EMA4061 Biomaterials: Structure and Properties Exam 1

structural

Identify the protein function.

Components of the ECM that physically support cells. Examples include: collagen, elastin, fibronectin, laminin, and vitronectin.

enzyme

Identify the protein function.

Catalyzes reactions by stabilizing the transition state to lower the activation energy of a reaction. Examples include urease.

transport

Identify the protein function.

Bind and deliver specific molecules to cells, tissues, and organs. Examples include hemoglobin and serum albumin.

motility

Identify the protein function.

Provide mechanisms for cell motion. Examples include actin and myosin.

defense

Identify the protein function.

Participate in the immune response and coagulation mechanisms. Examples include fibrinogen and thrombin.

regulatory

Identify the protein function.

Cytokines that regulate cell activities. Examples include insulin.

collagen

Identify the protein.

• A structural protein.
• Fibrillar, cross-linked, and organized into fibrils.
• Provides tensile strength to the tissue.

elastin

Identify the protein.

• A structural protein.
• Produced by fibroblasts and smooth muscle cells.
• Abundantly found in the blood vessels, lungs, skin, and ligaments.
• Provides elasticity to the tissue.

fibronectin

Identify the protein.

• A structural protein.
• A glycoprotein bonded to a glycosaminoglycan.
• Supports cell migration through the extracellular matrix by connecting cells with collagen fibers.

laminin

Identify the protein.

• A structural protein.
• A glycoprotein bonded to a glycosaminoglycan.
• Assists in cell adhesion.
• Vitronectin has a similar function.

vitronectin

Identify the protein.

• A structural protein.
• A glycoprotein bonded to a glycosaminoglycan.
• Assists in cell adhesion.
• Laminin has a similar function.

urease

Identify the protein.

• An enzymatic protein.
• Catalyzes the hydrolysis of urea.

hemoglobin

Identify the protein.

• A transport protein.
• Carries oxygen to tissues.

serum albumin

Identify the protein.

• A transport protein.
• Transports fatty acids.

actin

Identify the protein.

• A motile protein.
• Found in muscle tissue.
• Myosin is another component found in muscle tissue.

myosin

Identify the protein.

• A motile protein.
• Found in muscle tissue.
• Actin is another component found in muscle tissue.

immunoglobulin

Identify the protein.

• A defensive protein.
• Y-shaped, binds to antigens (foreign proteins), and induces aggregate formation.
• Also known as an antibody.

fibrinogen

Identify the protein.

• A defensive protein.
• Induces clots by platelet receptor binding.
• Thrombin has a similar function

thrombin

Identify the protein.

• A defensive protein.
• Induces clots by platelet receptor binding.
• Fibrinogen has a similar function.

insulin

Identify the protein.

• A regulatory protein.
• Regulates sugar metabolism.

growth factor

Identify the protein.

• A regulatory protein.
• Regulates cell growth and proliferation.

affinity for water

Identify the adsorption protein property.

• A protein with external hydrophilic domains will have better affinity to a hydrophilic surface.
• A protein with external hydrophobic domains will have better affinity to a hydrophobic surface.

size

Identify the adsorption protein property.

• Smaller proteins have higher motility but lower affinity via less contact points with the surface.
• Larger proteins have lower motility but higher affinity via more contact points with the surface.
• See also: Vroman effect.

charge

Identify the adsorption protein property.

• Oppositely-charged proteins and surfaces will attract.
• Protein adsorption is increased at the isoelectric point via minimized electrostatic repulsion and lower affinity for water.

stability

Identify the adsorption protein property.

• More reactive proteins exhibit greater unfolding and greater affinity for surface adsorption.

affinity for water

Identify the adsorption surface property.

• A hydrophobic surface tends to adsorb more proteins.
• A hydrophilic surface tends to resist protein adsorption due to water solvation effects.

charge

Identify the adsorption surface property.

• Opposite charges between the surface and protein promote adsorption.
• Like charges tend to reduce adsorption.

topography

Identify the adsorption surface property.

Increased roughness and topological features increase surface area for proteins to adsorb to.

chemistry

Identify the adsorption surface property.

• Surface functionalization influences adsorption of specific proteins.
• This dictates the types of bonds that the protein and biomaterial surface make.

contact angle

Identify the surface characterization technique.

• Can measure surface dynamics and roughness.
• Liquid wetting of surfaces is used to estimate the surface energy, wettability, and ease of adhesion to a surface.
• Inexpensive and easy.

XPS

Identify the surface characterization technique.

• Can measure chemical composition and molecular structure.
• Electron bombardment of the biomaterial.
• A wide scan reveals chemical composition.
• A narrow scan reveals the chemical state (molecular structure) of an element.
• An expensive technique; a vacuum is required.
• Also known as ESCA.

SIMS

Identify the surface characterization technique.

• Can measure chemical composition, molecular structure, and depth inhomogeneity.
• Secondary ion bombardment of the biomaterial.
• The static variant can reveal elemental and molecular profiles of the surface
• An expensive technique; a vacuum is required.
• The destructive dynamic variant can generate an elemental depth profile.

SEM

Identify the surface characterization technique.

• Can measure lateral and depth inhomogeneity.
• An electron beam probes the surface.
• The specimen must be prepared properly.
• An expensive technique; a vacuum is required.

AFM

Identify the surface characterization technique.

• Can measure roughness and lateral inhomogeneity
• A cantilever beam probes the surface using deflections from secondary interactions.
• Maps the topography to atomic resolutions.

single protein assay

Identify the protein analytical technique.

• Measures adsorption rates and conformation changes of proteins.
• An isolated protein in a buffer solution.

multiple protein assay

Identify the protein analytical technique.

• Evaluates competitive adsorption and protein–protein interactions on a biomaterial surface exposed to a complex media.
• More realistic to mimic implant conditions.

depletion study

Identify the protein analytical technique.

Measures protein adsorption on biomaterial via protein concentration in the supernatant for retroactive determination.

selective depletion study

Identify the protein analytical technique.

• Isolates a single protein and evaluates how its absence affects protein adsorption.
• An example would be afibrinogenemic plasma, lacking fibrinogen.

QCMD

Identify the protein analytical technique.
• Frequently used to evaluate protein–metal interactions.
• A surface characterization technique.

methyl

Identify the surface functionalization group.

• Neutral and hydrophobic.
• Increases affinity to fibrinogen (clotting) and immunoglobulins (immune response).
• Promotes leukocyte adhesion.

hydroxide

Identify the surface functionalization group.

• Neutral and hydrophilic.
• Decreases affinity for plasma proteins.
• Induces exposure of cell adhesion domains on fibronectin.

amino

Identify the surface functionalization group.

• Positively-charged and hydrophilic.
• Increases affinity for fibronectin.
• Triggers an acute inflammatory response.

carboxyl

Identify the surface functionalization group.

• Negatively-charged and hydrophilic.
• Increases affinity for fibronectin and albumin.

glycosaminoglycan

Identify the ECM component.

• Long, unbranched polysaccharides that are highly polar and hydrophilic.
• Can be classified as proteoglycans or hyaluronic acid.
• Acronym: GAG.

proteoglycan

Identify the ECM component.

• A negatively-charged GAG with a covalently linked protein.
• Found primarily in connective tissue.
• Binds to cations and water; regulates molecular movement.
• Examples include heparan sulfate, keratin sulfate, and chondroitin sulfate.

heparan sulfate

Identify the ECM component.

• A type of proteoglycan.
• Binds to cells to regulate their activity.

keratin sulfate

Identify the ECM component.

• A type of proteoglycan.
• Binds to the ECM and acts as a cushion to absorb mechanical shock (such as in cartilage).

chondroitin sulfate

Identify the ECM component.

• A type of proteoglycan.
• Binds to the ECM and provides resistance to compression by using electrostatic repulsion (such as in cartilage).

hyaluronic acid

Identify the ECM component.

• An extremely large GAG allowing other proteoglycans to bind to.
• Also present in holding open areas to allow for cell migration.
• May be removed by hyaluronidase to close areas after cell migration.

compound microscope

Identify the historical concept.

• 1590.
• Janssen invented this.

fluid mosaic model

Identify the historical concept.

• 1972.
• Singer and Nicolson proposed this.