Optimization of synthesis process of thermally-responsive poly-n-isopropylacrylamide nanoparticles for controlled release of antimicrobial hydrophobic compounds
Date
2014-10-29Metadata
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The goal of this study was to develop an effective method to synthesize poly-n-isopropylacrylamide
(PNIPAAM) nanoparticles with entrapped cinnamon bark
extract (CBE) to improve its delivery to foodborne pathogens and control its
release with temperature stimuli. CBE was used as a model for hydrophobic
natural antimicrobials. A top-down procedure using crosslinked PNIPAAM was
compared to a bottom-up procedure using NIPAAM monomer. Both processes
relied on self-assembly of the molecules into micelles around the CBE at 40 °C.
Processing conditions were compared including homogenization time of the
polymer, hydration time prior to homogenization, lyophilization, and the effect
of particle ultrafiltration. The top-down versus bottom-up synthesis methods
yielded particles with significantly different characteristics, especially their
release profiles and antimicrobial activities. The synthesis methods affected
particle size, with the bottom-up procedure resulting in smaller (P < 0.05) diameters
than the top-down procedure. The controlled release profile of CBE from
nanoparticles was dependent on the release media temperature. A faster, burst
release was observed at 40 °C and a slower, more sustained release was observed
at lower temperatures. PNIPAAM particles containing CBE were analyzed for
their antimicrobial activity against Salmonella enterica serovar Typhimurium
LT2 and Listeria monocytogenes Scott A. The PNIPAAM particles synthesized
via the top-down procedure had a much faster release, which led to a greater
(P < 0.05) antimicrobial activity. Both of the top-down nanoparticles performed
similarly, therefore the 7 min homogenization time nanoparticles would be the
best for this application, as the process time is shorter and little improvement
was seen by using a slightly longer homogenization.
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Citation
Hill, Laura; Gomes, Carmen (2014). Optimization of synthesis process of thermally-responsive poly-n-isopropylacrylamide nanoparticles for controlled release of antimicrobial hydrophobic compounds. Materials Research Express. Available electronically from https : / /hdl .handle .net /1969 .1 /154650.
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