Bio-responsive polymers hold great promise as delivery vehicles for drugs, peptides and proteins as their chemistry can be tuned to effect a change in physico-chemical properties upon variation of the external conditions, particularly pH, which varies considerably during the delivery process; circulation, cellular uptake and sub-cellular trafficking (pH 7.4 ¿ 4.5). In the light of recent drawbacks in viral gene delivery, there is much hope for cationic polymers as non-viral gene delivery agents, and in this experiment we propose to study environmentally induced conformational changes for a library of amine-containing polymers designed as novel nanomedicine candidates for drug or gene delivery.