Nisin is often used as a preservative in meats and cheeses to prevent the growth of lactic acid bacteria and Listeria monocytogenes, a deadly pathogen. The problem is that nisin needs to be preserved itself for it to work for more than a few days. Purdue University researchers have now developed carbohydrate nanoparticles that can slow-release nisin over time.
Yao used two strategies to attract nisin to the phytoglycogen nanopoarticles. First, he was able to negatively charge the surface of the nanoparticle and use electrostatic activity to attract the positively charged nisin molecules. Second, he created a partially hydrophobic condition on the surface of the nanoparticle, causing it to interact with partially hydrophobic nisin molecules. When the particles are hydrophobic, or repel water, they become attracted to each other.
“Both strategies may work together to allow nanoparticles to attract and stabilize nisin,” Yao said, “This could substantially reduce the depletion of nisin in various systems.”
For practical use, Yao said a solution containing the nanoparticles and free nisin could be sprayed onto foods or included in packaging. The solution requires a balance of free nisin and nisin on the nanoparticles.
“When you reduce the amount of free nisin, it will trigger a release of more nisin from the nanoparticles to re-establish the equilibrium,” Yao said. “There will be a substantial amount of nisin preserved to counteract the Listeria.”
Using a model, Yao said a sufficient amount of nisin to combat Listeria could be preserved for up to 21 days.
Link: Nanoparticle gives antimicrobial ability to fight Listeria longer …
Abstract in Journal of Controlled Releas: Designing carbohydrate nanoparticles for prolonged efficacy of antimicrobial peptide