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Our previous work has demonstrated the construction of phytoglycogen-based dendrimers and their complexation with nisin and chitosan. The nano-encapsulation strategy has been proved to be effective. In this project, we will tailor the structure of phytoglycogen-based dendrimers and adjust their complexation parameters with nisin and chitosan. Enzyme treatment and succinylation will be conducted to modulate the internal structure of phytoglycogen molecules and introduce negative charge to absorb positively charged molecules such as nisin and chitosan. The pattern of release of nisin and chitosan from the complexation will be examined in the presence of bacteria cells of Listeria monocytogenes. The impact of environment (such as pH and enzymes) on the complexation will be studied.
NON-TECHNICAL SUMMARY: In this proof-of-concept project, we will construct food-grade dendrimers and use them to deliver antibacterial peptide. We have discovered that phytoglycogen, a naturally occurred carbohydrate dendrimer, can be enzymatically and chemically modified to interact with bioactive peptide (nisin) and polysaccharide-based polyelectrolyte (chitosan). Based on this finding, we will design a nano-system for a controlled release of antibacterial activities. The electrostatic interactions and structural compatibility among phytoglycogen dendrimer, nisin, and chitosan allow for a rapid self-assembly of nano-encapsulation particles (50-80 nm) in mild conditions (room temperature and regular food pH). The nano delivery system formed showed structural integrity and superior stability due to a precise control of surface charge at each step of nano-fabrication. In this project we will tailor individual steps including dendrimer construction, dendrimer-nisin adsorption, and dendrimer-nisin-chitosan complexation. A number of nano-encapsulation preparations will be compared for their prolonged antibacterial properties, and the most suitable formulation will be identified. Models using agar plate and turkey meat will be used to evaluate the antibacterial efficacy of encapsulated nisin. This project will initiate the fundamentally novel research of food-grade dendrimer and use nisin nano-encapsulation system to demonstrate the versatility of phytoglycogen-based dendritic delivery system. The system established may benefit the enhancement of food safety and nutrition and have impacts on non-food areas such as drug delivery.
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APPROACH: Our previous work has demonstrated the construction of phytoglycogen-based dendrimers and their complexation with nisin and chitosan. The nano-encapsulation strategy has been proved to be effective. In this project, we will tailor the structure of phytoglycogen-based dendrimers and adjust their complexation parameters with nisin and chitosan. Enzyme treatment and succinylation will be conducted to modulate the internal structure of phytoglycogen molecules and introduce negative charge to absorb positively charged molecules such as nisin and chitosan. The pattern of release of nisin and chitosan from the complexation will be examined in the presence of bacteria cells of Listeria monocytogenes. The impact of environment (such as pH and enzymes) on the complexation will be studied.