Barnacle Balanus amphitrite Adheres by a Stepwise Cementing
Process
Daniel
K. Burden
Daniel E. Barlow
Christopher M. Spillmann
Beatriz Orihuela
Daniel Rittschof
R. K. Everett
Kathryn J. Wahl
10.1021/la301695m.s001
https://acs.figshare.com/articles/media/Barnacle_Balanus_amphitrite_Adheres_by_a_Stepwise_Cementing_Process/2486248
Barnacles adhere permanently to surfaces by secreting
and curing
a thin interfacial adhesive underwater. Here, we show that the acorn
barnacle Balanus amphitrite adheres
by a two-step fluid secretion process, both contributing to adhesion.
We found that, as barnacles grow, the first barnacle cement secretion
(BCS1) is released at the periphery of the expanding base plate. Subsequently,
a second, autofluorescent fluid (BCS2) is released. We show that secretion
of BCS2 into the interface results, on average, in a 2-fold increase
in adhesive strength over adhesion by BCS1 alone. The two secretions
are distinguishable both spatially and temporally, and differ in morphology,
protein conformation, and chemical functionality. The short time window
for BCS2 secretion relative to the overall area increase demonstrates
that it has a disproportionate, surprisingly powerful, impact on adhesion.
The dramatic change in adhesion occurs without measurable changes
in interface thickness and total protein content. A fracture mechanics
analysis suggests the interfacial material’s modulus or work
of adhesion, or both, were substantially increased after BCS2 secretion.
Addition of BCS2 into the interface generates highly networked amyloid-like
fibrils and enhanced phenolic content. Both intertwined fibers and
phenolic chemistries may contribute to mechanical stability of the
interface through physically or chemically anchoring interface proteins
to the substrate and intermolecular interactions. Our experiments
point to the need to reexamine the role of phenolic components in
barnacle adhesion, long discounted despite their prevalence in structural
membranes of arthropods and crustaceans, as they may contribute to
chemical processes that strengthen adhesion through intermolecular
cross-linking.
2016-02-20 11:30:47
BCS 2
Barnacle Balanus amphitrite Adheres
adhesion
phenolic
interface
barnacle cement secretion
acorn barnacle Balanus amphitrite
fracture mechanics analysis
fluid secretion process
protein
BCS 2 secretion