Page 88 - Advances in Textile Biotechnology

Smart materials containing enzymes or enzyme substrates 67

effector units releasing the effector unit after selective trigger activation via
spontaneous chemical breakdown (Tranoy-Opalinski et al., 2008).

A broad field of application is the linking of active agents on various
surfaces such as wound dressings in medicine. A controlled-release system
of antibiotics is described by Suzuki et al. (1997) to provide adequate local
antibiotic concentration against an infection. A delivery system was created
using a polyvinylalcohol (PVA) hydrogel carrying an enzymatically degra-
dable peptide linker for binding gentamicin. In vitro experiments with this
wound dressing showed that proteases from infected wounds cleaved the
linker and gentamicin was released. The exudates from non-infected wounds
had no hydrolytic activity towards the linker. The same group described a
thrombin-sensitive peptide linker system using the elevation of thrombin-
like activity in infected wound exudates as the key component of this
system (Tanihara et al., 1998).

3.4 Conclusion and future trends
In summary, the high specificity of enzymes can be exploited for the design

of smart materials in two ways. On the one hand, enzymes can impart novel
sophisticated functionalities to materials ranging from antimicrobial effects
to self-cleaning or self-detoxifying properties. On the other hand, enzymes
can be used as triggers to impart bioresponsive properties to materials

containing specific elements susceptible to modification by these biocata-

lysts. Both concepts have already been exploited for the construction of
smart fabrics. An instructive good example are wound dressings containing
enzymes to impart haemostatic or antibacterial properties or containing
antibiotics released upon contact with enzymes from infected wound as
triggers. As a result of advances in the discovery of novel enzymes and in
genetic engineering, highly stable biocatalysts with increased effi ciency for
the target substrates are currently becoming available. Together with novel
fabrication technologies this should lead to implementation of smart mate-
rials containing enzymes or enzyme substrates described here in various
industrial sectors. Also, environmental legislation will favour materials that
lead to a saving of resources by use of controlled release and biocatalytic

reactions. Finally, customer/society benefits such as reduced resistances to
antibiotics resulting from the controlled application of drugs or hygienic

benefits owing to self-cleaning or antimicrobial properties will be a driver
to bring these smart materials to the markets.

3.5 Acknowledgements
This work was financed by the SFG, the FFG, the city of Graz and the

province of Styria within the MacroFun project and supported by the Euro-
pean COST868 program.

© Woodhead Publishing Limited, 2010