title: Comparative height measurements of dip-pen nanolithography-produced lipid membrane stacks with atomic force, fluorescence, and surface-enhanced ellipsometric contrast microscopy.
abstract: Dip-pen nanolithography (DPN) with phospholipids has been shown to be a powerful tool for the generation of biologically active surface patterns, but screening of the obtained lithographic structures is still a bottleneck in the quality control of the prepared samples. Here we performed a comparative study with atomic force microscopy (AFM), fluorescence microscopy (FM), and surface-enhanced ellipsometric contrast (SEEC) microscopy of phospholipid membrane stacks consisting of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) with high admixing of 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine-N-[6-[(2,4-dinitrophenyl)amino]hexanoyl] (DNP Cap PE) produced by DPN. We present a structural model of membrane stacking based on the combined information gained from the three microscopic techniques. Domains of phase-separated DNP Cap PE can be detected at high DNP Cap PE admixing that are not present at medium or low admixings. While the optical methods allow for a high-throughput screening of lithographic structures (compared to AFM), it was found that, when relying on FM alone, artifacts due to phase-separation phenomena can be introduced in the case of thin membrane stacks.
authors.affiliation: Institute of Nanotechnology (INT) and Karlsruhe Nano Micro Facility (KNMF), Karlsruhe Institute of Technology (KIT), Hermann-Von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany. michael.hirtz@kit.edu
authors.forename: Michael
authors.initials: M
authors.lastname: Hirtz
authors.forename: Rémi
authors.initials: R
authors.lastname: Corso
authors.forename: Sylwia
authors.initials: S
authors.lastname: Sekula-Neuner
authors.forename: Harald
authors.initials: H
authors.lastname: Fuchs
mesh_terms: D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D008968:Molecular Conformation; D036103:Nanotechnology; D010743:Phospholipids / Q000737:chemistry*; D011327:Printing
chemical_list: D010743:Phospholipids