posted on 2019-01-31, 20:17authored byMikayla
E. Barry, Emily C. Davidson, Chengcheng Zhang, Anastasia L. Patterson, Beihang Yu, Amanda K. Leonardi, Nilay Duzen, Ketaki Malaviya, Jessica L. Clarke, John A. Finlay, Anthony S. Clare, Zhan Chen, Christopher K. Ober, Rachel A. Segalman
The benefits of incorporating
amphiphilic properties into antifouling
and fouling-release coatings are well-established. The use of sequence-defined
peptides and peptoids in these coatings allows precise control over
the spacing and chemistry of the amphiphilic groups, but amphiphilic
peptoids have generally outperformed analogous peptides for reasons
attributed to differences in backbone structure. The present work
demonstrates that the superior properties of peptoids relative to
peptides are primarily attributable to a lack of hydrogen bond donors
rather than to their secondary structure. A new amphiphilic peptoid
was designed containing functional groups similar to those typically
found on a hydrogen-bonding peptide backbone. This peptoid and a non-hydrogen-bonding
peptoid analogue were incorporated as side chains in PDMS-based polymer
scaffolds. Bioassays with the soft algal fouling organisms Ulva linza and Navicula incerta indicate
that hydrogen bonding largely determines the differences seen between
similar peptide and peptoid species, while sum frequency generation
vibrational spectroscopy suggests that the presence of hydrogen bond
donors enhances interfacial water structuring. This reduced initial U. linza adhesion, but attached algae were more strongly
bound by hydrogen-bonding interactions. Consequently, amphiphilic
peptoid materials lacking hydrogen bond donors are better suited to
resist marine fouling, with enhanced release of U. linza and similar performance against N. incerta relative
to hydrogen-bonding analogues.