Question

Based on the article, Hydrogels for tissue engineering: scaffold design variables and applications:

Why are hydrogels used so often in tissue engineering? Compare and contrast hydrogels with other non-hydrogel based biomaterial.

Answer 1

Hydrogels have become very popular due to some of its properties such as: Softness, high water content, porosity, flexibility, and biocompatibility. Hydrogels can be produced from certain hydrophillic polymers by chemically or physically cross lnking them. Since they resemble the living tissue they are used in various purposes such as contact lenses, hygiene products, wound dressing, drug delivery and in tissue engineering scaffolds.

Biomaterial: Present definition of biomaterial is: a ‘material intended to interface with biological systems to evaluate, treat, augment or replace any tissue, organ or function of the body’.

Three groups of biomaterial are used in tissue engineering:

1. Ceramics: Characterized by high mechanical stiffness, low elasticity and brittle surface. Not used for soft tissue regeneration. Ceramic scaffolds such as hydroxyapatite (HA) and tri-calcium phosphate are used in bone regeneration. HA might seem as ideal as a bone graft substitute but it is difficult to control its degradation rate.

2. Syntheic polymers: Includes the use of polystyrene, poly-l-lactic acid (PLLA), polyglycolic acid (PGA) and poly-dl-lactic-co-glycolic acid (PLGA). Their degradation characteristics have been controlled but they have drawbacks including the risk of rejection due to reduced bioactivity.

3. Natural polymers: Biological materials such as collagen, various proteoglycans, alginate-based substrates and chitosan have all been used in the production of scaffolds for tissue engineering. These scaffolds generally have poor mechanical properties which limits there use.