10% chol.

1. 2% chol. 5% chol. Tapping Mode 5 m 5 m 5 m 5 m 5 m 5 m 2% chol. 5% chol. 20 μm 20 μm 20 μm Langmuir-Schaeffer deposition monolayer Mica substrate mica 7.5 m PLA2 hydrolysis PLA2 hydrolysis Wilhelmy balance barrier barrier Aqueous subphase 5 4.5 nm nm -4.5 -5 0 10 mm 0 10 mm monolayer mica Langmuir-Blodgett deposition bilayer mica Mica substrate The Use of Self-Patterned Phospholipid Films for Directed Enzyme Lithography N.Y.-W. TANG and A. Badia, Department of Chemistry, University of Montreal, C.P. 6128, succursale Centre-ville Montreal, Qc, H3T 1J4, nathalie.tang@umontreal.ca • Objectives • Generate phospholipid-based surface patterns from phase-separated monolayers using the Langmuir-Blodgett technique • Study the effect of lineactants on the pattern morphology • Demonstrate that a striped phospholipid bilayer prepared by the Langmuir-Blodgett technique can be used for enzyme nanolithography Phospholipases Langmuir-Blodgett Monolayers of DPPC/DLPC • PLA2, a calcium-dependent and interfacially-active enzyme, catalyzes the cleavage of the sn-2 acyl ester linkage of glycerophospholipids, yielding a fatty acid and lysophospholipid. • The naturally occuring L form of the lipid is hydrolyzed, PLA2 binds but does not cleave the D form. Structures of Phospholipids and Lineactant cholesterol DPPC, C16; Tm = 41°C PLA2 Degradation of a Striped D--DPPC/L--DLPC Bilayer Stripe Formation Mechanism DLPC, C12; Tm = -1 °C Langmuir Monolayers of Phospholipids P. Moraille and A. Badia, Langmuir2002, 18, 4414-4419 PLA2 Degradation of a Striped L--DPPC/ DEPC Bilayer Solid-Supported Phospholipid Films Effect of Cholesterol Lineactant on the Domain Morphology for a 50/50 DPPC/DLPC Mixture at  = 32 mN/m 10% chol. 10% chol. Atomic Force Microscopy (AFM) Characterization of the Surface Morphology • Conclusions and Future Work on Enzyme Nanolithography • PLA2 stereospecifically hydrolyzes the L-a-phospholipid enantiomer in bilayer templates. • PLA2 only hydrolyzes dialkylphosphatidylcholines in bilayer templates. • The regularity of the monolayer and bilayer stripe patterns will be improved. • The PLA2 enzyme performance will be demonstrated for different enantiomer templates . • Alkyl tail-functionalized phospholipids will be used to spatially direct the deposition of metal nanoparticles for the generation of 2D optical gratings. • Enzyme Nanolithography • Enzymes make interesting nanolithographic tools due to their ability to catalyze chemical reactions with high efficiency and specificity under mild conditions and aqueous environment. • The stereospecificity exhibited by certain enzymes can be exploited to spatially direct their activity to certain regions of a patterned surface, as shown herein. • We have investigated the phospholipase A2 (PLA2 ) hydrolysis of stereochemically-differentiated DPPC/DLPC and chemically-differentiated DPPC/DEPC bilayers.