Micro- and Nanofabricating Lipid Patterns Using a Polymer-Based Wet Lift-Off
- PDF / 512,690 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 29 Downloads / 170 Views
Micro- and Nanofabricating Lipid Patterns Using a Polymer-Based Wet Lift-Off Reid. N. Orth1, Ismail. Hafez1, Min. Wu2, Bojan. Ilic1, Barbara Baird2, Theodore G. Clark3, and Harold G. Craighead1 1 School of Applied and Engineering Physics, 2Department of Chemistry, Cornell University, 3 Department of Immunology and Microbiology, Ithaca, NY 14853 ABSTRACT Accurate placement of biomaterials at nanoscale resolution opens new capabilities for biological sensing, cell manipulation, and control of cellular transduction cascades. We demonstrate that lipid molecules can be patterned on silicon using a polymer lift-off technique. Patterned lipid bilayers serve as biomaterial patterning platforms useful for studies of cellular function. Submicron feature sizes were achieved using this templating technique which is suitable for delicate biomaterials1. Projection lithography and reactive ion etching were used to pattern a Parylene-coated surface. The patterned surface was subsequently exposed to 100 nm unilamellar lipid vesicles that bound to the native oxide surfaces of silicon and spread to form supported lipid bilayers. The nanoscale pattern is realized as the polymer is peeled away in deionized water. The versatility of this method is demonstrated by the successful preparation of functionalized lipid bilayer surfaces. Specific intermolecular interactions were demonstrated between supported membranes: DPPE-PE (2000) biotin/avidin, dinitrophenol (DNP)-conjugated lipids/anti-DNP IgE, and cationic lipid and M13 dsDNA:YOYO-1. INTRODUCTION Cell membranes are composed of lipids and contain numerous ligands that direct cellsurface, cell-cell, and extracellular interactions. Micro- and nanofrabrication-directed biomaterial patterning offers a greater control of cell analysis than bath application of biological materials. There have been many methods used to pattern biomaterials using microfabrication. The microcontact printing process uses a poly(dimethyl siloxane) (PDMS) elastomeric stamp to pattern a wide array of chemicals, self-assembled monolayers (SAMs) and biomaterials2-4. Photoactivation has allowed molecules to be patterned using conventional photolithographic methods5-6. Ink-jet printing have been used to pattern proteins7. While these are versatile and widely-used patterning methods, they have the potential for surface fouling, nonspecific binding after primary layer application, and biomolecular denaturation from drying. Supported lipid bilayer membranes offer experimental models for studying the characteristic cell membrane properties. Membrane kinetics and vesicle binding have been analyzed with a quartz crystal microbalance8. Lipid vesicles binding/supported lipid bilayers formation have been analyzed using surface plasmon resonence9. Amperometry, cyclic voltametry, and impedance studies have analyzed transmembrane molecular properties and ion conductance10. The present work reviews a method for patterning biomaterials using a dry polymer lift-off technique11 as detailed in Figure 1. The patterning of lipids is based u
Data Loading...
