31

Nanotoxikologie (Fach) / Teil 1 (Lektion)

Diese Lektion wurde von punkbeat89 erstellt.

Lektion lernen

Diese Lektion ist leider nicht zum lernen freigegeben.

zurück  |  weiter 1 / 1

• Give a short definition of monodispers! dispersions, where all particles have the same size
• Give a short definition of polydispers! dispersions, where particles have different sizes
• a) Give a short definition of ultrafine particles! b) Give a short definition of aerosol! c) Give a short definition of particulate matters! a) usually incidentally produced particles in air (max. 0,1μm) b) fine distributed liquid or solid particles in air (max. 0,001-100μm) c) atmospheric particles (max. 2,5-10μm)
• a) Give a short definition of colloids! b) What is the main difference between colloids and nanoparticles? a) Colloidal systems consist of a dispersed (or discontinuous) phase which is uniformly distributed in a finely divided state in a dispersion medium (or continuous phase) b) size distribution is more spreaded => can be from μm to nm
• a) What are intrinsic properties of nanoparticles? b) What are extrinsic properties of nanoparticles? a) •properties of the material itself => depends on the material b) •nanoparticles with different surfaces => depends on the system where the NP are embedded in
• a) Give a short definition of aggregation! b) Give a short definition of agglomeration! c) Give a short definition of sedimentation! a) •a set of particles composed of strongly linked or bonded particles b) •a mass of particles (or aggregates, or both) that adhere to each other with weak physical bonds or that are entwined together (case of nanotubes, for example) c) settling of suspended particles or aggregates (by gravity or centrifugal field)
• Please mention the nanoobjects! Nanoparticles Nanoplates Nanorods
• What are the subcategories of Nanorods? Nanotubes Nanowires Nanofibers
• What are the subcategories of nanostructured materials? Nanocomposites => Material containing NP Materials with nanoscaled surface structures
• a) Give a short definition of nanocomposites! b) Can you explain the Lotus effect of Materials with nanoscaled surface structures? a) •multiphase solid material where one of the phases has one, two or three dimensions of less than 100 nanometers (nm), or structures having nano-scale repeat distances between the different phases that make up the material b) •surface that contains nanoparticles forming tiny air bags, on which the liquids flow down without penetrating the surface
• Anzeige
• a) Give a short definition of nanoparticles! b) Give a short definition of nanorods! c) Give a short definition of nanoplates! a) •nano object with 3 dimensions with nano size => discrete nano object b) •solid nanofiber with 2 dimension on the nanometric scale + 1 with bigger dimension c) •nano object with 1 dimensions on the nanometric scale + 2 with bigger dimension
• a) Give a short definition of nanofibers! b) Give a short definition of nanotubes! c) Give a short definition of nanowires! a) •nano object with 2 dimensions on the nanometric scale + 1 with bigger dimension b) •a hollow nanofibre with 2 dimension on the nanometric scale + 1 with bigger dimension c) •a Nanofiber which is electrically conducting or semiconducting 2 dimension on the nanometric scale + 1 with bigger dimension
• a) Can you give some examples of natural nanoparticles? b) Can you give some examples of incidental nanoparticles? c) Can you give some examples of engineered nanoparticles? a) •mineral composites•volcanic ash•viruses•sea spray b) •Diesel exhaust (Dieselabgase)•welding fumes (Schweißrauch)•industrial effluents (Industrieabwässer)•Sandblasting (Sandstrahlen) c) •metals•Quantum dots•Bucky Balls/Nanotubes•sunscreen pigments•nanocapsules
• a) What is the „Woodrow Wilson inventory“? b) What is the main problem with the WWI? a) •database of commercial products containing NP b) •not verified by a department or an authority
• Can you give a general overview about nanomaterials? Carbon-based nanomaterials•Carbon black nanoparticles•Carbon nanotubes (CNTs)=> single-walled (SWCNT) => multi-walled (MWCNT) Fullerene-type (Cn) n= 60, 70 or higher Metal nanoparticles silver, gold nanoparticles Metall oxidesTiO2, ZnO, CeO2, SiO2, Fe2O3 Core-shell structures Quantum dots Polymer NP•Dendrimer type (highly branched structures, based on poly-amidoamines => PAMAMs)•PLGA (poly-D, L-lactide-co-glycolide) or PLA-PGA-type  (poly-lactide acid, poly-L-glutamic acid)•Polysaccharide-type (e.g. nanocellulose) Micelles Liposomes 
• Can mention at least 5 applications for the usage of Nanoparticles in commercial products? •Cosmetic Products•Personal Care•Food Contact Materials•Food Additives/“Supplements” •Textiles•Fuel Additives•Medical Sector•Paints
• Can you give an short explanation about Nanoclay? •are NP containing clay stone compounds (Si, Al etc.)•tortuous path => a lot of clay layers are embedded in plastic → saving of material; increased material, chemical and thermic stability; increased barrier property (higher storability of food e.g. used in beer bottles)
• For what kind of applications can be silver nanoparticles used? •mainly used because of their bactericidal properties (in food packages, textile fibers)
• What kind of applications do you know for TiO2? ZnO? Fe2O3? SiO2? a) •mainly for UV protection, photocatalyst: (e.g. self cleaning glass, water disinfection) b) •mainly for UV protection c) •superparamagnetic•used in catalysis, as sensors, in bioimaging (MRI = MRT) d) •food additive (non- nano with nanoscaled fraction!) •anti- caking agent (e.g. cosmetics, packaging etc.)
• a) What kind of methods do you know for the stabilization of NP? b) Why do we need a stabilization? c) Can you give for each method at least one example? d) What is the overall principle behind the stabilization? a) •charge and steric stabilization b) •NP are not stable per se => they can form agglomerates c) •charge stabilization: with citrate salts•steric stabilization: with polymers (e.g. PVP) d) •Stability is achieved by a balance of repulsive & attractive forces
• a) Can you briefly explain the shown curve? b) What are variability factors the zeta potential is depending on? c) What kind of assertion can we make in consequence of the results of a zeta potential measurement? a) •At the beginning the Nernst potential of the particle surface is determining the electric potential → a linear increase of the negative potential is caused,  by adsorption of additional negative particles (= potential of the inner Helmholtz layer) → the potential of the outer Helmholtz layer is decreasing in consequence of the positive rigid  strongly bond Helmholtz layer on the NP surface (Stern potential = potential of the outer Helmholtz layer)•approximately 5% of the diffuse layer are keeping their negative charge, because they’re remaining unaffected by the positive ions → the Stern-Potential is decreasing exponentially in the diffuse layer (inordinate array of counterions ) → at the shear plane there results a shearing of the diffuse layer (shearing plane) by particle migration and the resulting  friction→ the particle that was neutral before, is turning into a charged ion => the point there you can measure the zeta potential at the shearing of plane b) •pH •Ion strength, concentrations c) •stability of the NP suspension => the higher the number, the more stable it is
• a) What is the principle behind the DLS? b) How can we interpret a result of a DLS measurement? c) Let’s imagine, that we measure our hydrodynamic diameter via DLS with a light (λ= 550nm). Is it possible to measure a NP with a size of 100nm with this wavelength? d) If you compare two resulting curves, you can just notice that one of them have a higher fluctuation. Which of them show the smaller particle? a) •DLS instruments that measure at a fixed angle can determine the mean particle size in a limited size range → From a microscopic point of view the particles scatter the light and thereby imprint information about their motion → Analysis of the fluctuation of the scattered light thus yields information about the particles b) •by measuring the decay rate of the light intensity (Γ) Γ=q2*D, a DLS correlator can calculate the diffusion coefficient, since it’s directly related to the diffusion coefficient•with the Stokes-Einstein equation, we can calculate our hydrodynamic diameter of the NP c) •No, because the NP is at least (NP diameter < 1/20 λ) 20x smaller than the wavelength d) •b shows the smaller particle => it cause faster fluctuations (as they move faster) •thus, the correlation decreases more rapidly
• We just look at the uptake via cosmetics, clothes: a) What is the name of this kind of uptake route? b) What is the primary target organ? a) dermal route b) skin
• We just look at the uptake via nanomedicine: a) What is the name of this kind of uptake route? b) What is the primary target organ? c) What is the first relevant biofluid? a) injection i.v. b) blood c) blood plasma
• We just look at the uptake via spray products, air: a) What is the name of this kind of uptake route? b) What is the primary target organ? c) What is the first relevant biofluid? a) inhalation b) respiratory tract (nasal/tracheo-bronchial/alveolar) c) lung lining fluid (mainly phospholipids)
• We just look at the uptake via food: a) What is the name of this kind of uptake route? b) What is the primary target organ? c) What is the first relevant biofluid? a) Ingestion route b) GI-tract c) gastric juices
• a) How can we measure the thickness of protein layers? b) Is a measured diameter enhancement of 100nm reasonable. If not what would you do to proof this result? a) •techniques that measure the hydrodynamic size of a NP (not only the core) => e.g. Dynamic Light Scattering (DLS) b) •enhancements of 10-30nm due to protein absorption are usual => a agglomeration might happened, which makes a verification of the assumption via Zeta potential necessary
• a) How can we measure the amount of bound proteins? b) How can we identify the bound proteins? a) •Colorimetric assays (e.g. Bradford) b) •the sample of NP bound to proteins is diluted in a fluid and incubated with the Bradford dye•centrifugation of the sample => analyze supernatant  (NP + protein corona => measure protein depletion)  or just analyze NP pellet•Washing & Elution of protein (3x centrifugation) + out reading of the absorbance (at 595nm) => amount of the bound proteins can be found out by to creating a standard curve with a standard (e.g. BSA)
• a) How can we get information of the conformation of the proteins? b) How can you actually draw an inference of the spectra of those two methods? a) •Circular Dichroism, Fluorescence spectroscopy b) •CD: When the chromophores of the amides of the polypeptide backbone of proteins are aligned in arrays, their optical transitions are shifted or split into multiple transitions due to “exciton” interactions => different structural elements have characteristic CD spectra e.g. α-helical proteins have negative bands at 222 nm and 208 nm and a positive band at 193 nm•FES: aromatic amino acids can be measured => dependency of the local environment (quenching effects of other amino acids as energy transfer to the aromatic amino acid can change the emission)
• a) How can we get information of the identity of the proteins? b) How can we draw an inference of what kind of protein we have? a) •Gel-Electrophoresis (SDS-PAGE) → Western Blot => single-protein identification •Gel-Electrophoresis (SDS-PAGE) → Coomassie staining → Mass spectroscopy => multi-protein identification b) •protein is moving in dependence of it’s electrophoric mobility, molar mass and size => the dye colors the separated protein bands => with MS we can then identify them exactly
• Anzeige
• a) How can we get information of the stability of the binding proteins? b) So when the protein binds with a high affinity, what kind of conclusion can you think of? a) •Isothermal Titration Calometry b) •usually the reaction is of exothermic nature => sample cell gets hotter than the reference cell (Peak end is vertical) => if the temperature difference between the cell is decreasing near 0 the peak is approximating to the base line•a protein-NP-bound which is not stable, will have a planar titration curve, so the AUC would be very small => high affinity = great AUC

zurück  |  weiter 1 / 1