Page 45 - Handbook of Adhesion Promoters

38 Mechanisms of Adhesion

values obtained for the laminate and the adhesive as a consequence of the reduction in the
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water flux produced by the presence of the reinforcement fibers.
2.12 MICROBIOLOGICAL AND BIOLOGICAL ADHESION

Many products are affected by microbiological and biological colonization which is,
therefore, in the center of attention is many fields, such as coatings, pharmaceutical, med-
ical, dental, electronics, water transportation, and many other. Surface colonization by the
biological organisms is, thus, essential for the developments in these fields as well as
experience from analysis of adhesion by biological organisms may be useful inspiration in
other areas of interest.
Reviews and book chapters are available on the subject of adhesion of microbiologi-
cal and biological species to different surfaces which can be additionally consulted. 77-80
Colonization in biological systems (e.g., colonization of mucosal surfaces of the gen-
itourinary, gastrointestinal or respiratory tracts leading to infection and development of
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disease) are much more complex than the described above mechanisms of adhesion. The
first interaction of bacteria with host surfaces relies on non-specific interactions, involving
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hydrophobicity, charge, or other surface properties (similar to non-living things). This
interaction provides the initial contact, which must be followed by specific receptor inter-
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actions to allow colonization to proceed. There are three main types of adhesin-receptor
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interactions. In the majority of bacterial pathogens, lectin-carbohydrate recognition is
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the main type. Many pathogens express surface lectins that serve as adhesins that bind
the bacteria to carbohydrate moieties of cell surface glycoconjugates, such as glycopro-
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teins or glycolipids. Other types require protein-protein interaction or hydrophobin-pro-
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tein interaction. Several strategies have been developed to prevent adhesion of
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microorganisms to human organisms. Some of the strategies are listed in Figure 2.43.
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The term biofilm was coined in 1975 to describe bacterial communities. The for-
mation of biofilm protects the resident bacteria from the impact of the immune response

Figure 2.43. Strategies for anti-adhesion therapy. Bacterial attachment can be inhibited by interfering with
adhesin biosynthesis (A), adhesin assembly (B), or host receptor assembly (C). Binding can be inhibited by com-
petitive replacement of the adhesin from the host (D) or of the host receptor from the adhesin (E) using soluble
molecules or by using designer microbes (F). Antibodies against bacterial adhesins can block surface epitopes
required for binding (G). [Adapted, by permission, from Krachler, AM; Orth, K, Virulence, 4, 284-94, 2013.]