biomaterials final 2.0

PEG

Chemical modification of proteins and other bioactive molecules with polyethylene glycol (PEG) or its derivatives (PM) can be used to tailor molecular properties to particular applications, eliminating disadvantageous properties or conferring new molecular functions.

Proteoglycans such as aggrecan in cartilage tissue is another major ECM component. Based on the general compositional and structural features of proteoglycans. What cell organelles are involved in the biosynthesis of proteoglycans?

Protein part from ribosomes, then translocated into the lumen of the rough endoplasmic reticulum; glycosylation of the proteoglycan occurs in the Golgi apparatus in multiple enzymatic steps.

Vasculargenesis

Two blood vessels fuse to form right and lift atria and ventricles, septation occurs between sections

angiogenesis formation

begins when when oxygen sensing mechanisms detect a level of hypoxia that demands new blood vessel formation to allow for proper metabolic function. Myocytes, hepatocytes, neurons, astrocytes, etc. will respond to hypoxia by secreting key growth factor called vascular endothelial growth factor

bio fabrication of organoids

bioassembly, 3D bioprinting, organs on a chip.

matrix patterning for organoid morphogenesis.

cell-adhesive ligands, material mechanics, material degradation.

material systems for organoids

decellularized tissues, natural biopolymers (collagen, lamanin, alginate...), protein engineered materials, synthetic polymers (PEG)

vascular formation

difference between hemangioblasts from mesodermal cells. Then gives rise to angioblasts and endothelial cells. angioblasts interact with growth factors in the ECM and form blood clusters of angioblasts and create endothelial cells.

why does angiogenesis occur?

helps blood reach newly formed wounds to heal them. It can also perform vital tasks in the body like help with hypoxia.

angiogenesis

is the physiological process by which new blood vessels form from preexisting blood vessels through sprouting and and splitting from the vascularization

Organoids

miniaturized and simplified version of an organ produced in vitro in three dimensions that shows realistic micro-anatomy

current materials for vascularization

native: fibrin, collagen, matrigel Synthetic: PEG, gelatin, HA

organoid cell sources

primary tissue cells, human adult stem cells, pluripotent stem cells.

Engineering functional vascular network that allows

rapid integration with host vasculature and promotes faster perfusion after implantation

limitations with organoids

standardization of growth methods, physiological accuracy of tissue architecture, lack of vascular and neural inputs, lack of increased interstitial pressure.

which of the following can trigger angiogenesis

tissue injury, hypoxia, tumor growth and metastasis.

organoids can be generated from

tissue samples for a variety of organs.

benefits of organoids

Advanced tissue culture system with organ-level of complexity Capacity to differentiate into different cell types, expansion Better modeling system than animal testing Maintain genomic stability High throughput screening

Among all major types of glycosaminoglycans, which one is least charged and which one has the highest charge density? State your reasoning.

HA least charged, no sulfate; heparin highest charge density, highest sulfates

all main types of GAGs

HA; heparin/heparan sulfate; keratin sulfate; chondroitin sulfate

HA

Hyaluronan (HA) is a linear polysaccharide with disaccharide repeats of D-glucuronic acid and N-acetyl-D-glucosamine. It is evolutionary conserved and abundantly expressed in the extracellular matrix (ECM), on the cell surface and even inside cells

main functions of glycosaminoglycans

Hydration, swelling, creates pressure to resist compression, growth factor binding, anticoagulant

Glycosaminoglycans (GAGs)

Long polysaccharides composed of amino sugars and uronic acid (disaccharides) Regulate water and electrolyte balance of tissues

hypoxia

Low oxygen saturation of the body, not enough oxygen in the blood

dynamic organoid niches

Native ECMs are highly dynamic, stress-relaxing matrices - properties that can be engineered in chemically defined materials

difference between angiogenesis and Vasculargenesis

Vasculogenesis gives rise to the heart and the first primitive vascular plexus inside the embryo and in its surrounding membranes, as the yolk sac circulation. Angiogenesis is responsible for the remodeling and expansion of this network. While vasculogenesis refers to in situ differentiation and growth of blood vessels from mesodermal derived hemangioblasts, angiogenesis comprises two different mechanisms: endothelial sprouting and intussusceptive microvascular growth (IMG)

proteoglycans

a glycoprotein consisting of a small core protein with many carbohydrate chains attached, found in the extracellular matrix of animal cells. They can also serve as lubricants, by creating a hydrating gel that helps withstand high pressure. The protein component of proteoglycans is synthesized by ribosomes and translocated into the lumen of the rough endoplasmic reticulum