Submitted to: Controlled Release Society
Publication Type: Abstract Only
Publication Acceptance Date: 7/18/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Introduction: Polysaccharides are typically considered to be environmentally friendly materials because of their renewability, biodegradability, and biocompatibility. These properties are ideal when creating nanoparticle technology for delivery of bioactives. We developed methods for converting water-insoluble alpha-glucans produced using recombinant Leuconostoc mesenteroides glucansucrase and sucrose into novel nanoparticles [1,2]. In this work, we demonstrate that these alpha-glucan polysaccharide (alpha-GP) nanoparticles can be further developed into thin films. We also demonstrate that nanoparticles encapsulating a fluorescent dye can form films capable of slow release. Methods: Alpha-Glucan polysaccharides (at 0.25% w/v) in combination with cellulose nanofibers (CN) at 0–1.25% w/v was hydrated overnight in nanopure water and subsequently homogenized for 60 cycles at ~70 MPa to form nanoparticles. Film formation was conducted by aliquoting either five milliliters of the nanoparticles into a 2-in diameter polystyrene petri dish, or thirty (30) milliliters into 5 1/2-in diameter petri dishes, or forty (40) milliliters into rubber modes ~ 4 in by 6 1/2-in. Aliquoted nanoparticles were allowed to air-dry at room temperature to form thin films. Encapsulation and release were tested by incorporating 10 mM 5(6) carboxyfluorescein (CF) during the overnight hydration. Nanoparticles were then dialyzed for 2 hr prior to film formation. Results: Alpha-Glucan polysaccharide nanoparticles readily dried to form films of 6–16 µm thick when combined with cellulose nanofibers at 0–1.25% w/v. Visual characterization revealed that all films were flexible. Small films (2-in diameter) containing CN/alpha-GP at 2/1 to 5/1 formed on polystyrene retained a level of CF and were opaque. All small films except those containing 3/1 CN/alpha-GP cracked during drying. Films containing cellulose nanofibers/alpha-glucan polysaccharides at 3/1 ratio showed slow CF release for approximately 21 ½ hr. Larger films (5½ in diameter) containing 2/1 CN/alpha-GP formed on polystyrene were opaque, flexible, and without tears. Films containing 2/1 CN/alpha-GP formed on glass inside the plastic molds were less opaque and cracked only along the edges where film was in contact with the molds. Conclusion: Alpha-Glucan polysaccharides are a promising candidate as a source for making thin, biocompatible films that are capable of slow release. Thin films made alpha-glucan polysaccharide nanoparticles had a difference in transparency when formed on polystyrene versus glass. These films are further being characterized for encapsulation and release of bioactives. Acknowledgements: This work was supported by the U.S. Department of Agriculture which is an equal opportunity provider and employer. 1. Evans, K.O., et al., Development and Physical Characterization of a-Glucan Nanoparticles. Molecules (Basel, Switzerland), 2020. 25(17). 2. Cormier, R., G.L. Cote, and C.D. Skory, U.S. Patent Number 9708417B2. Nanoparticles and films composed of water-insoluble glucan. 2017, The United States of America, as represented by the Secretary of Agriculture, Washington, DC: USA. p.16. Presenter biography: Kervin Evans, as a research physical scientist at the U.S. Department of Agriculture in Peoria, IL, USA, works on developing nano/micro-encapsulation systems made from biopolymers and lipids. Learning Objectives Understand the ability of alpha-glucan nanoparticles to form thin films. Explain the contents release capability of alpha-glucan polysaccharide thin films.Evaluate the clarity of films formed on different surfaces.