maintain them while also decreasing wear and extending the
life of the paint. Surfaces that stay free of grease and other
food-sources are much more hygienic and odor-free. Bio-based
additives that catalytically repair polymeric linkages allow for
preparation of self-healing coatings that also reduce repair
and maintenance costs. Bioengineered additives that are naturally hygienic reduce the need for toxic biocides. Naturally-hygienic coatings also provide for the first time a means for
safely reducing the amount of microbial contamination on
interior surfaces with minimal risk of increasing antibiotic
resistance. Other possibilities include antiviral, anti-aller-genic, anti-fouling, deodorizing, desulfurizing, dechlorinating
and pH-adjusting coatings, to name a few.
Several different products are already being developed and
their utility in various coating applications are being investigated. Reactive Surfaces is commercializing bioengineered
additives for use in paint formulations including broad-spectrum antimicrobial peptides, enzymes that benignly break
down phosphate-based chemical warfare agents and pesticides, enzymes that catalyze the synthesis or hydrolysis of
esters for self-repair and keep surfaces free of grease, and
enzymes-peptide combinations that prevent the growth of
algae and fungi on architectural surfaces. 3
Other companies have focused their efforts on one or two
specific products with end-uses in a single targeted market.
MariCal and BioLocus are developing marine anti-fouling
paints, while MiniMed, Inc. is focused on medical device
applications and the Swedish Institute for Food and
Biotechnology (SIFB) and VTT Technical Research Centre of
Finland (VTT) are exploring biomolecules for coatings used in
the food packaging industry. 4
All of these products address a serious unmet need in the
markets they are targeting. In the case of antimicrobial and
antifouling actives, concern over the negative environmental
and safety profiles of many older additives has led to their strict
regulation and/or elimination from use in paints and coatings. 5
The regulatory climate has also reduced corporate investment
in the development of new products, as testing costs can be prohibitive. Antimicrobial peptides, enzymes and biomodulators,
are non-persistent, meet the more stringent regulatory requirements and have been shown to maintain activity over extended
Photo 2: ProteCoat’s effect on algae contamination
periods while presenting no problems with resistance adaptation. Environmentally-benign bio-based additives should significantly reduce the impact of regulatory oversight and allow a
wide-range of new actives to be used by formulators.
ProteCoat from Reactive Surfaces is based on antimicrobial peptide (AMP) technology. 6 AMPs are found in many
different species of microorganisms, plants and animals and
have evolved specifically to protect living things from harmful pathogens, while causing no harm to the host organism.
The additive selectively targets these harmful bacteria,
mold, yeast and fungi and kills them rapidly by disrupting
the cell membrane, avoiding the issue of resistance development, and does so without adverse impact on the host
organism whether human, animal or plant. ProteCoat can
be easily incorporated into various paint formulations
and selectively targets harmful bacteria, mold, yeast and
fungi, killing them rapidly by disrupting the cell membrane while chiefly avoiding the issue of resistance development (see Photo 1 on the previous page).
The effectiveness of AMPs has been demonstrated in-process, in-can and in-film and they have been shown to work
synergistically with traditional biocides, extending the product lifecycle for such traditional biocides. These naturally
occurring amino acid polymers can be readily produced at
commercial scale using existing fermentation technology.
With a substantial library of antimicrobial peptides and
enzymes, Reactive Surfaces designs functional additives
that are tailored to target particular contaminants of interest for any given formulation. As an example, in response to
a request from a formulator, Reactive Surfaces investigated
the activity of AMPs against common algal contaminants in
exterior architectural surfaces and found them to be highly
effective (see Photo 2 below).
Marical and BioLocus have taken different approaches to
developing bioengineered additives designed to prevent
fouling on vessels, oil platforms and other marine surfaces.
Many antifoulant additives in use today are based on heavy
metals like copper, which presents environmental concerns.
Marical has identified calcium sensing receptor (CaSR) proteins that it has incorporated into coatings. 7 These proteins
interfere with the ability of marine invertebrates to settle,
Photos: Reactive Surfaces
Typical algae-contaminated architectural surface (left panel) and a plate of typical algal contaminant (Chlorella vulgaris) showing
effect of 3% ProteCoat in acrylic latex coated paper discs (middle panel) versus control lacking ProteCoat (right panel).
