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386 results on '"Hirtz, Michael"'

53. Locally Controlled Growth of Individual Lambda-Shaped Carbon Nanofibers

Author

Lutz, Christian, primary, Bog, Uwe, additional, Loritz, Tobias, additional, Syurik, Julia, additional, Malik, Sharali, additional, Kumar, Chethala Neelakandhan Shyam, additional, Kübel, Christian, additional, Bruns, Michael, additional, Greiner, Christian, additional, Hirtz, Michael, additional, and Hölscher, Hendrik, additional

Published
2019
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54. Attoliter Chemistry for Nano-Scale Functionalization of Graphene

Author

Hirtz, Michael, Varey, Sarah, Fuchs, Harald, and Vijayaraghavan, Aravind

Abstract

The nanoscale, multiplexed functionalization of graphene in a device array is a critical step to realize graphene-based chemical and biosensors. We demonstrate that graphene can be functionalized with submicron resolution and in well-defined locations and patterns using reaction agents in attoliter quantities, utilizing dip-pen nanolithography or microchannel cantilever spotting. Specifically, we functionalize graphene with a biotin azide using click-chemistry and demonstrate the subsequent binding of fluorescently tagged streptavidin. The technique can be scaled up to multiplex functionalize graphene devices on a wafer-scale for sensor and biomedical applications.

Published
2016
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59. “Molecular Activity Painting” : Switch-like, light-controlled perturbations inside living cells

Author

Chen, Xi, Venkatachalapathy, Muthukumaran, Kamps, Dominic, Weigel, Simone, Kumar, Ravi, Orlich, Michael, Garrecht, Ruben, Hirtz, Michael, Niemeyer, Christof M., Wu, Yao-Wen, Dehmelt, Leif, Chen, Xi, Venkatachalapathy, Muthukumaran, Kamps, Dominic, Weigel, Simone, Kumar, Ravi, Orlich, Michael, Garrecht, Ruben, Hirtz, Michael, Niemeyer, Christof M., Wu, Yao-Wen, and Dehmelt, Leif

Abstract

Acute subcellular protein targeting is a powerful tool to study biological networks. However, signaling at the plasma membrane is highly dynamic, making it difficult to study in space and time. In particular, sustained local control of molecular function is challenging due to lateral diffusion of plasma membrane targeted molecules. Here we present “Molecular Activity Painting” (MAP), a novel technology which combines photoactivatable chemically induced dimerization (pCID) with immobilized artificial receptors. The immobilization of artificial receptors by surface-immobilized antibodies blocks lateral diffusion, enabling rapid and stable “painting” of signaling molecules and their activity at the plasma membrane with micrometer precision. Using this method, we show that painting of the RhoA-myosin activator GEF-H1 induces patterned acto-myosin contraction inside living cells.

Published
2017
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60. Substrate-independent dip-pen nanolithography based on reactive coatings

Author

Hsien-Yeh Chen, Hirtz, Michael, Xiaopei Deng, Laue, Thomas, Fuchs, Harald, and Lahann, Joerg

Subjects
Nanolithography -- Analysis, Chemistry
Abstract

The various applications of the substrate- independent dip-pen nanolithography technique for the modification of the substrates are discussed. The technique is shown to be extremely beneficial for various different biotechnological applications.

Published
2010

62. Self-limiting Multiplexed Assembly of Lipid Membranes on Large-area Graphene Sensor Arrays

Author

Hirtz, Michael, Oikonomou, Antonios, Clark, Nicholas, Kim, Yong Jin, Fuchs, Harald, and Vijayaraghavan, Aravind

Subjects
National Graphene Institute, ResearchInstitutes_Networks_Beacons/national_graphene_institute, lipids (amino acids, peptides, and proteins)
Abstract

Phospholipid membranes of different functionalities weresimultaneously assembled on arrays of graphene surfaces in aparallel manner using multi-pen lipid dip-pen nanolithography.The graphene patch facilitates and restricts thespreading of lipids within itself, obviating the need to scan thewriting probes and reducing writing time. Binding studiesestablish that the lipids retain the functionality

Published
2016
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64. Influence of substrate treatment on self-organized pattern formation by Langmuir-Blodgett transfer

Author

Hirtz, Michael, Fuchs, Harald, and Lifeng Chi

Subjects
Thin films, Multilayered -- Analysis, Chemical models -- Usage, Chemicals, plastics and rubber industries
Abstract

The influence of substrates on the pattern formation by Langmuir-Blodgett (LB) transfer is examined by using silicon slides treated by different cleaning processes. The shift in the transfer pressure range for patterning is described with a model of equivalent states and also by considering the effect of microscale water films on the substrates.

Published
2008

65. Langmuir-Blodgett patterning: a bottom-up way to build mesostructures over large areas

Author

Xiaodong Chen, Lenhert, Steven, Hirtz, Michael, Nan Lu, Fuchs, Harald, and Lifeng Chi

Subjects
Thin films, Multilayered -- Chemical properties, Nanotechnology -- Research, Phospholipids -- Structure, Phospholipids -- Chemical properties, Chemistry, Science and technology
Abstract

A new paradigm Langmuir-Blodgett (LB) patterning is described for large-area patterning with mesostructured features. This method uses a simple fabrication technique to control the alignment, size, shape, and periodicity of self-organized phospholipid monolayer patterns with feature sizes down to 100 nm over surface areas of square centimeters.

Published
2007

67. Inside Back Cover: “Molecular Activity Painting”: Switch-like, Light-Controlled Perturbations inside Living Cells (Angew. Chem. Int. Ed. 21/2017)

Author

Chen, Xi, primary, Venkatachalapathy, Muthukumaran, additional, Kamps, Dominic, additional, Weigel, Simone, additional, Kumar, Ravi, additional, Orlich, Michael, additional, Garrecht, Ruben, additional, Hirtz, Michael, additional, Niemeyer, Christof M., additional, Wu, Yao-Wen, additional, and Dehmelt, Leif, additional

Published
2017
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71. Clickable Antifouling Polymer Brushes for Polymer Pen Lithography

Author

Bog, Uwe, primary, de los Santos Pereira, Andres, additional, Mueller, Summer L., additional, Havenridge, Shana, additional, Parrillo, Viviana, additional, Bruns, Michael, additional, Holmes, Andrea E., additional, Rodriguez-Emmenegger, Cesar, additional, Fuchs, Harald, additional, and Hirtz, Michael, additional

Published
2017
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73. A Versatile Microarray Platform for Capturing Rare Cells

Author

Brinkmann, Falko, Hirtz, Michael, Haller, Anna, Gorges, Tobias M., Vellekoop, Michael J., Riethdorf, Sabine, Müller, Volkmar, Pantel, Klaus, and Fuchs, Harald

Subjects
Technology, Lab-On-A-Chip Devices, Neoplasms, Humans, ddc:600, Article, Oligonucleotide Array Sequence Analysis
Abstract

Analyses of rare events occurring at extremely low frequencies in body fluids are still challenging. We established a versatile microarray-based platform able to capture single target cells from large background populations. As use case we chose the challenging application of detecting circulating tumor cells (CTCs) – about one cell in a billion normal blood cells. After incubation with an antibody cocktail, targeted cells are extracted on a microarray in a microfluidic chip. The accessibility of our platform allows for subsequent recovery of targets for further analysis. The microarray facilitates exclusion of false positive capture events by co-localization allowing for detection without fluorescent labelling. Analyzing blood samples from cancer patients with our platform reached and partly outreached gold standard performance, demonstrating feasibility for clinical application. Clinical researchers free choice of antibody cocktail without need for altered chip manufacturing or incubation protocol, allows virtual arbitrary targeting of capture species and therefore wide spread applications in biomedical sciences.

Published
2015
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78. Micropatterning for single-cell adhesion in microwells of high-density microfluidic living-cell microarrays

Author

Goossens, Katty, Hirtz, Michael, Sekula-Neuner, Sylwia, Yvanoff, Charlotte, Ielasi, Francesco, Fuchs, Harald, Willaert, Ronnie, Structural Biology Brussels, Department of Bio-engineering Sciences, and Ultrastructure

Subjects
dip-pen nanolithography, osteoblast, microfluidics, micropattern, single-cell, AFM, microwell
Abstract

A recent method to create micropatterns is dip-pen nanolithography (DPN), which is an atomic force microscopy (AFM)-based lithography technique. Micropatterns for cell adhesion (Sekula et al., 2008) can be fabricated with a feature size down to appr. 15 µm (Wu et al., 2011). The advantage of this method is that micropatterns can be written in microwells, which can be organized in an array in a microfluidic chip for high-throughput screening. Conventional ink jet methods will not allow for spot sizes that are in the desired size range for microwell printing. Printing techniques like microcontact printing (µCP) will encounter geometrical constrains when trying to print on the bottom of the well structure. In this work, we initiated the evaluation of DPN for the single-cell adhesion and growth of osteoblasts and Saccharomyces cerevisiae yeast cells, and printing of microstructures in microwells.

Published
2014

79. Dip-pen nanolithography-assisted protein crystallization

Author

Ielasi, Francesco, Hirtz, Michael, Fuchs, Harald, Willaert, Ronnie, Structural Biology Brussels, Department of Bio-engineering Sciences, and Ultrastructure

Subjects
lipid layer, protein crystallization, pen-lithography, dip-pen nanolithography, technology, industry, and agriculture, lipids (amino acids, peptides, and proteins), AFM, nanobiotechnology
Abstract

We demonstrate the use of dip-pen nanolithography (DPN) to crystallize proteins on surface localized functionalized lipid layer arrays. DOPC lipid layers, containing small amounts of biotin-DOPE lipid molecules, were printed on glass substrates and evaluated in vapor diffusion and batch crystallization screening setups, where streptavidin was used as a model protein for crystallization. Independently of the crystallization system used and the geometry of the lipid layers, nucleation of streptavidin crystals specifically occurred on the DPN-printed biotinylated structures. Protein crystallization on lipid array patches is demonstrated in a microfluidic chip, which opens the way towards high-throughput screening to find suitable nucleation and crystal growth conditions.

Published
2014

87. Multiscale Origami Structures as Interface for Cells

Author

Angelin, Alessandro, primary, Weigel, Simone, additional, Garrecht, Ruben, additional, Meyer, Rebecca, additional, Bauer, Jens, additional, Kumar, Ravi Kapoor, additional, Hirtz, Michael, additional, and Niemeyer, Christof M., additional

Published
2015
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99. Apertureless Cantilever-Free Pen Arrays for Scanning Photochemical Printing

Author

Zhou, Yu, primary, Xie, Zhuang, additional, Brown, Keith A., additional, Park, Daniel J., additional, Zhou, Xiaozhu, additional, Chen, Peng-Cheng, additional, Hirtz, Michael, additional, Lin, Qing-Yuan, additional, Dravid, Vinayak P., additional, Schatz, George C., additional, Zheng, Zijian, additional, and Mirkin, Chad A., additional

Published
2014
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