MSE 536- SP2025_Cell and Protein Interactions with Biomaterials
MSE 536: Advanced Biomaterials
Course Focus: Cell and Protein Interactions with Biomaterials
Page 1: Overview
Introduction to the intersection of biomaterials and cell/protein interactions.
Page 2: Receptors and Ligands
Receptors: Protein molecules embedded in plasma membranes that bind to signaling molecules (ligands).
Binding leads to cellular/tissue responses.
Receptors are specific to ligands.
Types of Receptors:
Intracellular receptors: Located in cytoplasm or nucleus.
Cell-Surface receptors: Found in plasma membrane, including:
Ion channel-linked receptors
Enzyme-linked receptors
G-protein-coupled receptors (GPCRs)
Page 3: Ion Channel-Linked Receptors
Function: Open channels upon ligand binding to allow ion passage.
Example: Neurons possess ligand-gated channels sensitive to neurotransmitters.
Page 4: Enzyme-Linked Receptors
Structure: Receptors with intracellular domains linked to enzymes.
Function: Some receptors act as enzymes, while others interact with enzymes.
Page 5: G-Protein-Coupled Receptors (GPCRs)
Diverse receptors that bind various ligands.
Example: Olfactory receptors comprise around 800 types in humans for different scent molecules.
Page 6: Cell–Environment Interactions
Key interactions affecting cellular functions:
Focal adhesions: Formed by ECM molecules binding to integrins, impacting cytoskeleton and gene expression.
Secondary messengers: Influence gene expression in response to soluble mediators (e.g., growth factors).
Cellular Functions Affected:
Cell Viability
Proliferation
Differentiation
Protein Synthesis
Page 7: Cell Viability
Survival Factors: Extracellular environment changes (e.g., pH) can induce cell death.
Cell Death Mechanisms:
Necrosis: Caused by membrane permeability, leading to leakage and cellular swelling.
Apoptosis: Programmed cell death with cell shrinkage and consumption of fragments.
Page 8: Cell Proliferation
Proper environment (e.g., space) is vital for cell proliferation.
Cell Types by Proliferation Ability:
Labile cells: Continually replicate (e.g., skin cells).
Permanent cells: Terminally differentiated and do not divide (e.g., neurons).
Stable cells: Specific functions but can proliferate (e.g., liver cells).
Page 9: Cell Cycle Overview
Mitosis (M phase): Cell division process.
Interphase: Preparation phase including:
G1 phase: Cell growth.
S phase: DNA replication.
G2 phase: Protein synthesis.
Non-proliferating cells are in the G0 phase (quiescent).
Page 10: Mitosis Steps
Prophase: Nucleolus dissipates; mitotic spindles form.
Metaphase: Chromosomes align at spindle equator.
Anaphase: Chromosomes are separated.
Telophase: Nuclear envelope re-forms; cytokinesis begins.
Page 11: Cell Differentiation
Stem Cells Categories:
Unipotent: One differentiated cell type.
Multipotent: Several cell types.
Totipotent/Pluripotent: Many cell types, including embryonic stem cells.
Induced pluripotent stem cells (iPSCs): Genetically reprogrammed.
Page 12: Hematopoietic Stem Cell Differentiation
Focus on blood cell production from hematopoietic stem cells.
Page 13: Mesenchymal Stem Cell (MSC) Proliferation
Differentiation Lineages:
Osteogenesis, chondrogenesis, myogenesis, and more from MSCs.
Page 14: Protein Synthesis
Key Roles: Cell communication, ECM creation/remodeling.
Page 15: Collagen Synthesis Process
Steps: Begins with transcription (mRNA formation), followed by translation in the ER, leading to collagen triple helix formation and secretion into ECM.
Page 16: Cell Adhesion and Migration
Impact: ECM interactions affect adhesion and migration across surfaces.
Cellular mechanisms include membrane receptors and cytoskeleton activities.
Page 17: Cell Adhesion Models
DLVO Theory: Interaction model for cells and surfaces based on thermodynamics and potential energy changes.
Page 18: Limitations of DLVO Model
Considerations include steric repulsion and surface topography.
Other models incorporate receptor-ligand interactions as chemical reactions.
Page 19: Cell Spreading and Migration Models
Cell Spreading: Involves integrin interactions and cytoskeletal rearrangements.
Cell Migration Steps:
Membrane extension.
Membrane attachment.
Force generation and movement.
Page 20: Cytotoxicity
Definition: Substances affecting cellular metabolism or protein synthesis negatively.
Cytotoxicity testing is essential for biocompatibility assessments.
Page 21: Direct Contact Assay
Procedure: Test material placed over cultured cells to assess cell viability near the material after exposure.
Page 22: Agar Diffusion Assay
Cells are covered with agar to assess the effects of leachable molecules from biomaterials on viability.
Page 23: Elution (Extract) Assay
Tests cytotoxicity of biomaterials by assessing the effects of soluble leachables on adhered cells over time.
Page 24: Cell Adhesion and Spreading Assays
Quantitative and qualitative methods assess cell adhesion and spreading on biomaterial surfaces.
Page 25: Protein Adsorption on Biomaterial Surface
Biological responses are influenced by the protein layer adsorbed to the biomaterial surface.
Page 26: Gibbs Free Energy (G)
In the context of protein adsorption, considers enthalpy and entropy changes.
Page 27: System Properties Governing Protein Adsorption
Factors affect protein adsorption such as hydrophobicity, charge redistribution, and structural rearrangements.
Page 28: Charge Impact on Protein Adsorption
Similar charges between protein and surface lead to repulsion; opposite charges promote adsorption.
Page 29: Protein Properties Affecting Interactions
Size, charge, hydrophobicity, and stability impact protein adsorption behavior on surfaces.
Isoelectric point: pH equilibrium influencing protein charge for adsorption.
Page 30: Surface Properties Affecting Interactions with Proteins
Includes surface topography, composition, hydrophobicity, and potential, each influencing protein interaction.
Page 31: Amino Acids
Basic protein units with a central carbon, R group variation distinguishes them.
Page 32: pK Value of Amino Acids
Higher pK values indicate more acidic characteristics; related to amino acid behavior in solutions.
Page 33: Functional Role of Amino Acids in Protein Structure
Proline and cysteine play critical roles in determining protein folding structures via their unique properties.
Page 34: Multiple Levels of Protein Structure
Descriptions of primary, secondary, tertiary, and quaternary structures that dictate protein function.
Page 35: Primary Structure of Proteins
Linear order of amino acids via condensation reactions directed by DNA coding.
Page 36: Secondary Structure of Proteins
Localized folding due to hydrogen bonding; includes helices and pleated sheets as common forms.
Page 37: Secondary Structure Variants
Distinguished between ?-pleated sheet conformations, involving hydrogen bonding for stability.
Page 38: Tertiary Structure
3D arrangement driven by side chain interactions; key for protein functionality.
Page 39: Quaternary Structure
Protein complexes formed by multiple polypeptide chains; stability can be affected by environmental conditions.
Page 40: Protein Transport to the Surface
Hydrophobicity, charge interactions, and transport mechanisms influence protein adsorption kinetics.
Page 41: Protein Transport Dynamics
Explains how flow and diffusion dynamics affect the transport of proteins to surfaces in biomaterials.
Page 42: Adsorption Kinetics
High initial rates yield monolayer coverage; subsequent rearrangements and desorption dynamics.
Page 43: Reversibility of Protein Adsorption
Initial reversible binding can precede eventual irreversible adsorption, impacting protein behavior post-adsorption.
Page 44: Desorption and Exchange
Describes dynamic protein exchanges influenced by concentration and surface affinities.
Page 45: Vroman Effect
Highlights how proteins of varying concentrations interact over time based on their adsorption affinities.
Page 46: Assessment Techniques
Techniques for protein identification and quantification relate to surface interactions and adsorbate chemistry.
Page 47: Affinity Chromatography
Utilizes hydrophobic and polar interactions for protein separation and quantification based on adsorption principles.
Page 48: Colorimetric Assay
Quantifies specific proteins based on detectable color changes resulting from enzymatic reactions.
Page 49: Fluorescent Assay
Measures protein presence via fluorescence changes, requiring specific instrumentation for analysis.
Page 50: Fluorescence Microscopy
Example illustrating cell adhesion and spreading on titanium surfaces using fluorescence techniques.
Page 51: Enzyme-Linked Immunosorbent Assay (ELISA)
Technique for identifying specific proteins using antibodies and quantifying via colorimetric changes.
Page 52: Western Blotting
Method for protein separation and identification using gel electrophoresis and specific antibodies.