Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: The most important output of this seed project is to demonstrate the feasibility that carbohydrate nanoparticle-mediated systems can be used to stabilize and prolong the efficacy of antimicrobial peptides against food pathogens. Research publications, meeting presentations, and news release have been used to communicate and disseminate the results to the scientific community and general public. For example, research results were presented in 2009 and 2010 IFT annual meetings, meeting of the Illinois-Purdue Center for Agricultural and Pharmaceutical Nanotechnology (CAPN), and CSREES (NIFA) annual PI meetings. An NSF proposal based on some results of this seed grant was reviewed and a 3-year grant was awarded. Two related papers have been published, two papers accepted (published online), and one in review. Based on this work, A Purdue featured news (Dec. 7, 2010) was released with the title of "Nanoparticle gives antimicrobial ability to fight Listeria longer", and it was later reported by IFT Weekly Newsletter, Sciencedaily, Physorg, Nanowerk, and other scientific news agencies. These activities have enriched the knowledge base in the area of food science, nanoscience and nanotechnology, and biotechnology, and also contributed to the public awareness. PARTICIPANTS: Yuan Yao, PI, Department of Food Science, Purdue University. His role was to supervise the project and direct the work on the preparation and characterization of carbohydrate nanoparticles. Arun Bhunia, Co-PI, Department of Food Science, Purdue University. His role was to direct the work related to microbiological tests. Ganesan Narsimhan, Co-PI, Department of Agricultural and Biological Engineering. His role was to advise the work related to analysis of nanoparticles. Lin Bi, graduate student of the Department of Food Science. Her role was to prepare carbohydrate nanoparticles and conduct microbiological tests. Lei Huang, visiting student of the Department of Food Science. Her role was to analyze the structure of carbohydrate nanoparticles. TARGET AUDIENCES: The audiences include academic researchers such as faculty members and students in the areas of food safety and microbiology, bionanotechnology, and food chemistry. The audiences also include personnel from the food industry and agencies related to food safety. The efforts include meeting presentations, papers, news release, and Whistler Center reports. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
As indicated by CDC, listeriosis is a serious infection and has been recognized as an important public health problem; an effective strategy to reduce the risk of listeriosis will have profound impact to the society and may help to save lives. Antimicrobial peptides such as nisin are effective to inhibit Listeria; however, these compounds are often subjected to rapid depletion after initial application and lose activities very quickly. To solve this problem, we have developed two carbohydrate nanoparticle-mediated systems: (1) water-soluble or dispersible systems and (2) emulsion-based colloidal assembly, to prevent antibacterial compounds from rapid depletion. Both strategies can be perceived as a major alternative to "active packaging" in which the antibacterial compounds are incorporated in the packaging materials such as films for extended release. Using a nisin depletion model, it was shown that both strategies are very effective to retain nisin activity during extended storage. By using phytoglycogen octenyl succinate (PG-OS) nanoparticles, the anti-listerial activity of nisin can be retained for up to 21 days. By using PG-OS-stabilized emulsions, nisin activity can be maintained for up to 40 days. In a related work, we studied the function of PG-OS nanoparticles in stabilizing oil-in-water emulsions, which led to two paper publications. These studies provided fundamental knowledge of PG-OS-stabilized nano systems, which are important for designing PG-OS-mediated assemblies for prolonged release of antibacterial peptides. In addition, we probed the particulate structure of phytoglycogen using amyloglucosidase. It was found that, for an average nanoparticle, there is an increment of molecular density from the internal to external region. This structural feature is similar to that of synthetic dendrimers in which increased generation leads to increased density. This finding brings new insight on the biogenesis of phytoglycogen and may guide the structural engineering of carbohydrate nanoparticles.
Publications
- Scheffler, S.L., Huang, L., Bi, L. and Yao, Y. 2010. In vitro digestibility and emulsification properties of phytoglycogen octenyl succinate. Journal of Agricultural and Food Chemistry. Articles ASAP (http://pubs.acs.org/doi/abs/10.1021/jf904378e)
- Scheffler, S.L., Wang, X., Huang, L., San-Martin Gonzalez, F. and Yao, Y. 2010. Phytoglycogen octenyl succinate, an amphiphilic carbohydrate nanoparticle, and epsilon-polylysine to improve lipid oxidative stability of emulsions. Journal of Agricultural and Food Chemistry, 58:660-667
- Bi, L., Yang, L. Narsimhan, G., Bhunia, A., Yao, Y. 2010. Designing carbohydrate nanoparticles for prolonged efficacy of antimicrobial peptide. Journal of Controlled Release, accepted
- Huang, L., Yao, Y. 2010. Particulate structure of phytoglycogen nanoparticles probed using amyloglucosidase. Carbohydrate Polymers, accepted
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