Enter into the ‘Sticky’ World of Bioadhesion!

TAGS:  Natural-based Adhesives    

Nature produces a wide variety of glues. From mucus of snails to the bonding principle of orchids or the tree frogs, the scope of biological adhesives is not limited to only the gecko!

Many living creatures rely on concept of adhesion to survive in the world.

Such as:

• Frogs use adhesion to climb plants 
• Barnacles make use of this property to attach to the surface
• Salamanders use glue as a defense against predators
• While spiders/velvet worms use it as a means to attack
• And many more… 

And, these creatures are now providing answers to meet technical challenges in applications ranging from underwater to bioengineering as well as industrial settings! Natural and bioinspired glues are also being considered for medical applications such as surgical adhesives and diabetes treatments.

However, even simple biological adhesives may require years of research to understand sufficiently to allow for mimicry.

COST CA 15216 - The European Network of Bioadhesion is one such organization where a group of scientists, engineers, physicians, SMEs, applied research organizations… is working to understand the basic principles governing biological adhesion by gathering knowledge about these materials:

• Composition
• Structural design and
• Interactions with surfaces

The World of Bioadhesion

In the event held last year, Scientific Representative, Janek von Byern, in his presentation gave us quite a list, which he mentioned is just the tip of the iceberg. These included:

• Bacteria
• Algae
• Kelp
• Cephalopod (one of the oldest animals)
• Mussel
• Barnacle
• Sea cucumber
• Sea star
• Snails
• Sandcastle worm
• Jellyfish
• Ticks
• Salamander
• Frog… and 100s more…

Biological Adhesives: Similarities & Differences

Janek spoke of 3 very interesting examples in particular. Let’s take a look!

Organism	Example Type	Bond Strength	Advantages	Disadvantages
Mussels	Substrate bonding	< 2.28 MPa	Glue composition known - L-DOPA  Stable & firm bonding L-DOPA combinable with chemicals Bonding ( > min.) on each surface type Application - wound healing & cosmetics in pipeline	Bonding only on wet surfaces Permanent bont High production costs  S. Korean patent on L-DOPA production
Glow Worm	Prey capture	< 0.005 MPa	Glue stable over weeks, bonding at contact only  Bonding within seconds  Bonding on any dry surface  Few components only (urea…)  Urea	Bonding with initial high amount of water (> 80% rH)  Low bond strength  Glue not characterized yet - 5-6 years more needed
Salamander	Defense	> 1.7 MPa	Bonding within milliseconds  Bonding on most surfaces  High bond strength  Multi-component system  Automatic water loss after curing	Protein-based glue  Artificial production unclear No bonding on hydrophobic surfaces  Glue not characterized - 3-4 years more needed

Advantages & Disadvantages of Biological Adhesives



And the best part is? They are all bio-degradable and non-toxic (except of course when nature intends them to be poisonous!)

  » Stay Connected and Check Out the developments in Bio-inspired Adhesives here!