What are 3 sources of cells?
Autologous - cells derived fromt he same body as the patient
Allogenic - cells derived from another body and donated to the patient
Xenogenic - cells derived from another species
What are scaffolds?
A template for cells to initially adhere and aid further tissue development
Can be natural (ie. collagen or fibrin) or synthetic (ie. polymers such as polylactic acid)
Should be biocompatible and biodegradable (degradable at same rate as ECM is produced by cells)
How is a bioreactor used in tissue engineering?
Provides the environment required that can be controlled precisely outside of the body
Can only support growth of cells in culture to form a thin sheet of tissue (4-7 layers thick)
Describe the process of skin transplantation in burn victims
Slice off epidermis along with a thin slice of dermis from small samples of the patient's healthy skin
Dissociate into single cells and put into culture flasks
Allow cells to grow to confluency on surface of flask then passage once or twice (2cm2 of cells can be expanded 10,000 times)
Transfer the intact monolayer on sheets of gauze and transplant onto burn
What are some problems with transplanting skin?
The underlying dermis grown invitro does not have swear glands or hair follicles and will not be capable of wound contraction
How can the potential problems of skin transplantation be overcome?
1. Creating a dermal equivalent surface - dissociate fibroblasts from a tissue donor (normally neonatal foreskin tissue)
Fibroblasts are mixed with collagen in culture medium and pour into moulds which causes the collagen to condense into a gel-like matrix
Fibroblasts will attach to the collagen forming a matrix tissue
2. Creating epidermal-equivalent surface - Keratinocytes are layerd onto the dermal-equivalent cell surface also derived from neonatal foreskin tissue
Keratinocytes will grow to form multiple layers. At which point the artificial skin is exposed to air to form the dead layer of cells
Graft to patient
What sorts of cells is the bladder comprised of?
Bladder consists of:
uroepithelial cells (makes up the mucosa)
smooth muscle cells (surrounds the outside of the bladder cells)
fibroblasts (synthesizes the connective tissues between the epithelial cells and smooth muscle cells)
How long did it take to culture uroepithelial ands smooth muscle cells in bladder engineering?
What are some key processes in heart engineering?
Decellularization of cadaver hearts from a rate (removal of cells using SDS, PEG or Triton X-100)
The heart matrix (collagen I & III and fibronectin) is seede dwith neonatal cardiac cells
The scaffold is mounted in bioreactor and provided with medium flow that simulated the pressure of the cardiac cycle; then reseeded with endothelial cells to line the coronary vessels and te enocardial surface
the construct initiated contractions after 8 days of culture