Biological Adhesives

WORKING GROUPS

Working Groups Diagram

To address the objectives of the Action, four working groups (WG) have been set up that draw on the complementary expertise and facilities of their members :

  • WG1: Chemical characterization and synthesis of adhesives
  • WG2: Structural characterization of natural and synthetic adhesives
  • WG3: Mechanical testing and theory
  • WG4: Fabrication of bio-inspired adhesives and their evaluation

To reach a maximal trans-disciplinary knowledge exchange, the scientific purposes of the different WG intentionally overlap, and transversal interactions are encouraged. Each group include specialists from various disciplines, and members can participate in several WG in order to enhance the information exchange in different directions. Moreover, partners from industry are encouraged to participate in the WG to recognize opportunities for technology transfer and commercial applications.

Working group 1

Chemical characterization and synthesis of adhesives
 

Working group leader: Prof. Markus Linder (FI)
Working group co-leader: Dr. Marisa Almeida (PT)
 

The aim of this group is to isolate and characterize biological adhesives at both the biochemical and/or physico-chemical levels.

 

The central tenet is to identify key features of natural adhesives. Secreted adhesives usually consist of complex blend of different biopolymers. These macromolecules can be purified either from the adhesive directly or from the organisms producing them, fractionated into their different components which then can be characterized by biochemical analyses. Proteins are identified by mass spectrometry-based proteomics. This same method is used to characterize their post-translational modifications which are usually fundamental to the function of biological adhesives. Molecular techniques, including DNA and RNA extraction, PCR, cloning and sequencing, are used to obtain the primary sequence of the adhesive proteins. Synthetic adhesives are produced as recombinant proteins through expression techniques or as biopolymer mimics through polymer chemistry. The analysis of the adsorption of the adhesive biopolymers to the substratum surface are characterized by a range of tools such as infrared ATR and Raman spectroscopies, atomic force microscopy (AFM), quartz crystal microbalance (QCM), imaging surface plasmon resonance (iSPR) and imaging ellipsometry.

Working group 2

Structural characterization of natural and synthetic adhesives

 

Working group leader: Dr. Nicholas Aldred (UK)
Working group co-leader: Dr. Mattias Berglin (SE)

 

This group focuses on the complex hierarchical structures (from micro- to nanometric scales) of adhesives that is as important as the chemical composition for their function.

 

Broad systematic functional comparative studies on biological systems are planned using various modern microscopic techniques, in order to extract essential structural principles behind their functions. Natural and synthetic adhesives are investigated to gain understanding of their organization. Understanding adhesion and the interaction of adhesives with surfaces and interfaces requires an understanding of surface properties before, during and after spreading and/or curing of any adhesive. To this end, it is essential that surfaces used for testing are controlled and well-characterized. Surface analytical tools (see WG 1) must therefore be applied for the characterization of surface composition, structure and dynamics.

Working group 3

Mechanical testing and theory

 

Working group leader: Prof. Stanislav Gorb (DE)
Working group co-leader: Dr. Philippe Leclere (BE)

 

To understand the detailed function of biological adhesives, it is essential to characterize their adhesive and frictional performance, as well as their material properties and tribological interactions under standardised conditions.

 

Biological attachment devices are typically hybrid systems consisting of complex mechanical units that are integrated with an adhesive system. The mechanical testing has to be performed at several levels, from the evaluation of the nanomechanical properties of the constituent biomolecules of the natural adhesives, to in vivo force measurements on microscopic and macroscopic whole organisms. To determine how some organisms control adhesive forces dynamically, their movements are also investigated. To allow comparisons between different systems (wet and dry, natural and synthetic), adhesion and friction forces are measured under controlled conditions, in combination with optical techniques to monitor the adhesive contact. Attachment performance has to be evaluated while varying a number of relevant experimental conditions such as surface energy and roughness, pulling and sliding velocity, pull-off or peeling direction, contact time, submersion and hydration. The experimental data on the mechanical performance of adhesives are used to test theoretical models of adhesion and friction. The models will help to identify new principles where natural systems show a different behaviour. Moreover, simplified models will be the starting point for the design of synthesised adhesive systems. These will provide excellent physical models that can be used to test the predictions from theory.

Working group 4

Fabrication of biomimetic adhesives and their evaluation
 

Working group leader: Dr. Aranzazu Del Campo (DE)
Working group co-leader: Dr. Willi Schwotzer (CH)
 

This group focuses on the engineering of new biomimetic adhesives systems with the tailoring of the surface properties and control of those parameters that the theoretical models and the experiments have identified to be crucial in the adhesion process.

 

The fabrication of patterned adhesives requires the synthesis of surfaces with a controlled roughness or with nanostructured features such as thin pillars, bumps, and domes regularly spaced to form a matrix. Also, innovative designs will be tested and evaluated by coupling key features from different biological models (e.g. micro-fabricated surfaces coated with thin polymer films).
 

The bio-inspired materials generated by this WG will meet the current scientific and technological challenge of developing a new generation of adhesives, in particular for the development of reversible pressure sensitive adhesives or of adhesives working in a fluid environment. The different biomimetic adhesives produced will be tested in specific applications in collaboration with industrial partners.

 

NEWS

2016-11-3

Tue, 2016-11-01

COST CA15216 ENBA

A new COST Action dedicated to biological and biomimetic adhesives is starting on November 1st 2016. The Action is entitled “European Network...

2015-2-2

Fri, 2015-02-06

Interface Focus

The final publication of our Action TD0906 has just appeared as the latest theme issue of the Royal Society journal, Interface Focus: http://rsfs....