Characterization of temperature and pH-responsive poly-N-isopropylacrylamide-co-polymer nanoparticles for the release of antimicrobials
Abstract
Chitosan and alginate are both pH-responsive biopolymers extracted from
crustacean exoskeletons and brown algae, respectively. Poly-N-isopropylacrylamide
(PNIPAAM) is a hydrogel that becomes hydrophobic at a
lower-critical solution temperature. This study sought to combine pH- and
temperature-responsive polymers via crosslinking, in order to create a dualstimuli
responsive polymer for hydrophobic antimicrobial compounds delivery,
improving their antimicrobial effects. Cinnamon bark extract (CBE) was used as
a model for hydrophobic antimicrobial. Two co-polymers were synthesized to
create two nanoparticles types: chitosan-co-PNIPAAM and alginate-co-PNIPAAM.
Nanoparticles were formed from the resulting co-polymers using a selfassembly
top-down process followed by glutaraldehyde or calcium chloride
crosslinking. These nanoparticles were then used as controlled delivery vehicles
for CBE, whose rapid release could be triggered by specific external stimuli. For
the same pH and temperature conditions, the chitosan-co-PNIPAAM nanoparticles
were significantly more potent bacterial inhibitors against both pathogens
and also exhibited a faster CBE release over time as well as slightly higher
entrapment efficiency. The alginate-co-PNIPAAM nanoparticles were significantly
smaller and exhibited a slow, gradual release over a long time period.
Although both nanoparticles were able to effectively inhibit pathogen growth at
lower (P < 0.05) concentration than free CBE, the chitosan-co-PNIPAAM
nanoparticles were more effective in delivering a natural antimicrobial with
controlled release against foodborne pathogens.
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Citation
Hill, Laura; Gomes, Carmen (2014). Characterization of temperature and pH-responsive poly-N-isopropylacrylamide-co-polymer nanoparticles for the release of antimicrobials. Materials Research Express. Available electronically from https : / /hdl .handle .net /1969 .1 /154698.
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