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Arrays of lipid bilayer and liposomes on polyelectrolytes

Arrays of lipid bilayer and liposomes on polyelectrolytes. Neeraj Kohli, Sachin Vaidya, Robert Ofoli, Mark Worden, Ilsoon Lee. Department of Chemical Engineering and Materials Science, Michigan State University. Presented at 2004 Annual AIChE Conference November 7 - 12, 2004, Austin, TX.

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Arrays of lipid bilayer and liposomes on polyelectrolytes

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  1. Arrays of lipid bilayer and liposomes on polyelectrolytes Neeraj Kohli, Sachin Vaidya, Robert Ofoli, Mark Worden, Ilsoon Lee Department of Chemical Engineering and Materials Science, Michigan State University Presented at 2004 Annual AIChE Conference November 7 - 12, 2004, Austin, TX Center for Nanostructured Biomimetic Interfaces

  2. Outline • Potential applications • Limitations of previous approaches • Our approach • Characterization techniques • Fluoresence microscopy • Total internal reflection fluorescence microscopy (TIRFM) • Fluoresence recovery after pattern photobleaching (EPI-FRAPP) Center for Nanostructured Biomimetic Interfaces

  3. Potential applications • Biosensors • Biocatalysis • Cell-cell communication • Studying membrane mediated processes • Development of drug screening devices Center for Nanostructured Biomimetic Interfaces

  4. Limitations of previous approaches • Applicable to limited number of substrates • No cushion between the lipid bilayer and the substrate • No ionic reservoir Approaches are needed to overcome these limitations Center for Nanostructured Biomimetic Interfaces

  5. Materials Lipids • DOPC: 1,2-Dioleoyl-sn-Glycero-3-Phosphocholine (zwitterion) • DOPA: 1,2-Dioleoyl-sn-Glycero-3-Phosphate (Monosodium Salt) (negatively charged) • NBD PC: 1-Palmitoyl-2-[6-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]hexanoyl]-sn-Glycero-3-Phosphocholine (zwitterion) Polyelectrolytes • PDAC: Poly(dimethyldiallylammonium chloride) (positively charged) • PAH: Poly(allylamine hydrochloride) (positively charged) • SPS: Sulfonated poly(styrene) ( negatively charged) m-dPEG acid Center for Nanostructured Biomimetic Interfaces

  6. 1 G. Decher , Science, 1997, 277, 1232. 2 A. Kumar and G. M. Whitesides, Appl. Phys. Lett., 1993, 63, 2002. 3 X. Jiang, H. Zheng, G. Shoshna, and P. T. Hammond, Langmuir, 2002, 18, 2607 Arrays of Lipid bilayers • Layer by layer assembly1, microcontact printing2 and polymer on polymer stamping3. • Two different schemes were used to make arrays of lipid bilayers • Scheme 1: either the PDAC or PAH patterned substrates were exposed to negatively charged liposomes • Scheme 2: m-dPEG acid patterns on PDAC were exposed to negatively charged liposomes Center for Nanostructured Biomimetic Interfaces

  7. Scheme 1 Center for Nanostructured Biomimetic Interfaces

  8. Technique Glass Slide PDAC (+ve) WATER SPS (-ve) WATER Center for Nanostructured Biomimetic Interfaces

  9. SPS(-ve) PDAC or PAH Glass slide Stamp Technique PDAC (+ve) or PAH (+ve) Center for Nanostructured Biomimetic Interfaces

  10. Fluorescence Center for Nanostructured Biomimetic Interfaces

  11. syringe pump TIRFM • Shallow evanescent wave depth (80nm) allows for selective surface illumination • Monitor the adsorption of liposomes on PDAC, PAH and m-dPEG acid prism Glass slide coated with PEMs spacer bottom slide Center for Nanostructured Biomimetic Interfaces

  12. Adsorption 140000 PDAC 120000 PDAC 90% DOPC 100000 10% DOPA 80000 Fluorescence (A.U) 60000 SPS 80 % DOPC 40000 20% DOPA 20000 SPS 0 0 1000 2000 3000 4000 Time (seconds) Center for Nanostructured Biomimetic Interfaces

  13. Scheme 2 m-dPEG acid PDAC SPS Center for Nanostructured Biomimetic Interfaces

  14. Fluorescence Center for Nanostructured Biomimetic Interfaces

  15. Adsorption of DOPA-DOPC on m-dPEG acid and PDAC 300000 250000 200000 PDAC Fluorescence 150000 100000 PEG 50000 0 0 500 1000 1500 Time (seconds) Adsorption Center for Nanostructured Biomimetic Interfaces

  16. EPI-FRAPP Laser beam passes through Ronchi ruling placed in the image plane Center for Nanostructured Biomimetic Interfaces

  17. EPI –FRAPP recovery on PDAC Center for Nanostructured Biomimetic Interfaces

  18. EPI-FRAPP recovery on PAH Center for Nanostructured Biomimetic Interfaces

  19. Diffusion Coefficients Center for Nanostructured Biomimetic Interfaces

  20. Conclusions • Fabricated arrays of lipid bilayers • Applicable to large number of substrates • Cushion below the lipid bilayer • Fluorescence microscopy, TIRFM and FRAPP were used. • PDAC showed only 50% recovery • PAH showed almost complete recovery • PAH had higher diffusion coefficients Center for Nanostructured Biomimetic Interfaces

  21. Funding • Michigan Technology Tri-Corridor • Center for Fundamental Materials Research • MSU-Intramural Research Grant Program Center for Nanostructured Biomimetic Interfaces

  22. Thank you Center for Nanostructured Biomimetic Interfaces

  23. Polyelectrolytes sulfonated poly(styrene) poly(diallyldimethylammonium chloride) SPS PDAC Strong Polyelectrolytes Polycations Weak Polyelectrolytes Polyanions poly(acrylic acid) poly(ethyleneimine)

  24. DOPC DOPA NBD-PC

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