against Escherichia coli. Our results showed that the antimicrobial activity of immobilized lysosomal enzymes is stable and can be maintained up to one month, but the antimicrobial activity of free enzymes without immobilization completely disappeared after five days in storage. In addition, enhanced immobilization efficiency was shown in TiO(2) pretreated with a divalent, positively charged ion, Ca(2+), and the antimicrobial activity for E. coli increased as a function of increasing ratio of immobilized enzymes. However, K(+), a monovalent, positively charged ion, did not have any positive effect on immobilization or antimicrobial activity. Finally, we suggest that activity and stability of immobilized lysosomal enzymes can be maintained for a longer time than those properties of free lysosomal enzymes.

Topics: Animals; Anti-Infective Agents; Calcium; Chickens; Drug Evaluation, Preclinical; Egg Proteins; Enzyme Stability; Enzymes, Immobilized; Escherichia coli; Female; Hydrolases; Lysosomes; Microscopy, Electron, Scanning; Muramidase; Particle Size; Potassium; Powders; Titanium

Nanomaterials have been used increasingly in industrial production and daily life, but their human exposure may cause health risks. The interactions of nanomaterial with functional biomolecules are often applied as a precondition for its cytotoxicity and organ toxicity where various proteins have been investigated in the past years. In the present study, nano-TiO(2) was selected as the representative of nanomaterials and lysozyme as a representative for enzymes. By investigating their interaction by various instrumentations, the objective is to identify the action sites and types, estimate the effect on the enzyme structure and activity, and reveal the toxicity mechanism of nanomaterial.. Laboratory-scale experiments were carried out to investigate the interactions of nano-TiO(2) with lysozyme. The interaction of nano-TiO(2) particles with lysozyme has been studied in the analogous physiological media in detail by UV spectrometry, fluorophotometry, circular dichroism (CD), scanning electron microscope, zeta-potential, and laser particle size.. The interaction accorded with the Langmuir isothermal adsorption and the saturation number of lysozyme is determined to be 580 per nano-TiO(2) particle (60 nm of size) with 4.7 x 10(6) M(-1) of the stability constant in the physiological media. The acidity and ion strength of the media obviously affected the binding of lysozyme. The warping and deformation of the lysozyme bridging were demonstrated by the conversion of its spatial structure from alpha-helix into a beta-sheet, measured by CD. In the presence of nano-TiO(2), the bacteriolysis activity of lysozyme was subjected to an obvious inhibition.. The two-step binding model of lysozyme was proposed, in which lysozyme was adsorbed on nano-TiO(2) particle surface by electrostatic interaction and then the hydrogen bond (N-H...O and O-H...O) formed between nano-TiO(2) particle and polar side groups of lysozyme. The adsorption of lysozyme obeyed the Langmuir isothermal model. The binding of lysozyme is dependent on the acidity and ion strength of the media. The bigger TiO(2) aggregate was formed in the presence of lysozyme where lysozyme may bridge between nano-TiO(2) particles. The coexistence of nano-TiO(2) particles resulted in the transition of lysozyme conformation from an alpha-helix into a beta-sheet and a substantial inactivation of lysozyme. The beta-sheet can induce the formation of amyloid fibrils, a process which plays a major role in pathology.. Lysozyme was adsorbed on the nano-TiO(2) particle surface via electrostatic attraction and hydrogen bonds, and they also bridged among global nano-TiO(2) particles to form the colloidal particles. As a reasonable deduction of this study, nano-TiO(2) might have some toxic impacts on biomolecules. Our data suggest that careful attention be paid to the interaction of protein and nanomaterials. This could contribute to nanomaterial toxicity assessment.. Our results strongly suggest that nano-TiO(2) has an obvious impact on biomolecules. Our data suggest that more attention should be paid to the potential toxicity of nano-TiO(2) on biomolecules. Further research into the toxicity of nanosized particles needs to be carried out prior to their cell toxicity and tissue toxicity. These investigations might serve as the basis for determining the toxicity and application of nanomaterials.

Topics: Hydrogen-Ion Concentration; Metal Nanoparticles; Muramidase; Osmolar Concentration; Protein Conformation; Protein Structure, Secondary; Temperature; Titanium; Toxicity Tests

As the nanotechnology industries increase production, nanoscale products will enter the aquatic environment, posing a possible threat to aquatic organisms. Suspension-feeding invertebrates may represent a unique target group for nanoparticle (NP) ecotoxicity, since they have highly developed processes for the cellular internalisation of nano- and microscale particles (endocytosis and phagocytosis), which are integral to key physiological functions such as intracellular digestion and cellular immunity. In the marine bivalve Mytilus, short-term exposure to nanosized carbon black (NCB) was shown to significantly affect immune parameters of immune cells, the hemocytes, in vitro. In this work, we further investigated the effects of other types of commercial NPs (C60 fullerene, TiO(2) and SiO(2) at 1, 5, 10 microg/ml) on Mytilus hemocytes. Characterization of NP suspensions in artificial sea water (ASW) was performed, indicating the formation of agglomerates of different sizes for different types of NPs. None of the NP tested significantly affected lysosomal membrane stability, indicating the lack of a major toxic effect. However, all NP suspensions induced a concentration-dependent lysozyme release, extracellular oxyradical and nitric oxide (NO) production, to a different extent and with different time courses depending on the concentration and the NP type. The inflammatory effects of NPs were mediated by rapid activation of the stress-activated p38 MAPK. The results further support the hypothesis that in bivalves the immune system represents a significant target for NPs.

Topics: Animals; Fullerenes; Hemocytes; Muramidase; Mytilus; Nanoparticles; Nitric Oxide; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Reactive Oxygen Species; Silicon Dioxide; Time Factors; Titanium; Water Pollutants, Chemical

The monomolecular adsorption of lysozyme (LSZ) and bovine serum albumin (BSA) on hydroxyapatite (HAp) was observed by using two types of fibrous crystals elongated in the c-axis. Selective removal of the specific proteins was achieved by the capture and decomposition on the HAp crystals having the particular nanostructures attached with anatase-type TiO(2). Bundled short nanorods of ca. 10nm in diameter were suitable for the capture of a relatively small protein molecule, LSZ, due to their high specific surface area, while the adsorption of a relatively large molecule, BSA, was restricted because of the narrow clearance gap between the nanorods. On the other hand, the large protein preferentially adsorbed to long nanoneedles of 30-60 nm in diameter, which had a wide gap among the loosely aggregated crystals. The captured proteins were smoothly decomposed with anatase nanoparticles loaded on the fibrous HAp crystals under UV irradiation. Thus, the photocatalytic activity for the decomposition of proteins could be controlled with the adsorption on the surface of the nanostructured HAp crystals.

Topics: Animals; Catalysis; Cattle; Durapatite; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Muramidase; Nanoparticles; Proteins; Serum Albumin, Bovine; Titanium; Ultraviolet Rays; X-Ray Diffraction

A simple, rapid, straightforward and washing/separation free of in-solution digestion method for microwave-assisted tryptic digestion of proteins (cytochrome c, lysozyme and myoglobin) using bare TiO(2) nanoparticles (NPs) prepared in aqueous solution to serve as multifunctional nanoprobes in electrospray ionization mass spectrometry (ESI-MS) was demonstrated. The current approach is termed as 'on particle ionization/enrichment (OPIE)' and it can be applied in ESI-MS, atmospheric pressure-matrix-assisted laser desorption/ionization mass spectrometry (AP-MALDI-MS) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The bare TiO(2) NPs can assist, accelerate and effectively enhance the digestion efficiency, sequence coverage and detection sensitivity of peptides for the microwave-assisted tryptic digestion of proteins in ESI-MS. The reason is attributed to the fact that proteins or partially digested proteins are easily attracted or concentrated onto the surface of TiO(2) NPs, resulting in higher efficiency of digestion reactions in the microwave experiments. Besides, the TiO(2) NPs could act as a microwave absorber to accelerate and enrich the protein fragments in a short period of time (40-60 s) from the microwave experiments in ESI-MS. Furthermore, the bare TiO(2) NPs prepared in aqueous solution exhibit high adsorption capability toward the protein fragments (peptides); thus, the OPIE approach for detecting the digested protein fragments via ESI and MALDI ionization could be achieved. The current technique is also a washing and separation-free technique for accelerating and enriching microwave-assisted tryptic digestion of proteins in the ESI-MS and MALDI-MS. It exhibits potential to be widely applied to biotechnology and proteome research in the near future.

Topics: Animals; Cadmium Compounds; Cattle; Chickens; Cytochromes c; Hot Temperature; Microwaves; Molecular Probes; Muramidase; Nanoparticles; Peptide Fragments; Quantum Dots; Spectrometry, Mass, Electrospray Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Sulfides; Titanium; Trypsin

Electrochemical (EC) quartz crystal microbalance with dissipation monitoring (ECQCM-D) is a new and powerful technique for the in situ study of adsorption phenomena, e.g., as a function of the potential of the substrate. When titanium (Ti) is employed as the substrate, its oxidation behavior needs to be taken into account. Ti is always covered with a native oxide layer that can grow by, e.g., thermal oxidation or under anodic polarization. For biomolecular adsorption studies on oxidized Ti under applied potential, a stable oxide layer is desired in order to be able to distinguish the adsorption phenomena and the oxide growth. Therefore, the oxidation of thermally evaporated Ti films was investigated in phosphate-buffered saline by means of ECQCM-D, using a specially designed EC flow cell. Upon stepping the potential applied to Ti up to 2.6 V vs standard hydrogen electrode (SHE), a fast increase of the mass was observed initially for each potential step, evolving slowly to an asymptotic mass change after several hours. The oxide layer thickness increased as a quasi-linear function of the oxidation potential for potentials up to 1.8 V vs SHE. The growth rate of the oxide was around 2.5-3 nm/V. No changes in the dissipation shift were observed for potentials up to 1.8 V vs SHE. The composition of the oxide layer was analyzed by X-ray photoelectron spectroscopy (XPS). It was mainly composed of TiO(2), with a small percentage of suboxides (TiO and Ti(2)O(3)) primarily at the inner metal/oxide interface. The amount of TiO(2) increased, and that of TiO and Ti(2)O(3) decreased, with increasing oxidation potential. For each oxidation potential, the calculated thickness obtained from ECQCM-D correlated well with the thickness obtained by XPS depth profiling. A procedure to prepare Ti samples with a stable oxide layer was successfully established for investigations on the influence of an electric field on the adsorption of biomolecules. As such, the effect of an applied potential on the adsorption behavior of lysozyme on oxidized Ti was investigated. It was observed that the adsorption of lysozyme on oxidized Ti was not influenced by the applied potential.

Topics: Adsorption; Electrochemical Techniques; Muramidase; Oxidation-Reduction; Oxides; Photoelectron Spectroscopy; Quartz; Surface Properties; Titanium

Topics: Anti-Bacterial Agents; Cell Survival; Crystallization; Enzyme Activation; Enzymes, Immobilized; Micrococcus; Muramidase; Nanostructures; Nanotechnology; Particle Size; Silicon Dioxide; Temperature; Titanium

Bovine serum albumin and lysozyme mixtures of different mole fractions were adsorbed to colloidal alumina (116 nm) and titania particle (271 nm) suspensions of 2 vol % solid content for 16 h at pH 7.5. The total protein amount normalized to the powder surface area was 1000 ng/cm2. The zeta potential of the protein-treated suspensions was measured as a function of pH and the isoelectric point (IEP) obtained. A simple prediction model in two refinement steps was derived and evaluated for the obtained IEPs. The best model fit which takes into account moles of protein and surface fractions yielded an average prediction error of 7.5% and a maximum error of 16.7%.

Topics: Adsorption; Aluminum Oxide; Animals; Colloids; Hydrogen-Ion Concentration; Isoelectric Point; Muramidase; Serum Albumin, Bovine; Surface Properties; Time Factors; Titanium; Water

Changes in the content of lysozyme and copper were studied in the blood serum of rats in four time intervals (1, 2, 12, and 24 weeks) after administration of 50 mg TiO2, Sio2 or coal dust and the copper content was also studied 12 weeks after administration of 3 industrial dusts. The obtained results were supplemented by histopathological examinations and in the 12-week interval by the determination of the lung wet weight. The lysozyme content was statistically significantly increased compared to controls practically over the whole time course with differences in the level of the response to SiO2 in comparison with the response to TiO2 and coal. With the exception of the first interval, the serum copper level was statistically significantly increased only after quartz dust administration. The obtained results were compared with literary data and findings reported from clinical practice.

Topics: Animals; Coal; Copper; Dust; Lung; Male; Muramidase; Rats; Rats, Inbred Strains; Silicon Dioxide; Titanium