AFM Rasterkraftmikroskop

• Subject Area: Basic Research in Biology and Medicine
• Term: Funded in 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 194951440

• Final Report Year: 2015

Final Report Abstract

Bidirectional determination of the orientation of nanoscale collapse reservoirs formed within a Langmuir film at the air-aqueous interface. The investigation of Langmuir films is the primary tool to characterize surface-associated reservoirs of the pulmonary lung surfactant. Bidirectional surface imaging of films transferred on porous substrates showed collapse towards air-side. Impact of hydrophilic nanoparticles (NPs) on the pulmonary surfactant and their size on lung surfactant model systems. The distribution of AmOrSil20 and polyorganosiloxane NPs and their effect on nanoscale collapse reservoirs and domain structures within the film were analyzed. Multilayer protrusion formation was stabilized in presence of ~ 140 nm sized NP’s. Characterizing the structure and function of the tear fluid lipid layer employing artificial binary and ternary lipid mixtures containing DPPC, cholesteryl esters and tri-acyl-glycerols as well as natural meibomian lipids. In presence of ectoine and tri-acyl-glycerols droplet like structures were determined which were similar to the natural meibomian lipids, showing exclusion of glycerols from the lipid film. Results may affect treatment of the dye-eye syndrome caused by an increased evaporation rate of the tear film. Investigation of mutual Phosphatidylinositol-4,5-bisphosphate (PIP2) preference for silicon substrates used in supported lipid bilayers (SLBs) for analyzing protein-lipid interactions. An initial and time depending loss of surface associated lipid binding sites in the SLB could be efficiently stabilized by incorporation of Phosphatidylserine into plasma membrane mimicking lipid models. These where further applied to analyze lipid binding characteristics of Annexin A2 to PIP2 and cholesterol containing model membranes. Unique models containing PIP2 and cholesterol showed a pH dependent efficiency of bilayer formation. Further experiments verified the structural integrity of SLBs employed in lipid-protein investigations and Biosensors. Analysis of peptide-based hydrogels which form supramolecular aggregates in pH dependent manner. Thiol-ene-click chemistry of free thiol functions on Cys residues as basis for molecular recognition. Project covers nanomolecular assembling of cysteine-tri-peptides as functional materials characterized on silicon support. Development and characterization of structured natural and synthetic polymers applying inverse Diels- Alder reactions by micro contact printing (µCP). Bioorthogonal surfaces were specifically addressable by proteins with high pattern resolutions. Establishing of coiled coil motifs as molecular recognition units for the immobilization of liposomes on patterned surfaces employing µCP. Morever the instrument was used for the investigation of the role of functionalized surfaces for cellular recognition and adhesion.

Publications

• , Immobilization of Liposomes and Vesicles on Patterned Surfaces by a Peptide Coiled- Coil Binding Motif. Angewandte Chemie International Edition 2012, 51, 12616
  J. Voskuhl, C. Wendeln, F. Versluis, E.-C. Fritz, O. Roling, H. Zope, C. Schulz, S. Rinnen, H. F. Arlinghaus, B. J. Ravoo, A. Kros
  
• Bidirectional Surface Analysis of Monomolecular Membrane Harboring Nanoscale Reversible Collapse Structures, Nano Letters 2013
  A.K. Sachan, H.-J. Galla
  
• Periodic mesoporous organosilica based nanocomposite hydrogels as new biocompatible threedimensional scaffolds. Angew.Chem.Int; 52, 1156-1160
  ehr NS, Prasetyanto EA, Galstyan A, Benson K, Ergün B and Galla HJ
  
• (2014); Cell adhesion behaviour in enantiomerically functionalized 3D hydrogel scaffolds. Macromol.Biosci; 14, 793-798
  Benson K, Galla HJ and Kehr NS
  
• (2014); Enantiomerically functionalized periodic mesoporous organosilicia monolayers fort he study oft he effect of surface chirality on cell adhesion behavior; RSC Adv. 5, 5704-5710
  Kehr SN, Galla HJ, Riehemann K and Fuchs H
  
• Biophysical investigations of the structure and function of the tear fluid lipid layers and the effect of ectoine. Part B: Artificial lipid films. Biochimica et Biophysica Acta (BBA) - Biomembranes 2014, 1838, 2716
  M. Dwivedi, M. Brinkkötter, R. K. Harishchandra, H.-J. Galla
  
• Formation and Characterization of Supported Lipid Bilayers Containing Phosphatidylinositol-4,5-bisphosphate and Cholesterol as Functional Surfaces. Langmuir 2014, 30, 14877
  P. Drücker, D. Grill, V. Gerke, H.-J. Galla
  
• Importance of phospholipid bilayer integrity in the analysis of protein-lipid interactions. Biochem. Bioph. Re. Co. 2014, 453, 143
  P. Drücker, V. Gerke, H.-J. Galla
  
• Size Influences the Effect of Hydrophobic Nanoparticles on Lung Surfactant Model Systems. Biophysical Journal 2014, 106, 289
  M. Dwivedi, R. K. Harishchandra, O. Koshkina, M. Maskos, H.-J. Galla
  
• Surface patterning with natural and synthetic polymers via an inverse electron demand Diels-Alder reaction employing microcontact chemistry. Organic & Biomolecular Chemistry 2014, 12, 7828
  O. Roling, A. Mardyukov, S. Lamping, B. Vonhoren, S. Rinnen, H. F. Arlinghaus, A. Studer, B. J. Ravoo
  
• Understanding the Mutual Impact of Interaction between Hydrophobic Nanoparticles and Pulmonary Surfactant Monolayer. Small 2014, 10, 1069
  A. K. Sachan, H.-J. Galla
  
• pH response and molecular recognition in a low molecular weight peptide hydrogel. Organic & Biomolecular Chemistry 2015, 13, 561
  S. C. Lange, J. Unsleber, P. Drücker, H.-J. Galla, M. P. Waller, B. J. Ravoo