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What happens when biomaterials come into contact with blood or other body fluids?
What happens when biomaterials come into contact with blood or other body fluids?
Cells directly interact with the bare surface of a biomaterial.
Cells directly interact with the bare surface of a biomaterial.
False
What can happen to proteins upon adsorption to a biomaterial?
What can happen to proteins upon adsorption to a biomaterial?
They can change conformation and function
The adsorption of proteins on biomaterials depends on the surface properties of the biomaterial and the _______ of the fluid.
The adsorption of proteins on biomaterials depends on the surface properties of the biomaterial and the _______ of the fluid.
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Match the surface type with its description:
Match the surface type with its description:
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What is the importance of characterizing proteins at surfaces?
What is the importance of characterizing proteins at surfaces?
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Storage conditions do not affect protein adsorption on implant surfaces.
Storage conditions do not affect protein adsorption on implant surfaces.
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________ and hydrophilicity play significant roles in osseointegration.
________ and hydrophilicity play significant roles in osseointegration.
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What are the two main components of the total potential energy (Vtotal) in the DLVO theory?
What are the two main components of the total potential energy (Vtotal) in the DLVO theory?
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According to the provided text, proteins can always be accurately modeled as colloidal particles in adsorption studies.
According to the provided text, proteins can always be accurately modeled as colloidal particles in adsorption studies.
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Besides bulk and surface protein concentration, what are two other factors that affect protein adsorption and desorption, according to the text?
Besides bulk and surface protein concentration, what are two other factors that affect protein adsorption and desorption, according to the text?
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Protein adsorption behavior tends to follow a pattern similar to the ______ isotherm.
Protein adsorption behavior tends to follow a pattern similar to the ______ isotherm.
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Match the terms with their descriptions, in the context of protein adsorption:
Match the terms with their descriptions, in the context of protein adsorption:
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What is the primary focus of the research mentioned in the presentation?
What is the primary focus of the research mentioned in the presentation?
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The Vroman effect is fully explained by the DLVO theory.
The Vroman effect is fully explained by the DLVO theory.
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What type of cells primarily mediate the foreign body reaction following implantation?
What type of cells primarily mediate the foreign body reaction following implantation?
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The foreign body reaction is the end-stage response of the inflammatory and wound healing processes following implantation of a medical device, prosthesis, or ___________.
The foreign body reaction is the end-stage response of the inflammatory and wound healing processes following implantation of a medical device, prosthesis, or ___________.
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According to the provided text, what is a key consequence of protein adsorption on biomaterials?
According to the provided text, what is a key consequence of protein adsorption on biomaterials?
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Which of the following is NOT a teaching objective mentioned?
Which of the following is NOT a teaching objective mentioned?
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Match each term with its description:
Match each term with its description:
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The goal of the research mentioned in the presentation is to completely eliminate protein adsorption on biomaterials.
The goal of the research mentioned in the presentation is to completely eliminate protein adsorption on biomaterials.
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What structural level is mediated by the sum of all local interactions in a protein?
What structural level is mediated by the sum of all local interactions in a protein?
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Approximately how many milligrams per milliliter is the total protein concentration in native blood?
Approximately how many milligrams per milliliter is the total protein concentration in native blood?
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The major components of blood plasma with concentrations greater than 1mg/ml are referred to as the 'big ______'.
The major components of blood plasma with concentrations greater than 1mg/ml are referred to as the 'big ______'.
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Match the following proteins with their approximate concentration range in blood plasma:
Match the following proteins with their approximate concentration range in blood plasma:
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Which of these proteins has the largest molecular weight?
Which of these proteins has the largest molecular weight?
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Protein adsorption to a surface occurs over several hours.
Protein adsorption to a surface occurs over several hours.
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What is the approximate molecular weight of Albumin?
What is the approximate molecular weight of Albumin?
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The displacement of ______ from a hydrophilic surface represents a large energy barrier to protein adsorption.
The displacement of ______ from a hydrophilic surface represents a large energy barrier to protein adsorption.
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What are the primary factors that drive protein adsorption, despite the energy barrier created by water displacement?
What are the primary factors that drive protein adsorption, despite the energy barrier created by water displacement?
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Which of the following is NOT a basis for protein separation in chromatography?
Which of the following is NOT a basis for protein separation in chromatography?
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In an ELISA, the primary antibody is always directly conjugated with the enzyme.
In an ELISA, the primary antibody is always directly conjugated with the enzyme.
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What is used to detect signals in ELISA after an enzyme produces them?
What is used to detect signals in ELISA after an enzyme produces them?
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In chromatography, the mixture of proteins is passed through a column containing a porous solid ______.
In chromatography, the mixture of proteins is passed through a column containing a porous solid ______.
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Match the following terms with their descriptions:
Match the following terms with their descriptions:
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In ELISA, what can the primary antibody be attached to?
In ELISA, what can the primary antibody be attached to?
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Proteins flow through a chromatography system at the same rate.
Proteins flow through a chromatography system at the same rate.
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What are the secondary antibodies conjugated with in an ELISA?
What are the secondary antibodies conjugated with in an ELISA?
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Which of the following is an advantage of using ELISA?
Which of the following is an advantage of using ELISA?
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Fluorescence microscopy is mentioned as a method for surface energy measurement.
Fluorescence microscopy is mentioned as a method for surface energy measurement.
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What type of light is used in ellipsometry to analyze adsorbed protein layers?
What type of light is used in ellipsometry to analyze adsorbed protein layers?
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In QCM, changes in resonance frequency are proportional to the ______ mass.
In QCM, changes in resonance frequency are proportional to the ______ mass.
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Match the measurement technique with its primary feature:
Match the measurement technique with its primary feature:
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Which of these is a limitation of using ELISA?
Which of these is a limitation of using ELISA?
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OWLS technology requires specialized optical waveguides for measurements.
OWLS technology requires specialized optical waveguides for measurements.
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What does 'in situ' mean in the context of ellipsometry?
What does 'in situ' mean in the context of ellipsometry?
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The contact angle measurement is used for determining the ______ energy of a surface.
The contact angle measurement is used for determining the ______ energy of a surface.
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Match the method with the type of information it provides:
Match the method with the type of information it provides:
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What does the lateral resolution of ellipsometry imaging reach?
What does the lateral resolution of ellipsometry imaging reach?
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QCM is able to differentiate between water entrapped within the protein layer and the protein mass.
QCM is able to differentiate between water entrapped within the protein layer and the protein mass.
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What type of surfaces are necessary for ellipsometry measurements?
What type of surfaces are necessary for ellipsometry measurements?
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OWLS measures the change in the ______ upon protein adsorption.
OWLS measures the change in the ______ upon protein adsorption.
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Match the method to whether it is label-free or not:
Match the method to whether it is label-free or not:
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Study Notes
Biocompatible Materials - Proteins and Materials
- Biomaterials interact with proteins/biomolecules upon contact with blood or body fluids. This interaction depends on the biomaterial's surface properties and the composition of the fluid.
- Cells interact with the adsorbed protein layer, not the bare biomaterial surface.
- Protein conformation and function can change upon adsorption to a biomaterial.
Why Characterize Proteins at Surfaces?
- Proteins are the first molecules to interact with biomaterials.
- Cell adhesion factors, like proteins, allow cells to bind to biomaterial surfaces.
- Proteins mediate cellular responses, such as cytokine release.
Drastic Differences in Dental Implant Surfaces
- Dental implant surfaces vary in storage conditions (e.g., SLA, SLActive, fibers, mineralized).
- Significant differences exist in blood and bone cell interactions with these surfaces in vivo.
- Hydrophobic versus hydrophilic surfaces affect protein adsorption and subsequent cell behavior differently.
Protein Adsorption in Biomaterials Design
- Foreign body response and encapsulation are common consequences of protein adsorption in biomaterials.
- The formation of a foreign body capsule can affect device performance and function.
- Methods are studied to prevent or minimize protein adsorption.
Teaching Objectives
- Discuss the foreign body reaction and its association with protein adsorption on biomaterial surfaces.
- Explore the Vroman effect, with emphasis on the basic concept and DLVO theory limitations in interpreting protein adsorption to surfaces.
- Introduce the basic components of blood plasma
- Define the various techniques used to study protein adsorption.
- Examine the advantages and disadvantages of different protein adsorption analysis methods.
- Summarize the foreign body reaction and macrophage functions associated with the reaction
Protein Adsorption by Macrophages
- Macrophages are long-lived phagocytic cells.
- They extend filopodia to attach to bacterial surfaces.
- Bacteria are then engulfed into vacuoles that fuse with lysosomes.
- Lysosomes kill bacteria via reactive oxygen species or proteolytic enzymes.
- Some macrophages are stationary in tissues (e.g., lymph nodes, lungs, liver), where they interact with proteins.
Macrophage Differentiation and Activation
- Macrophages differentiate and activate on biomaterial surfaces.
- Monocytes migrate to the biomaterial/tissue interface.
- Chemotaxis, adhesion, differentiation, signal transduction, and activation drive macrophage development
- Macrophage activity and phenotypic expression are triggered by this process, crucial for subsequent tissue interactions
Host Response to Implant Surfaces
- Protein adsorption and matrix deposition are initial phases, following implantation.
- This process involves various cells including neutrophils, monocytes, and macrophages.
- The final stage often involves the formation of a fibrous capsule.
Protein Basic Facts
- Proteins demonstrate a wide variety of functions and structures.
- Cell surface proteins, structural proteins (e.g., cytoskeleton, ECM), and DNA-binding proteins are examples of various protein types.
- Proteins form enzymes critical to cellular functions and reactions.
- Various proteins comprise about half of a cell's dry mass, crucial for diverse cellular processes.
Amino Acids - Protein Building Blocks
- The genetic code defines the identity of the 20 natural amino acids.
- Adjacent amino acids are linked together by peptide bonds, forming polypeptide chains.
- Amino acid properties influence protein shape, function, and behavior
Amino Acid Sequence and Protein Shape/Function
- Amino acid sequences control and dictate protein structure and properties.
- Interactions of polypeptide chains with solvents help proteins to fold.
- Polar side chains project outward, interacting with the solvent, whereas hydrophobic side chains are often buried.
- Hydrogen bonding stabilizes the protein's folded shape.
Protein Structure/Folding
- Proteins consist of chains of amino acids.
- Primary structure refers to the amino acid sequence.
- Secondary structure includes α-helices and β-sheets stabilized by hydrogen bonds.
- Interactions between secondary structure elements generate tertiary structures, ultimately resulting in quaternary structures.
Why Do Proteins Adsorb to Surfaces?
- Amino acids possess various properties (e.g., acidic, basic, aromatic, hydrophobic, hydrophilic) that influence adsorption.
- Negative charge at the protein surface results in an interaction with the charged surface.
Proteins of the Human Body and Relevance to Biomaterials
- Host proteins readily adsorb to foreign materials.
- Cellular interactions are primarily with the adsorbed protein layer, not the bare material surface.
- Protein adsorption occurs within seconds to minutes after contact.
Blood Composition
- Blood contains a complex mixture of proteins like albumin, IgG, fibrinogen, transferrin, and others, all serving various functions
- Protein concentrations play a major role in influencing protein adsorption and subsequent cell behavior.
- Specific proteins are known to bind either directly or indirectly to cell surfaces, leading to a wide range of cellular responses which vary depending on the particular protein.
Surface-Protein Interactions
- Protein adsorption is usually exothermic (releases heat).
- Increased water liberation and increased protein flexibility from the protein–surface interaction influence protein adsorption.
- Attractive forces including van der Waals forces also influence protein adsorption.
- Electrostatic interactions, hydrophobic interactions, and hydrogen bonding influence protein adsorption.
Colloidal Theory Failure in Protein Adsorption
- The DLVO theory, while capable of describing interactions for colloidal particles, fails to account for protein conformational changes.
Surface and Protein Properties that Determine Adsorption
- Surface properties, including the free energy (hydrophobicity), charge, and topography, directly influence protein adsorption.
- Protein characteristics, including hydrophobicity, charge, molecular weight, and structure, are crucial determinants in protein adsorption.
Protein Adsorption Kinetics
- The adsorption of proteins follows the Langmuir model; factors impacting adsorption include surface binding sites, protein concentration in solution, etc..
Vroman Effect
- Proteins with high mobility and low weight readily adsorb in the initial stage.
- Adsorbed proteins alter the target surface properties, leading to subsequent protein interactions and interactions with other entities.
- The Vroman effect is characterized by a dynamic exchange of proteins over time.
- Different proteins interact with surfaces with varying kinetics and affinities, ultimately altering the surface characteristics.
Protein Corona on Nanoparticles
- Proteins accumulate on nanoparticles to form a protein corona.
- Protein binding interactions result in surface restructuring.
- Protein corona composition and structure are influenced by particle characteristics and solution conditions, including concentration and environmental factors.
Consequences of Protein Adsorption
- Proteins often form a densely packed layer on surfaces over time leading to surface property changes.
- Protein adsorption leads to a higher protein concentration in solution, resulting in a thicker protein film on surfaces than when individual proteins are involved in adsorption.
- Protein adsorption can alter surface properties as well as change how various other proteins function on surfaces and subsequently interact with surrounding entities.
Analytical Techniques for Protein Adsorption
- Numerous techniques (spectroscopy, optical, acoustic) exist for qualitative and quantitative analyses of protein adsorption.
Solution Depletion Methods
- Solution depletion methods allow for the analysis of proteins remaining in the supernatant after adsorption.
- This involves separating the supernatant (fluid containing unadsorbed proteins) from the solid surface after a specific incubation duration
- The technique measures the remaining proteins in the supernatant using various methods, which provide data regarding proteins that have not been adsorbed.
SDS-PAGE
- SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) is a method to separate and identify proteins based on their molecular weights.
- Polypeptide chains interact with SDS and migrate through a gel matrix, thus separating by molecular weight.
Chromatography
- Different chromatographic techniques (ion exchange, gel filtration, affinity) enable separation of proteins in a complex mixture according to different properties, like charge and molecular size.
Mass Spectrometry
- Mass spectrometry involves identifying and quantifying proteins and their constituent peptides based molecular weight.
- Identification and quantitation of proteins in samples based on their mass-to-charge ratios and fragmentations for elucidation of protein identification and interactions with other bioentities.
- Allows to identify proteins based on the precise masses of their constituent peptides.
Proteomics
- Proteomics analyzes the entire protein complement within a system (e.g., blood, cells).
- Various proteomics techniques are used to identify and quantify the complete spectrum of proteins within a system.
- This technique is commonly employed to evaluate changes in protein expression or the protein complement, allowing researchers to understand the overall protein interactions in a system.
Enzyme-Linked Immunosorbent Assay (ELISA)
- ELISA is a specific technique to measure proteins by interacting with antibody-based detection methods
- Specific antibodies are required for accurate quantitative protein quantification.
- The assay works under controlled conditions to allow highly specific interaction between target proteins with antibodies of known specificity.
Fluorescence Microscopy
- Fluorescence microscopy offers techniques for visualization and quantification of proteins, offering detailed spatial protein locations and interactions.
Contact Angle Measurement
- Contact angle measurements determine surface energy characteristics of various materials, by assessing the water contact angle on solid surfaces.
Ellipsometry
- Ellipsometry assesses the thickness and refractive properties of thin films on surfaces, using polarized light to study the protein layer.
Optical Waveguide Lightmode Spectroscopy (OWLS)
- OWLS is an evanescent field technique that determines refractive index changes associated with protein adsorption.
- This allows for real-time monitoring of adsorbed proteins, including detecting proteins in solution, monitoring protein adsorption kinetics without using antibodies, and analyzing protein adsorption without antibody use.
Quartz Crystal Microbalance (QCM)
- QCM is an acoustic technique to measure the mass changes associated with protein adsorption.
- Mass and surface changes associated with protein adsorption can be precisely determined using QCM.
Summary of Analysis Techniques for Proteins and Biomaterials
- Various techniques are available to study protein adsorption.
- These methods can be categorized as labeled versus label-free methods, in situ versus ex situ methods, and various forms of combinatorial techniques.
- Different analytical approaches provide insights into protein adsorption.
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Description
Explore the interactions between biomaterials and body fluids in this quiz. Test your knowledge on protein adsorption, surface properties, and the significance of characterizing proteins at surfaces. Ideal for students studying biomaterials and their applications in medical science.
