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A capstone course for BioSUCCEED :

Biomass Fundamentals Modules 19 : Higher Order Functionality in Biomass: Surface Active Materials. A capstone course for BioSUCCEED : Bio products S ustainability: a U niversity C ooperative C enter of E xcellence in ED ucation.

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A capstone course for BioSUCCEED :

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  1. Biomass FundamentalsModules 19: Higher Order Functionality in Biomass:Surface Active Materials A capstone course for BioSUCCEED: BioproductsSustainability: a University Cooperative Center of Excellence in EDucation The USDA Higher Education Challenge Grants program gratefully acknowledged for support

  2. This course would not be possible without support from: USDA Higher Education Challenge (HEC) Grants Program www.csrees.usda.gov/funding/rfas/hep_challenge.html

  3. Article of Interest for Discussion • “Comparison of the Leakage of Carboxyfluorescein from Symmetric and Asymmetric-Acyl Chain Phospatidylcholine Vesicles” – Wiedmann, Timothy S.; Salmon, A.; Perkins, Walter R. Pharm. Res.1993, 10, 147-151. • http://springer.metapress.com/content/jm857702236gu462/fulltext.pdf

  4. Building blocks for containers: amphiphiles Surfactant Tail Surfactant Head Surfactant Monomers Micelle

  5. Structure of a Vesicle • Amphiphiles used to make it • Grossly – bilayer structure versus micelle • Unilamellar sphere (SLV) vs MLV (multilamellar) • Hydrophilic core & bulk • Sandwich is hydrophobic

  6. Vesicles as containers • Modify them by employing amphiphiles that moderate permeability • Use symmetric & asymmetric amphiphiles • Make mixed chain, partial interdigitated bilayer

  7. Symmetric amphiphile (16,16 PC)

  8. Asymmetric amphiphile (20,12 PC) 18 10

  9. DSC profiles for vesicles (multilamellar) Multilamellar dispersions • High sensitivity DSC • 20/hr scan rate • Gel-to-liquid crystalline transitions different • Mean diameters = 22090 nm & 210 85 nm for 16/16 PC & 20/12/ PC, respectively Extruded dispersions 20/12 PC 16/16 PC

  10. Time dependence of guest release • Leakiness originates from gel-to-liquid transitions • Carboxyfluorescein is the guest molecule • In the 16/16 PC (circles), there is more release than 20/12 PC (squares) 42C 48C

  11. Release of guest (carboxyfluorescein) as a function of temperature • In 20/12 PC, there is little correlation between % release and temperature (closed circles) • In 16/16 PC, there is definite dependency on T

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