This same strategy was adopted in the activation of polyester
fibres for covalent OpdA immobilization. The most effective
polyamine that has been used is undiluted EDA. However, 99%
EDA is volatile and corrosive. We explored whether EDA could
be replaced by a less volatile diamine (e.g. diethylenetriamine), or
whether diluted EDA (e.g. 50%) could be used at elevated temperatures
(40 ◦C, 60 ◦C or 80 ◦C) in the activation. However, none of these
conditions proved to be very successful (data not shown). The conditions
used in a previous study [20], i.e. treating the fibre with 99%
EDA for 2 h at room temperature, was found to be optimal and was
therefore employed in all subsequent work.