1B Cell Adhesion Part 1

Tissue Engineering

Introduction and Cell Adhesion

  • Overview of the topic presented at Gilman Hall, Johns Hopkins University, Whiting School of Engineering.

Cell Adhesion

  • Importance of cell adhesion in the context of tissue engineering.

Hierarchical Complexity of Cells

  • Human body contains between 50 and 75 trillion cells.

  • Several hundred distinct cell types arise from a single fertilized cell.

Modular Design: Hierarchy in Tissue Engineering

  • Cells → Tissues → Organs structure:

    • Stem Cells: Undifferentiated cells that can develop into various cell types.

    • Progenitor Cells: Partially differentiated cells that can further differentiate.

    • Differentiated Cells: Specialized cells such as:

      • Endothelial cells (part of blood vessels)

      • Muscle cells

      • Fibroblasts

      • Bone cells

    • Example: Blood vessels can consist of various types of cells working together.

Importance of Tissue Structure

  • Tissues are collections of cells.

  • Spatial context is crucial for cellular function.

  • Mechanisms in place for creating and maintaining tissue structure.

Rules Governing Cell-Cell Interactions

  • Inquiry into what occurs if cells from different tissues are mixed.

Thermodynamic Equilibrium in Cells

  • Classic experiment with epidermal and neural plate cells isolated from tissues.

  • Cells were pseudo-colored for visibility and randomly mixed.

  • Resulted in aggregation into spheroids.

  • Predictable organization: epidermal cells form a shell around neural cells.

Impact of Thermodynamic Forces on Cell Adhesion

  • Cells experience attractive and repulsive forces when approaching a surface.

  • The balance of these forces determines cell adhesion at surface distances of 100 - 300 nm.

Measuring Cell Adhesion

  • Semi-quantitative methods for measuring cell attachment to substrates.

  • Challenges in standardization: measuring shear force during washing presents difficulties.

Quantitative Measures of Cell Adhesion

  • Discussion on a system used to determine adhesion forces:

    • Understanding parameters such as volumetric flow rate (Q), channel dimensions, and the relationship of these to adhesion forces.

  • Formulae and concepts utilized to quantify adhesion between cells and substrates.

Copyright Note

  • © The Johns Hopkins University 2021, All Rights Reserved.