attach or metamorphose on marine surfaces.
BioLocus, on the other hand, has identified enzymes that
degrade the glue that barnacles use to attach themselves to
surfaces. 8 Coatings containing the BioLocus additive are
undergoing both static and in-motion tests. There have, in fact,
been numerous studies of enzymes for antifouling applications
and a review of this work was published in 2007.9
A third company, I-Tech, is developing a small molecule
anti-fouling agent that, while not a biological macromolecule
itself, has a biological mode of action and is thus of interest. 10
Medetomidine (catemine 1) binds to certain protein receptors
on the cell surface of the fouling organisms, creating a specific response. In this case, the result is increased motility of the
larvae, which prevents them from being able to explore the
surface and ultimately prohibits attachment.
Enzymes are also being investigated in coatings designed
for food packaging applications. Glucoside oxidase (GOx) has
been investigated by both the SIFB and VTT. SIFB has prepared carboxylated styrene acrylate latex coatings with GOx
that have been shown to be effective as oxygen scavengers in
food packaging. 11 The enzyme can be immobilized on the surface of the film as well as entrapped within the polymer
matrix. VTT, meanwhile, immobilized GOx onto plasma-acti-vated biooriented polypropylene films. 12
Enzymes have also been a target of research at Reactive
Surfaces. OPDTox and DeGreez are enzyme-based additives designed for use in paints. Each presents a new functionality for coatings not previously available.
OPDTox contains organophosphorous hydrolases (OPH)
that cleave specific bonds in the phosphoryl centers of
organophosphorous compounds, which include common insecticides (malathion, parathion and coumaphos) and chemical
warfare agents (soman, sarin and VX). 13 The byproducts of the
reaction are not toxic, and Reactive Surfaces can tailor the
enzymes for specific applications. This method of decontamination is much more attractive than current processes, which
typically involve the use of harsh chemicals or foams, high
heat or caustic oxides. Preliminary testing of OPDTox-con-taining CARC-painted (Chemical Agent Resistant Coating)
panels against actual nerve agents delivered as neat droplets
to painted panel surfaces by a working group of NATO member countries has shown encouraging results. 14
DeGreez also provides a way for reducing the use of chem-
icals. When added to paint formulations, the lipase enzyme
degreases surfaces exposed to natural greases and oils.
Because of the catalytic nature of the enzyme, it will per-
form continuously over extended periods of time. Not only is
the need for cleaning chemicals reduced, but odor and
microbe contamination concerns are eliminated.
BRINGING VALUE TO THE MARKET
These products are just the tip of the functional additive iceberg. Ongoing R&D efforts at Reactive Surfaces and other
companies as well as in a number of academic labs are leading to the introduction of many more bioengineered additives for adding functionality to paints and coatings.
Combinations of bio-based additives each delivering differing functionalities, are providing additional novel solutions
to real-world coatings problems.
A critical part of these research activities involves preparation of additives that are suitable for incorporation into
paints and coatings. Specialized technologies for stabilization
and distribution of the bioactive materials into a formulation
ensure that the peptides, enzymes or other components perform at the desired level throughout the lifecycle of the coating, including during production, while in storage in the can
and of course in the applied film. Reactive Surfaces has established a team of scientists including formulation experts from
the University of Southern Mississippi and leading microbiologists and genetic engineers from Texas A&M University
and the University of Georgia to focus on these issues.
When developing new products, this group first considers
the target application for the functional coating and the specific ways in which a bioengineered additive can add unique
value. The conditions under which the additive must perform
(temperature, humidity, weather, microbes, chemicals, UV
radiation, etc.), the possible application methods for the coating, compatibility with other ingredients, and the means of
incorporating the additive all have to be taken in to consideration. The advanced tools of biotechnology make it possible to
create additives with specific capabilities and physical characteristics most suitable for the production and application conditions required for a certain end use application. In many
cases, both the functionality and other properties of the additive can be adjusted to meet the specific needs of individual
customers or market segment.
This easy functional “dial-ability” increases the value add
that bioengineered materials can contribute to paints and
coatings, as does the vast array of possible biomolecules and
Photo 3: DeGreez 72-hour decontamination
Photos: Reactive Surfaces
The first image at left shows an uncontaminated surface; image two shows a surface heavily contaminated with vegetable oil; the
third image shows the effect of DeGreez after 72-hour decontamination.
