Temperature and pH responsive polymers react to environmental changes.

2004 SEP 18 - (NewsRx.com & NewsRx.net) -- Temperature and pH responsive polymers react to environmental changes.

According to recent research published in the Journal of Controlled Release, "poly(N-isopropylacrylamide) (PNIPAm) co-polymers responsive to temperature and pH were prepared with side chain chemistries in order to exhibit phase transitions under physiologically relevant conditions."

"Fluorescence spectroscopy, gel retardation assays, dynamic light scattering and atomic force microscopy were used to characterize the binding of plasmid DNA to these materials and to control polymers poly(ethyleneimine) (PEI) and poly(ethyleneimine)-octanamide," reported B.R. Twaites and colleagues, University of Portsmouth, School of Pharmacy and Biomedical Science.

"Complexes of plasmid DNA with then noresponsive cationic polymers containing PNIPAm displayed variations in gel retardation behavior above and below polymer phase transition temperatures, with a high molecular weight linear cationic PNIPAm co-polymer forming complexes with reduced affinity above LCST whereas a branched PEI-PNIPAm co-polymer bound with higher affinity above the PNIPAm phase transition.

"The thermoresponsive polymers also exhibited changes in particle morphology across the same temperature ranges with polymer DNA complexes prepared at N/P ratios ...