Lipid multilayer gratings are a new type of label free transducer based on fluid diffraction gratings on a surface.(1) Microstructured oil droplets regularly spaced at the wavelength of visible light function as diffraction gratings. When the liquid droplets interact with an analyte, droplet shape changes due to the interfacial forces involved, resulting in a detectable change in the intensity of light diffracted from the gratings. The mechanism of biosensing relies on a balance between stability and instability of the lipid micro/nanostructures, and an understanding of the interfacial and adhesion properties of micro and nanoscopic oil droplets is necessary for biosensing applications. The use biofunctional phospholipids as the oil enables specific detection of analytes such as proteins in solution. The crucial property of the grating that allows detection is the lipid multilayer thickness, which must be controlled between ~10-100 nm. Methods for fabricating the gratings include dip-pen nanolithography(2) and nanointaglio.(3) Importantly, these fabrication processes allow the integration of multiple materials on the same surface, enabling the fabrication of label free biosensor arrays. Progress in the development of functionalized multimaterial sensor arrays will be presented.
1. S. Lenhert, F. Brinkmann, T. Laue, S. Walheim, C. Vannahme, S. Klinkhammer, M. Xu, S. Sekula, T. Mappes, T. Schimmel, H. Fuchs, Lipid multilayer gratings.Nature Nanotechnology 5, 275-279 (2010). 2. S. Lenhert, P. Sun, Y. H. Wang, H. Fuchs, C. A. Mirkin, Massively parallel dip-pen nanolithography of heterogeneous supported phospholipid multilayer patterns. Small 3, 71-75 (2007). 3. T. W. Lowry, A. Kusi-Appiah, J. Guan, D. H. V. Winkle, M. W. Davidson, S. Lenhert, Materials Integration by Nanointaglio. Advanced Materials Interfaces, (In Press).