5 - Scaffolds for Biological Tissue Reconstruction Flashcards
Tissue engineering
Interdisciplinary field that applies the principles of engineering and the life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function
Components of native tissues
- Cells
- ECM
- Vessels (nutrients, O2 supply)
Tissue engineering paradigm
- Cell isolation
- Cell expansion
- 3D scaffold (mechanical stimulus, growth factors, cells)
- Graft transplantation
Hurdles for tissue engineering success
- Technical
- Commercial
- Regulatory
- Ethical
Autologous cells
From patient
Allogeneic cells
From another human
Xenogenic cells
From a different species
Biomaterials
- Used to develop scaffolds or templates for cells to organize and restore structure and function to damaged or dysfunctional tissues.
- Guidance can be achieved through biophysical and biochemical cues that direct cell behaviour, morphology, adhesion, and motility
Biological factors that influence the function and behaviour of cells in the scaffold
- Hormones
- Cytokines
- Growth factors
- Extracellular matrix molecules
- Cell surface molecules
- Nucleic acids
How does a cell interact with its environment
- Chemical signals
- Mechanical signals
Mechanotransduction
Mechanical signals are converted into signal transduction pathways.
Mediators of mechanotransduction
- Surface processes
- Membranes (ion channels)
- Cytoskeleton (microfilaments)
- ECM (collagen)
- Cell ECM adhesions (integrins)
- Nuclei (gene expression)
- Cell-cell adhesions (gap junctions)
What regulates stem cell lineage commitment
Cell shape, Cytoskeletal tension and RhoA
Two categories of tissue engineering approaches
- Transplantation of in vitro grown tissues
- Promotion of tissue regeneration in situ
Transplantation of in vitro grown tissues
Biomaterial/scaffold + cells transplanted leading to tissue regeneration
Promotion of tissue regeneration in situ
Biomaterial/scaffold transplanted, leading to recruitment and reorganisation of host cells and eventually tissue regeneration
Materials in tissue engineering / desirable properties of biomaterials
- Adequate mechanical properties
- Biocompatible
- Biodegradable
- Porous structure
- Promote tissue regeneration/cell attachment