@article {17609, title = {Dual stimuli responsive poly(N-isopropylacrylamide) coated chitosan scaffolds for controlled release prepared from a non residue technology}, journal = {JOURNAL OF SUPERCRITICAL FLUIDS }, volume = {66}, year = {2012}, month = {2012-06-04 00:00:00}, pages = {398-404}, publisher = {ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The first decade of the 21st century saw an increasing interest in the development of devices and biomaterials\ for\ delivery of bioactive substances that can be\ controlled\ by external\ stimuli. Herein we report the production of smart partially biodegradable\ scaffolds\ that exhibit pH- and temperature-responsive\ behavior and their effects on the\ release\ of\ a\ model protein and\ a\ drug of low molecular weight.\ Chitosan\ (CHT)\ scaffolds\ (pH sensitive) were\ coated/impregnated with\ a\ thermoresponsive polymer,\ poly(N-isopropylacrylamide) (PNIPAAm), by in situ synthesis of PNIPAAm within CHT micropores. Microarchitectural analysis by scanning electron microscopy and mercury intrusion porosimetry demonstrate that the coating of the pores inner structure could be efficiently achieved without\ a\ considerable loss of porosity of native CHT-scaffolds. Two different strategies were used to impregnate the polymeric devices: supercritical fluid impregnation\ for\ scaffold uptake with\ a\ model low molecular weight drug (ibuprofen) and bulk loading to impregnate\ amodel protein (bovine serum albumin, BSA). The\ release\ profiles showed\ a\ specific pattern according to pH and temperature. PNIPAAm temperature responsiveness is able to control BSA\ release\ but ibuprofen (Ibu)\ release\ is only mediated by pH environmental conditions. (c) 2011 Elsevier B.V. All rights reserved.

}, keywords = {BSA, Chitosan, Drug delivery, Ibuprofen, PNIPAAm, Stimuli responsive polymers, Supercritical carbon dioxide}, issn = {0896-8446}, doi = {10.1016/j.supflu.2011.10.015}, url = {http://apps.webofknowledge.com/full_record.do?product=UA\&search_mode=GeneralSearch\&qid=24\&SID=R26mYWbF6MIAgV5us3R\&page=1\&doc=1}, author = {Temtem, M. and Barroso, T. and Casimiro, T. and Mano, J. F. and Aguiar, R. A.} }