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10 results on '"Mantz, H."'

1. Structural evolution of protein-biofilms: Simulations and Experiments

Author

Schmitt, Y., Hähl, H., Gilow, C., Mantz, H., Jacobs, K., Leidinger, O., Bellion, M., and Santen, L.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

The control of biofilm formation is a challenging goal that has not been reached yet in many aspects. One is the role of van der Waals forces and another the importance of mutual interactions between the adsorbing and the adsorbed biomolecules ('critical crowding'). Here, a combined exeperimental and theoretical approach is presented that fundamentally probes both aspects. On three model proteins, lysozyme, {\alpha}-amylase and bovine serum albumin (BSA), the adsorption kinetics is studied. Composite substrates are used enabling a separation of the short- and the long-range forces. Though usually neglected, experimental evidence is given for the influence of van der Waals forces on the protein adsorption as revealed by in situ ellipsometry. The three proteins were chosen for their different conformational stability in order to investigate the influence of conformational changes on the adsorption kinetics. Monte Carlo simulations are used to develop a model for these experimental results by assuming an internal degree of freedom to represent conformational changes. The simulations also provide data on the distribution of adsorption sites. By in situ atomic force microscopy we can also test this distribution experimentally which opens the possibility to e.g. investigate the interactions between adsorbed proteins., Comment: 13 pages, 10 figures; submitted

Published
2010

6. Dynamics and structure formation in thin polymer melt films

Author

Daniel Podzimek, Renate Konrad, Ralf Seemann, Chiara Neto, Stefan Schlagowski, Stephan Herminghaus, Hubert Mantz, Karin Jacobs, Fetzer, Renate, Seemann, R, Herminghaus, Stephan, Neto, C, Schlagowski, S, Podzimek, D, Mantz, H, and Jacobs, K

Subjects
Spinodal, Materials science, business.industry, Drop (liquid), Condensed Matter Physics, Surface tension, Scanning probe microscopy, Optics, General Materials Science, Dewetting, Wetting, Thin film, Composite material, Glass transition, business
Abstract

The stability of thin liquid coatings plays a fundamental role in everyday life. We studied the stability conditions of thin (3 to 300 nm) liquid polymer films on various substrates. The key role is played by the effective interface potential of the system air/film/substrate, which determines the dewetting scenario in case the film is not stable. We describe in this study how to distinguish a spinodal dewetting scenario from heterogeneous and homogeneous dewetting by analysing the emerging structures of the film surface by e.g. Minkowski measures. We also include line tension studies of tiny droplets, showing that the long-range part of does affect the drop profile, but only very close to the three phase boundary line. The dynamic properties of the films are characterized via various experimental methods: the form of the dewetting front, for example, was recorded by scanning probe microscopy and gives insight into the boundary condition between the liquid and the substrate. We further report experiments probing the viscosity and the glass transition temperature of nm-thick films using e.g. ellipsometry. Here we find that even short-chained polymer melts exhibit a significant reduction of the glass transition temperature as the film thickness is reduced below 100 nm.

Published
2005

7. Comprehensive measurements of salivary pellicle thickness formed at different intraoral sites on Si wafers and bovine enamel.

Author

Güth-Thiel S, Kraus-Kuleszka I, Mantz H, Hoth-Hannig W, Hähl H, Dudek J, Jacobs K, and Hannig M

Subjects
Adult, Animals, Cattle, Female, Humans, Kinetics, Male, Dental Enamel chemistry, Dental Pellicle chemistry, Saliva chemistry, Silicon Compounds chemistry
Abstract

The salivary pellicle is a thin acellular film formed on orally exposed surfaces by adsorption of macromolecules from the oral fluids and serves as a protective layer in the maintenance of oral health. Pellicle thickness measurements are a central tool helping to understand how exogenous manipulations may influence pellicle formation. This is of particular importance for the investigation of new preventive and therapeutic approaches. In the present study we determined the kinetics of the in situ pellicle thickness formation at different intraoral sites and investigated how pellicle formation occurs in different individuals. To address the kinetic aspect, the thickness of the in situ pellicle was determined after formation periods of 3 min, 30 min and 120 min. The thickness of the pellicle was either measured on silicon wafers by ellipsometry or on bovine enamel by transmission electron microscopy. We found a physiologically important rapid pellicle formation phase within the first minutes and a slow pellicle formation phase between 30 min and 120 min. Furthermore, our results identify significant inter-individual differences both for the pellicle thickness and for the formation kinetics, indicating the consideration of individual-specific differences of the pellicle layer as an important aspect for future studies., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Published
2019
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8. Evidence for capillarity contributions to gecko adhesion from single spatula nanomechanical measurements.

Author

Huber G, Mantz H, Spolenak R, Mecke K, Jacobs K, Gorb SN, and Arzt E

Subjects
Adhesiveness, Adsorption, Animals, Capillary Action, Humidity, Lizards physiology
Abstract

The hairy attachment system on a gecko's toes, consisting of one billion spatulae in the case of Gekko gecko [Ruibal, R. & Ernst, V. (1965) J. Morphol. 117, 271-294], allows it to adhere to nearly all surface topographies. The mechanistic basis for gecko adhesion has been intensely investigated, but the lowest hierarchical level, that of the spatula, has become experimentally accessible only recently. This report details measurements of the adhesion force exerted by a single gecko spatula for various atmospheric conditions and surface chemistries. Through judicious choice and modification of substrates, the short- and long-range adhesive forces are separated. In contrast to previous work [Autumn, K., Sitti, M., Liang, Y. C. A., Peattie, A. M., Hansen, W. R., Sponberg, S., Kenny, T. W., Fearing, R., Israelachvili, J. N. & Full, R. J. (2002) Proc. Natl. Acad. Sci. USA 99, 12252-12256], our measurements clearly show that humidity contributes significantly to gecko adhesion on a nanoscopic level. These findings are crucial for the development of artificial biomimetic attachment systems.

Published
2005
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