Personnel
Michael Grunze
Co-Director
Institute for Molecular Biophysics
TJL - 207-288-6724
UMaine - 207-581-2285
mhgrunze@jax.org
www.pci.uni-heidelberg.de/apc/
Research:
New Spectoscopies, New Surfaces and Cells
X- ray microscopy and spectroscopy applied to melanosomes. Melanosomes are specialized intracellular membrane bound organelles that produce and store melanin pigment. The composition of melanin and distribution of melanosomes determine the color of many mammalian tissues, including the hair, skin, and iris. Melanin absorbs light, allowing the iris to regulate the amount of light entering the eye and protecting the body from the damaging effects of UV radiation. However, the presence of melanosomes within a tissue also carries potential risks. The proteins and chemical intermediates of melanin synthesis can be damaging to cells and must be sequestered within melanosomes to prevent cellular damage. Disruption of this capacity may result in cell death. The biological processes and ultrastructural components contributing to the ability of melanosomes to contain or detoxify these compounds are largely unknown. Better understanding of these processes would have a direct biomedical impact on several human diseases of pigmented tissues such as, cutaneous malignant melanoma (cancer arising from pigmented cells) or pigmentary glaucoma. The goal of this project is to adapt X-ray imaging techniques to the study of melanosomal ultrastructure and the mechanisms regulating the distribution of toxic molecules associated with melanin production. In addition to X-ray microscopy we are applying x-ray fluorescence measurements of the chemical composition of single organelles, at the ESRF in Grenoble /France and Bessy/ Germany. The project is in collaboration with Simon John, The Jackson Laboratory; Mike Anderson, University of Iowa; C. Jacobson and J. Kirz, SUNY at Stony Brook.
Sum Frequency Generation (SFG) on membrane models and Monte Carlo simulations on water in phospholipid membranes. In collaboration with David Neivandt and Igor Prudovsky, SFG experiments on membrane models are conducted with the SFG apparatus at the University of Heidelberg. Complementing these experiments are Grand Canonical Monte Carlo Calculations (GCMC) on phospholipid bilayers. They represent the major structural element of biological membranes. Knowledge of the interaction forces operating between the bilayers in water is a prerequisite for understanding all inter-membrane coupling phenomena such as adhesion, stacking, and fusion. We are undertaking a first attempt to evaluate the water-mediated force between phospholipid bilayers in a straightforward way, via computer simulation of the Surface-Force Apparatus (SFA) experiment. To mimic the open configuration of SFA measurements, where water is confined between two immobilized bilayers while being allowed to exchange molecules with a bulk water reservoir, the GCMC technique is used. The simulations are made computationally feasible by resorting to enhanced sampling techniques such as the excluded volume mapping and Swendsen-Wang filtering for water insertions and the optimized local-move Monte Carlo method for conformational sampling. The simulated force-distance relationships in combination with the molecular-level structural knowledge will provide a deeper insight into the nature of the interactions between biomembranes.
Chemical Nanolithography approaches to bio-functional surfaces. The development of simple and rapid techniques for the site-specific immobilization of single molecules or molecular aggregates is critical in many areas of nanoscience, e.g. for the definition of molecular contacts in ‘molecular electronics’ or the miniaturization of high throughput assays in molecular biology. Different techniques and strategies based on Scanning Probe Microscopies have been developed to chemically pattern substrates on a molecular length scale; they are, however, limited in speed and are difficult to combine with conventional microfabrication techniques. Together with Wolfgang Eck and others we developed alternative paths to create molecular nanopatterns by combining lithography with novel self-assembling materials (SAMs). Since SAMs show specific sensitivity to irradiation, aliphatic and aromatic SAMs have been used as positive and negative electron beam resists, templates for growing polymer brushes with a resolution of 20 nm, for the manufacturing of biomolecular nanopatterns, and as spacers for the preparation of stable metal/organic monolayer/metal sandwich structures.
Microspectroscopic Probing of Intracellular Structures by Observation of Infrared Linear Dichroism in Single Cells. Cellular properties and functions are closely related to cell structure. Probing intracellular structures and their dynamic nature is essential for understanding the functional characteristics of cells. Infrared (IR) microspectroscopy is an attractive tool for the investigation of biological materials and systems. Combining this technique with Polarization Modulation and employing synchrotron IR radiation allows us to perform polarization-dependent measurements with high spatial and temporal resolution. Thus, we are able to measure IR Linear Dichroism (LD) and hence determine preferred molecular orientation of distinct biochemical species in individual cells. Our goal is to gain insights into the formation and organization of the cytoskeleton in the context of cell adhesion. Using substrates with well defined surface properties and geometries we seek to control and model cell adhesion. Importantly, IR LD serves as an intrinsic marker for the preferred molecular orientation of the fibrous cytoskeletal proteins. Introduction of external stimuli such as chemicals, mechanical stress and substrate surface variation can be used to study the dynamic response and structural changes inside the cells.
Non invasive monitoring of glucose levels in mice. Before the awards of a research grant involving animals, the applicant must submit an Animal Care and Use approval to demonstrate that everything has been done to avoid unnecessary pain and discomfort. For many research applications, and particularly those utilizing diabetic animals to test either remission therapies such as islet or stem cell transplantation, immunotherapies, etc., blood must be repetitively sampled. Because the mouse is a small creature with only a small volume of blood, the number of samplings is limited. Moreover, there is considerable stress visited upon both the mouse and the person doing the sampling (either by nicking the tail or by drawing blood from a sinus behind the eye). If an inexperienced person stresses the mouse by rough handling when drawing blood, the stress itself can raise the blood glucose, making even a normal mouse appear diabetic. For rodent models of Type 2 diabetes developing complications of chronic hyperglycemia, ability to monitor blood glycemic changes accurately over time is essential.
Together with Dr. Ed Leiter of The Jackson Laboratory we work on a methodology allowing non-invasive blood glucose determination. We designed an instrument that will use ellipsoid optics to enhance the infrared radiation signal emanating from the tail of conscious mice. The basic premise is detection of the glucose-characteristic infrared vibrations exploiting the thermal gradient established by higher infrared radiation absorption in the dermis. which is vascularized, versus the epidermis which is not. Our goal is to make this instrumentation universally available.
For other projects in collaboration with the University of Heidelberg, Germany, see http://www.pci.uni-heidelberg.de/apc/
Recent publications:
Odelius M, Ogasawara H, Nordlund D, Fuchs O, Weinhardt L, Maier F, Umbach E, Heske C, Zubavichus Y, Grunze M, Denlinger JD, Pettersson LGM, Nilsson A. 2005. Ultra-fast core hole induced dynamics in water probed by X-ray emission spectroscopy. Phys Rev Let 94:227401/1-227401/4
Pertsin A, Platonov D, Grunze M. 2005. Direct computer simulation of water-mediated force between supported phospholipid membranes. J Chem Phys 122:244708
Richter GM, Stampfl U, Stampfl S, Rehnitz C, Holler S, Schnabel P, Grunze M. A new polymer concept for coating of vascular stents using PTFEP (poly(bis(trifluoroethoxy)phosphazene) to reduce thrombogenicity and late in-stent stenosis. Invest Radiolo 40:210-218
Satzl S, Henn C, Christoph P, Kurz P, Thomas F, Grenacher L, Berger I, Grunze M, Richter GM. 2005. The efficacy of poly (bis (trifluoro) ethoxy)phosphazene (PTFEP) to reduce thrombogenicity and late in-stent stenosis in a porcine coronary artery mode
Shaporenko A, Brunnbauer M, Terfort A, Johansson LSO, Grunze M, Zharnikov M. 2005. Odd-even effects in photoemission from terphenyl-substituted alkanethiolate self-assembled monolayers. Langmuir 21:4370-4375
Shaporenko A, Heister K, Ulman A, Grunze M, Zharnikov M. 2005. The effect of halogen substitution in self-assembled monolayers of 4-mercaptobiphenyls on noble metal substrates. J Phys Chem B 109:4096-4103
Tai Y, Shaporenko A, Noda H, Grunze M, Zharnikov M. 2005. Fabrication of a stable metal film on the surface of self-assembled monolayers. Adv Mat 17:1745-1749
Tai Y, Shaporenko A, Grunze M, Zharnikov M. 2005. The effect of irradiation dose in making an insulator from a self-assembled monolayer. J Phys Chem B 109:19411-19415
Tyan Y-C, Liao J-D, Jong S-B, Liao P-C, YangM-H, Chang Y-W, Klauser R, Himmelhaus M, Grunze M. 2005. Characterization of trypsin immobilized on the functionable alkylthiolate self-assembled monolayers: A preliminary application for trypsin digestion chip on protein identification using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. J Mat Sci: Mat Med 16:135-142
Wang RY, Himmelhaus M, Fick J, Herrwerth S, Eck W, Grunze M. 2005. Interaction of self-assembled monolayers of oligo(ethylene glycol)-terminated alkanethiols with water studied by vibrational sumfrequency generation (VSFG). J Chem Phys 122:164702-164706
Zubavichus Y, Shaporenko A, Grunze M, Zharnikov M. 2005. Innershell absorption spectroscopy of amino acids at all relevant absorption edges. J Phys Chem A 109:6998-7000
Zubavichus Y, Zharnikov M, Y.-J. Yang Y-J, Fuchs O, Heske C, Umbach E, Tzvetkov G, Falko P. Netzer, Grunze M. 2005. Surface chemistry of ultrathin films of histidine on gold as probed by high-resolution synchrotron photoemission. J Phys Chem B 109:884-891
Balamurugan S, Ista LK, Yan J, López GP, Himmelhaus M, Fick J, Grunze M. 2005. Reversible protein Adsorption and bioadhesion on monolayers terminated with mixtures of oligo(ethylene glycol) and methyl groups. J. Am. Chem. Soc., (2005), 127(42), 14548-9
Eck W, Küller A, Grunze M, Völkel B, Gölzhäuser A. 2005. Free-standing nanosheets from crosslinked biphenyl self-assembled monolayers. Advanced Materials, 17, 2583–2587, 2005
Noda H, Tai Y, Shaporenko A, Grunze M, Zharnikov M. 2005. Electrochemical characterizations of nickel deposition on aromatic dithiol monolayers on gold electrodes. JCPB (in print)
Anderson MG, Haraszti T, Petersen GE, Wirick S, Jacobson C, John SWM, Grunze M. 2005. Scanning transmission X-ray microscopic analysis of purified melanosomes of the mouse iris. Biophysl J (submitted)
He Q, Küller A, Grunze M, Li J. 2005. Fabrication of patterned polymer brushes with spatial and topographical controls through chemical lithgraphy and atom transfer radical polymerization. J Am Chem Soc (submitted)
Korniakov A, Küller A, Gupta P, Loos K, Spagnoli C, Ulman A, Eck W, Grunze M. 2004. Mixed self-assembled monolayers of organic thiolates on gold by electron beam irradiation. Am Chem Soc, (submitted)
Pertsin A, Grunze M. 2005. Interplay of protrusion and hydration forces between phospholipid membranes. Science (submitted)
Shaporenko A, Terfort A, Grunze M, Zharnikov M. 2005. A detailed analysis of the photoemission spectra of basic thioaromatic monolayers on noble metal substrates. J Elect Spectro Relat Phen (submitted)
Schmidt M, Schade U, Grunze M. 2005. Microspectroscopic observation of vibrational linear dichroism using polarization-modulated infrared synchrotron radiation. Infrared Phys Techn (submitted)
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