BE 201 Flashcards
what generates all types of the cells in the body
Totipotent cells
what can tissue engineering do
cell expansion and manipulation
cell seeding and extracellular matrix expression
full incorporation into host
cell sourcing
diseases that could be treated with tissue engineering
cancer, tobacco smoker lungs, polycystic kidney,
a graft of tissue from one point to another of the same individual’s body
Autograft
a graft of tissue from one individual to another individual of the same species who is not an identical twin
Allograft
a tissue graft transplant from a donor of a different species from the recipient
xenograft
limitation of these current therapies
Lack of suitable harvest sites
Tissue rejection, transmission of disease, ethics
materials subject to fracture, fatigue, toxicity, and wear
Graft
tissue from one site place on another site,
cost, likelihood of rejection, ethics
examples; bone , skin, lymphocytes, organs
cell-based
cellular therapy,seeks to repair damaged and diseased tissues by transplanting healthy new cells to the affected site
scaffold-guided
seeding a porous biodegradable scaffold with donor cells and or growth factors, then culturing and implanting the scaffold to induce and direct the growth of the new tissue. The goal is for the cells to attach to the scaffold, replicate and ultimately grow into healthy, functioning tissue as the scaffold degrades
Bioactive molecule-based
utilizes regulatory molecules, also known as growth factor, to induce and direct cell growth and differentiation
what is true about ECM
A. ECM is collected of extracellular molecules that are secreted by the cells themselves.
B. It provides physical or structural support to the cells
C. It provides biochemical molecules to the cells
ECM function
structural support, biochemical support, cell adhesion, cell to cell communication an differentiation
proteoglycans
glycosaminoglycans + carbohydrate attached to proteins
- charged
-trap water molecules to keep the ECM and cells hydrated
- trap molecules that are essential for normal cell activities
collagen
-most abundant protein in the ECM
-human body accounts for 90% of bone matrix protein content
3D scaffolds
-provide mechanical stability
-deliver therapeutic agents
-facilitate processes critical in tissue repair
3D scaffolds
natural materials
-collagen gel, alginate, agarose,decellularized tissue
synthetic materials
-freeze drying, porogen leaching, electrospinning, 3D printing
3D Scaffold
Non-toxic
biocompatible or even bioactive
biodegradable - depends
mechanical properties
surface properties
porosity, pore size
Pore interconnectivity
internal architecture
active or static
porosity
Vv/Vt
Vv= volume of void-space
Vt= total or bulk volume of the material
grafts vs implants
Grafts contain cells
Autograft
Allograft
Implants do Not contain cells
Bone Autografts
Harvested from a donor site in a patient
osteoconduction
the property by which a graft supports the attachment of new osteoblasts and osteoprogenitor cells
osteoinduction
the induction of osteoprogenitor cells to differentiate down an osteoblast lineage
Bond Allografts
-Eliminates the need for a second surgical site
-not necessarily immuno-privileged
-
Bone TE
-soft tissues heal exclusively by scar tissue formation
-The smallest size intraosseous wound in a particular bone and species of animal that will not heal spontaneously during the lifetime of the animal
Design Criteria
Non-toxic
osteoconductive , osteoinductive
biodegradable
non- invasive
size of the problem
American with arthritis second to heart disease
cause of disability among american over age 15
Articular cartilage
- Avascular
-little ability of self-healing
-tissue has solid ECM component and fluid phase
-chondrocytes:specialized phenotype, which is lost with expansion in monolayer culture
-low friction, weight-bearing, transmit high stress associated with joint motion
chondrocytes
limited supply
aged chondrocytes are less able to form functional constructs in agarose culture
must be isolated from the joint tissue itself
MSC chondrogenesis
high density culture, pellet culture
purpose of skin
-barrier to foreign pathogens
-regulating body temperature
- preventing dehydration
-providing sensation
allografts as a temporary fix
usually from cadavers
always rejected
alternatives
cultured autologous keratinocytes or bioengineering skin substitutes
-Bilayer structure
-Permeable to moisture and not to water
-Lower layer that acts as skin regeneration
template
Ideal properties of bioengineered skin
so far is not available
. Non-Toxic, non immunogenic
. No risk of disease transmission
· Biodegradable
Similar physical and Mechanical Properties to real skin
Able to support reconstruction of normal tissue
. Provide pain relief
. Prevent fluid and heat loss and infection
· Cost-Effective, available, good shelf life
integra Dermal regeneration template
no living components
two layers - matrix of collagen and GAG, and a flexible silicon sheet
purpose : protective covering and scaffold for regeneration
Dermagraft
cryopreserved human fibroblast-derived dermal substitute for advanced treatment of diabetic foot and leg ulcers
Spray on skin
patented skin culturing treatment for burns victims, developed by plastic surgeon
still a long way to go
lacks hair follicles
sweat glands
dendritic cells
