Deformation in Metals

<p>Structure/composition</p> Signup and view all the answers

<p>Ionic bond</p> Signup and view all the answers

<p>Van der Waals forces</p> Signup and view all the answers

<p>Low melting point</p> Signup and view all the answers

<p>Atomic Force Microscopy (AFM)</p> Signup and view all the answers

<p>θC &gt; 90° is hydrophobic</p> Signup and view all the answers

<p>Transmission Electron Microscopy (TEM)</p> Signup and view all the answers

<p>Scanning Electron Microscopy (SEM)</p> Signup and view all the answers

<p>Each crystal is a separate grain within the material</p> Signup and view all the answers

<p>Deformation</p> Signup and view all the answers

<p>Surface sensitivity</p> Signup and view all the answers

<p>Implanted devices that exhibit similar mechanical properties to the natural neural environment</p> Signup and view all the answers

<p>Biomimicry closely matches the natural subject, while bioinspiration leverages materials from nature to enhance an engineered system</p> Signup and view all the answers

<p>Permanent synthetic structures causing inflammation and damage over time</p> Signup and view all the answers

<p>Physical, chemical, and electrical alterations</p> Signup and view all the answers

<p>Proteins</p> Signup and view all the answers

<p>Protein conformation</p> Signup and view all the answers

<p>They are not dynamic and living</p> Signup and view all the answers

<p>Near-Field Scanning Optical Microscopy (NSOM)</p> Signup and view all the answers

<p>~ 100 mm</p> Signup and view all the answers

<p>Lateral force mode</p> Signup and view all the answers

<p>Atomic Force Microscopy (AFM)</p> Signup and view all the answers

<p>~ 4 mm</p> Signup and view all the answers

<p>Thermal scanning</p> Signup and view all the answers

<p>Near-Field Scanning Optical Microscopy (NSOM)</p> Signup and view all the answers

<p>Non-contact mode</p> Signup and view all the answers

<p>Atomic Force Microscopy (AFM)</p> Signup and view all the answers

<p>Scanning a very small light source very close to the sample and detecting the light energy forms the image.</p> Signup and view all the answers

<p>NSOM can provide resolution below that of the conventional light microscope.</p> Signup and view all the answers

<p>~ 100 mm</p> Signup and view all the answers

<p>~ 4 mm</p> Signup and view all the answers

<p>~ 20-40 nm</p> Signup and view all the answers

<p>Contact mode</p> Signup and view all the answers

<p>Non-contact mode</p> Signup and view all the answers

<p>Frictional forces</p> Signup and view all the answers

<p>The distribution of thermal conductivity</p> Signup and view all the answers

<p>Biomimicry aims to match the natural subject as closely as possible, while bioinspiration leverages materials, methods, or other cues from nature and applies them toward analogous functions to enhance an engineered system.</p> Signup and view all the answers

<p>Proteins are the first molecules to react to device implantation in the neural context.</p> Signup and view all the answers

<p>Permanent synthetic structures are more likely to cause inflammation and damage over time in the neural context because they are not dynamic and living like the natural neural environment.</p> Signup and view all the answers

<p>The conformation of proteins determines the downstream effects of device implantation in the neural context.</p> Signup and view all the answers

<p>The structure-function relationship of a material determines its function according to the text.</p> Signup and view all the answers

<p>The three types of alterations in implanted devices in the neural context are mechanical, chemical, and electrical alterations.</p> Signup and view all the answers

<p>Permanent synthetic structures are NOT a common biomimetic approach in the neural context.</p> Signup and view all the answers

<p>Some advantages of living systems in dynamically responding to a changing environment include bulk stiffness and flexibility, managing the protein corona, ionic conductors, cell-seeded scaffolding, surface topography, bioactive surfaces, flexible conductors, tissue ingrowth/remodeling, size and form factor, antioxidants and free-radical scavengers, electrically responsive materials, and biodegradable systems.</p> Signup and view all the answers

<p>Some important material properties for medical applications include acoustical properties, atomic properties, chemical properties, electrical properties, environmental properties, magnetic properties, manufacturing properties, mechanical properties, optical properties, radiological properties, and thermal properties.</p> Signup and view all the answers

<p>Some advantages of natural materials in biomaterials include biofunctionality, biodegradability, and less inflammation.</p> Signup and view all the answers

<p>Some advantages of synthetic materials in biomaterials include property tuning and processing.</p> Signup and view all the answers

<p>Some disadvantages of natural materials in biomaterials include mechanical properties, stability, processing, and immunogenicity.</p> Signup and view all the answers

<p>Some disadvantages of synthetic materials in biomaterials include loss of cell function, inflammation, and potential for the loss of cell function.</p> Signup and view all the answers

<p>Some characteristics of ceramics include being nonmetallic and inorganic solids, having ionic bonding, high melting points, great hardness and strength, considerable durability, low electrical and thermal conductivity, and chemical inertness.</p> Signup and view all the answers

<p>The more grain boundaries there are, the more dislocations and plastic deformation are hindered, resulting in increased strength.</p> Signup and view all the answers

<p>Young's equation describes the thermodynamic equilibrium between three phases (gas/air, liquid, and solid) at the interface. It relates the contact angle (θC) to the interfacial energy and provides information about the wettability of the surface. A contact angle less than 90° indicates hydrophilicity, while a contact angle greater than 90° indicates hydrophobicity.</p> Signup and view all the answers

<p>The depth of analysis for FTIR-ATR depends on the refractive index of the ATR scanning element and is typically greater than 0.5 mm. FTIR-ATR provides more information than ESCA but is less surface sensitive.</p> Signup and view all the answers

<p>XPS, also known as ESCA, involves the impingement of X-rays on a sample surface, resulting in the release of core electrons as photoelectrons. The kinetic energy and binding energy of these photoelectrons can be measured and mapped to the parent element/atom, making XPS useful for elemental analysis of polymer surfaces and coatings.</p> Signup and view all the answers

<p>The three most common scanning probe techniques are Atomic Force Microscopy (AFM), Scanning Tunneling Microscopy (STM), and Scanning Probe Microscopy (SPM). AFM measures the interaction force between a tip and surface, STM measures a weak electrical current flowing between a tip and sample, and SPM is very good for surface profiling/ultrastructure/surface interaction analysis.</p> Signup and view all the answers

<p>In SEM, the sample surface is bombarded with electrons, resulting in the excitation and emission of secondary and backscattered electrons from atoms in a small area extending into the sample surface. The emitted electrons are detected as an 'area map' (micrograph) of the characteristic bombarded region.</p> Signup and view all the answers

<p>Light microscopy, including brightfield, darkfield, phase contrast, and fluorescence microscopy, is good for analyzing samples at micron level resolution. It is also useful for cell-material analysis since most cells are in the micron range.</p> Signup and view all the answers

<p>Mechanical properties = Orthopedic Implants Chemical properties = All materials Magnetic properties = MRI compatible materials Thermal properties = Ablation, RF Heat Dissipation</p> Signup and view all the answers

<p>Ionic bond = Electrostatic forces between oppositely charged ions Covalent bond = Sharing of valence electrons between two atoms Metallic bond = Sharing of valence electrons between groups of atoms in 3-D Hydrogen bonding = Secondary bonding, weak intermolecular interaction</p> Signup and view all the answers

<p>Ceramics = High melting points, great hardness and strength, low electrical and thermal conductivity Metals = Conductivity, often used in medical devices Natural materials = Biofunctionality, biodegradable, less inflammation Synthetic materials = Property 'tuning', processing, can cause inflammation and loss of cell function</p> Signup and view all the answers

<p>Natural materials = Proteins: collagen, fibrin, elastin Synthetic materials = Polymers: polyurethanes, PTFE, PE, polysiloxanes Ceramics = HA, bioactive glasses Metals = Ti/Ti-alloys, Co-Cr alloys, stainless steel</p> Signup and view all the answers

<p>Ionic bonds = Ceramics Covalent bonds = Polymers, organics Metallic bonds = Metals Hydrogen bonds = Intermolecular interactions</p> Signup and view all the answers

<p>Electrical properties = Neuromodulation, Stimulation Manufacturing properties = All materials, Processing Radiological properties = Intraoperative Imaging Optical properties = Contact Lenses</p> Signup and view all the answers

<p>Natural materials = Biofunctionality, biodegradable, less inflammation Synthetic materials = Property 'tuning', processing Ceramics = High melting points, great hardness and strength, low electrical and thermal conductivity Metals = Conductivity, often used in medical devices</p> Signup and view all the answers

<p>Biomimicry = Approach to match the natural subject as closely as possible Biocompatibility = Ability of a material to perform with an appropriate host response in a specific application Bioinspiration = Approach that leverages materials, methods, or other cues from nature to enhance an engineered system Inflammation = A protective response involving immune cells, blood vessels, and molecular mediators</p> Signup and view all the answers

<p>Physical = Brain features are small and mechanically pliant Chemical = Proteins are the first molecules to react to device implantation Electrical = Neural tissues are excitable by ionic currents</p> Signup and view all the answers

<p>StructureFunction = Materials aspect of bioMATERIALS Material Selection / Design = Process of choosing materials based on their properties for specific applications Tissue Engr. = Engineering of tissues for medical purposes Drug Delivery = Method of delivering drugs to a patient in a manner that increases the concentration of the drug in some parts of the body relative to others</p> Signup and view all the answers

<p>Biomimetic = Derived from living forms, mimics the structure or function of a biological entity Bio-Inspired Biomaterials = Materials inspired by biological processes and structures Neural Context = Referring to the nervous system Scale NanoMacro = Refers to the scale from nano (very small) to macro (very large)</p> Signup and view all the answers

<p>Protein-Material Interactions = Interactions between proteins and materials that influence the performance of a material Cell-Material Interactions = Interactions between cells and materials that influence the performance of a material Blood Compatibility = The ability of a material to perform with an appropriate host response in blood-related applications Orthopedic Applications = Use of materials in the treatment of musculoskeletal disorders</p> Signup and view all the answers

<p>Biomimicry = An approach that attempts to emulate nature's strategies and principles to solve human problems Bioinspiration = An approach that uses ideas from nature to improve engineering systems Neural Context = Referring to the nervous system Biomaterials = Materials used in contact with the human body for medical purposes</p> Signup and view all the answers

<p>Bio aspect of BIOmaterials = The biological component of materials used in medicine Materials aspects of bioMATERIALS = The physical properties and behaviors of materials used in medicine Neural = Relating to the nervous system Orthopedic = Relating to the branch of medicine dealing with the correction of deformities of bones or muscles</p> Signup and view all the answers

<p>NSOM = Scans a small light source very close to the sample AFM = Uses a cantilever and tip for imaging AFM (contact mode) = Has a strong (repulsive) force of interaction AFM (non-contact mode) = Has a weak (attractive) force of interaction</p> Signup and view all the answers

<p>Contact mode = Strong (repulsive) Non-contact mode = Weak (attractive) Lateral force mode = Frictional forces exert a torque on the scanning cantilever Magnetic force mode = Images the magnetic field of the surface</p> Signup and view all the answers

<p>Cantilever length = ~ 100 mm Tip diameter at cantilever interface = ~ 4 mm Tip diameter at apex = ~ 20-40 nm</p> Signup and view all the answers

<p>Contact mode = Strong (repulsive) Non-contact mode = Weak (attractive) Lateral force mode = Frictional forces exert a torque Thermal scanning mode = Images the distribution of thermal conductivity</p> Signup and view all the answers

<p>NSOM = Can provide resolution below that of the conventional light microscope AFM = Can image the distribution of thermal conductivity when operating in thermal scanning mode</p> Signup and view all the answers

<p>Cantilever = ~ 100 mm long Tip at cantilever interface = ~ 4 mm dia Tip at apex = ~ 20-40 nm dia</p> Signup and view all the answers

<p>Contact mode = Strong (repulsive) Non-contact mode = Weak (attractive) Lateral force mode = Frictional forces exert a torque on the scanning cantilever</p> Signup and view all the answers

<p>AFM (contact mode) = Maintains constant force or distance NSOM = Scans a small light source very close to the sample AFM = Uses a cantilever and tip for imaging AFM (non-contact mode) = Uses a vibrating probe</p> Signup and view all the answers

<p>Contact mode = Strong (repulsive) force of interaction Non-contact mode = Weak (attractive) force of interaction Lateral force mode = Frictional forces exert a torque on the scanning cantilever Magnetic force mode = Images the magnetic field of the surface</p> Signup and view all the answers

<p>Scanning Electron Microscopy (SEM) = Sample surface is bombarded with electrons, creating an 'area map' of the bombarded region Light Microscopy = Good for analyzing samples at micron level resolution Scanning Probe Microscopy (SPM) = Very good for surface profiling/ultrastructure/surface interaction analysis X-ray Photoelectron Spectroscopy (XPS) = Useful for elemental analysis of polymer surfaces and coatings</p> Signup and view all the answers

<p>Slip = Allows plastic deformation without breaking an entire plane of atoms at once, common in metals Young's Equation = Describes the thermodynamic (energy) equilibrium between three phases at the interface Polycrystalline materials = Materials with many crystals, each crystal is a separate grain within the material Contact Angle = The angle at which a fluid interface meets a solid surface</p> Signup and view all the answers

<p>Atomic Force Microscopy (AFM) = Measures the interaction force between the tip and surface Scanning Tunneling Microscopy (STM) = Measures a weak electrical current flowing between tip and sample Surface profiling = A process that involves scanning the surface of a material to obtain its profile Ultrastructure = The detailed structure of a biological specimen, such as a cell, tissue, or organ, that is visible only with an electron microscope</p> Signup and view all the answers

<p>Hydrophilic = Describes a surface that has a contact angle less than 90 degrees Hydrophobic = Describes a surface that has a contact angle greater than 90 degrees Interfacial energy = Can be measured using the contact angle Wettability = A property of a surface that can be inferred from the contact angle</p> Signup and view all the answers

<p>Light Microscopy = Good for cell-material analysis since most cells are in the micron range Scanning Electron Microscopy (SEM) = Useful for examining the surface of a material Scanning Probe Microscopy (SPM) = Excellent for surface profiling and surface interaction analysis X-ray Photoelectron Spectroscopy (XPS) = Very useful for elemental analysis of polymer surfaces and coatings</p> Signup and view all the answers

<p>Dislocation = Can transit across grain boundaries, but very difficult Slip = Allows plastic deformation without breaking an entire plane of atoms at once Grain boundaries = The interface where crystals of different orientations meet within a polycrystalline material Ductility = A measure of a material's ability to undergo significant plastic deformation before rupture</p> Signup and view all the answers

<p>Depth of analysis = Depends on refractive index of ATR scanning element in FTIR-ATR Surface Energy = Can be determined using Young's Equation X-ray Photoelectron Spectroscopy (XPS) = Also called Electron Spectroscopy for Chemical Analysis (ESCA) Trade-offs = Considerations such as depth, spatial resolution and cost in surface characterization techniques</p> Signup and view all the answers