Research: Lipid Nanotechnology
Lipid multilayer nanostructures on surfaces are a new type of nanomaterial made possible by recent advances in nanoscience [1-4]. They are layers of lipids on surfaces that are laterally structured, and thicker than a single lipid bilayer.(Figure 1) We use and develop novel methods to fabricate surface supported lipid nanostructures, including lipid dip-pen nanolithography and lipid multilayer stamping [1,4].(Figure 2) We use atomic force microscopy, optical microscopy and other methods in nanoscience to characterize nanostructure-function relationships .(Figure 3) Applications include biological sensor arrays , and novel cell-culture based drug screening platforms .(Figure 4)
Figure 1. Chemical and supramolecular structures of liposomes and surface-supported lipid nanostructures. a, The chemical structure of DOPC, a typical phospholipid used in this research. b, An example of one type of liposome supramolecular structure that self-assembles in water, in this case, a multilamellar liposome. c, Hypothetical structure of a surface-supported liposome (or nanostructure) on a surface where it does not spread.
Figure 2. Methods for making lipid multilayer nanostructures. a, Lipid dip-pen nanolithography [1,2] b Lipid multilayer stamping .
Figure 3. High-throughput optical quality control that uses fluorescence microscopy to determine heights as calibrated by atomic force microscopy (AFM) . a, Large-area fluorescence micrograph of a row of "FSU" patterns of different heights, seen as different fluorescence intensities. b, Enlargement of the area outlined in a. c, Determination of structure heights by means of calibrated fluorescence intensities. d, AFM image of the area shown in b. e, AFM height measurement of the same section measured optically in c.
Figure 4. Applications a, Biosensors  b Drug screening microarrays .
- 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).
- 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).
- O. A. Nafday, S. Lenhert, High-throughput optical quality control of lipid multilayers fabricated by dip-pen nanolithography, Nanotechnology 22, (2011).
- O. A. Nafday, T. W. Lowry, S. Lenhert, Multifunctional lipid multilayer stamping, Small 8, 1021-1028 (2012).
- A. Kusi-Appiah, N. Vafai, P. J. Cranfill, M. W. Davidson, S. Lenhert, Lipid multilayer microarrays for in vitro liposomal drug delivery and screening, Biomaterials 33, 4187-4194 (2012).