D. Böcherer, R. Montazeri, Y. Li, S. Tisato, L. Hambitzer, D. Helmer, Decolorization of Lignin for High-Resolution 3D Printing of High Lignin-Content Composites, Advanced Science, 2024, 202406311. | Link
N. Nekoonam, F. Dreher, F. Mayoussi, P. Zhu, R. Thomann, R. Montazeri, S. Bhagwat, L. Hambitzer, D. Helmer, Enhancing Photoswitchable Wetting Properties of Hydrophobic Porous Spiropyran Copolymer Surfaces Through Surface Roughness Engineering, Adv. Mater. Interfaces 2024, 2400396. | Link
D. Böcherer, Y. Li, C. Rein, S. Franco Corredor, P. Hou, D. Helmer, High-Resolution 3D Printing of Dual-Curing Thiol-Ene/Epoxy System for Fabrication of Microfluidic Devices for Bioassays, Advanced Functional Materials, 2024, 2401516. | Link
S. Tisato, G. Vera, A. Mani, T. Chase, D. Helmer, An easy-to-build, accessible volumetric 3D printer based on a liquid crystal display for rapid resin development, Additive Manufacturing, 87, 2024, 104232. | Link
D. Böcherer, Y. Li, S. Kluck, N. Nekoonam, P. Zhu, B.E. Rapp, F. Kotz-Helmer, D. Helmer, COLOR3D – Multicolored 3D printing of wood composites by submicron structuring, Additive Manufacturing, 10.1016/j.addma.2023.103723. | Link
N. Nekoonam, G. Vera, A. Goralczyk, F. Mayoussi, P. Zhu, D. Böcherer, A. Shakeel, D. Helmer, Controllable Wetting Transitions on Photoswitchable Physical Gels, ACS Appl. Mater. Interfaces, 2023, 15, 22, 27234–27242. | Link
F. Mayoussi, A. Usama, N. Nekoonam, I. Knauer, D. Böcherer, B. E. Rapp, D. Helmer, Influence of Parylene F Coatings on the Wetting Properties of Soft Polydimethylsiloxane (PDMS), Materials, 2023, 16(5), 1938 | Link | Link
A. Goralczyk, S. Bhagwat, F. Mayoussi, N. Nekoonam, K. Sachsenheimer, P. Hou, F. Kotz-Helmer, D. Helmer, B. E. Rapp, Application of Micro/Nanoporous Fluoropolymers with Reduced Bioadhesion in Digital Microfluidics, Nanomaterials, 2022, 12(13), 2201 | Link
P. Pezeshkpour, K. Sachsenheimer, A. Goralczyk, F. Mayoussi, M. Mader, F. Kotz-Helmer, D. Helmer, B. E. Rapp, A Real-Time Capacitive Sensor to Detect the Stability of Salvinia Layers on Porous Superhydrophobic Polymers Under Shear, Adv. Mater. Technol., 2022, 2200287 | Link
S. Bhagwat, C.O'Brien, A. Hamza, S. Sharma, C. Rein, M. Sanjaya, D. Helmer, F. Kotz-Helmer, P. Pezeshkpour, B.E.Rapp, An On-Chip Liquid Metal Plug Generator, Adv. Mater. 2022, 2201469 | Link
A. Goralczyk, M. Zhu, F. Mayoussi, M. Lallemang, M. Tschaikowsky, A. Warmbold, S. Caliaro, F. Tauber, B. N. Balzer, F. Kotz-Helmer, D. Helmer, B. E. Rapp, Study of repellence on polymeric surfaces with two individually adjustable pore hierarchies, Chem. Eng. J. 2022, 437, 135287 | Link
S. Franco Corredor, F. Mayoussi, M. Luitz, A. Kick, A. Goralczyk, D. Böcherer, G. Vera, D. Helmer, F. Kotz-Helmer, B. E. Rapp, A Polystyrene Photoresin for Direct Lithography of Microfluidic Chips. Adv. Mater. Technol. 2022, 2200084 | Link
M. Mader, L. Hambitzer, P. Schlautmann, S. Jenne, C. Greiner, F. Hirth, D. Helmer, F. Kotz-Helmer, B.E. Rapp: "Melt-Extrusion-Based Additive Manufacturing of Transparent Fused Silica Glass", Adv. Sci., 2021, 8, 2103180 | Link
F. Mayoussi, E. H. Doeven, A. Kick, A. Goralczyk, Y. Thomann, P. Risch, R. M. Guijt, F. Kotz, D. Helmer, B. E. Rapp: "Facile fabrication of micro-/nanostructured, superhydrophobic membranes with adjustable porosity by 3D printing", Journal of Materials Chemistry A, 2021 | Link
Marco Beaumont, Remy Tran, Grace Vera, Dennis Niedrist, Aurelie Rousset, Ronan Pierre, V. Prasad Shastri, and Aurelien Forget: “Hydrogel-Forming Algae Polysaccharides: From Seaweed to Biomedical Applications”, Biomacromolecules 2021 22 (3), 1027-1052 | Link
Merve Kuzucu, Grace Vera, Marco Beaumont, Sascha Fischer, Pan Wei, V. Prasad Shastri, and Aurelien Forget: “Extrusion-Based 3D Bioprinting of Gradients of Stiffness, Cell Density, and Immobilized Peptide Using Thermogelling Hydrogels”, ACS Biomaterials Science & Engineering 2021 7 (6), 2192-2197 | Link
Engemeann, I. Rink, M. F. Kilb, M. Hungsberg, D. Helmer, K. Schmitz: "Cell-based actin polymerization assay to analyze chemokine inhibitors", Journal of Pharmacological and Toxicological Methods, 2021 | Link
Luitz, M., Lunzer, M., Goralczyk, A., Mader, M., Bhagwat, S., Warmbold, A., Helmer, D., Kotz, F., Rapp, B. E., High Resolution Patterning of an Organic–Inorganic Photoresin for the Fabrication of Platinum Microstructures. Adv. Mater. 2021, 33, 2101992 | Link
Kotz, A. S. Quick, P. Risch, T. Martin, T. Hoose, M. Thiel, D. Helmer, B. E. Rapp: “Two‐Photon Polymerization of Nanocomposites for the Fabrication of Transparent Fused Silica Glass Microstructures”, Advanced Materials, 33, 9, 2006341, 2021 | Link
Mader, O. Schlatter, B. Heck, A. Warmbold, A. Dorn, H. Zappe, P. Risch, D. Helmer, F. Kotz, B. E. Rapp: “High-throughput injection molding of transparent fused silica glass”, Science, 2021 | Link
Steffen Wiedmann, Benjamin Kerscher, Caroline Lienert, David Böcherer, Rolf Muelhaupt: “Tailoring Poly(2-oxazoline)-Based Polymeric Ionic Liquids as Thermoresponsive Molecular Brushes and Programmable Dispersants for Silver Nanoparticles”, Macromolecules, 2020 | Link
Helmer, B. E. Rapp: "Divide and Print", Nature Materials, 19, 131-133, 2020 | Link
Kotz, M. Mader, N. Dellen, P. Risch, A. Kick, D. Helmer, B. E. Rapp: “Fused deposition modeling of microfluidic chips in polymethylmethacrylate”, Micromachines, 11(9), 873, 2020. | Link
Keller, J. Bruchmann, T. Sollich, C. Richter, R. Thelen, F. Kotz, T. Schwartz, D. Helmer, B. E. Rapp: "Study of Biofilm Growth on Slippery Liquid-Infused Porous Surfaces Made from Fluoropor", ACS Applied Materials & Interfaces, 11, 4480-4487, 2019 | Link
F. Kotz, P. Risch, K. Arnold, S. Sevim, J. Puigmarti-Luis, A. Quick, M. Thiel, A. Hrynevich, P. Dalton, D. Helmer, B. E. Rapp: “Fabrication of arbitrary three-dimensional suspended hollow microstructures in transparent fused silica glass”, Nature Communication, 10, 1439, 2019 | Link
Risch, D. Helmer, F. Kotz, B. E. Rapp: "Analytical solution of the time-dependent microfluidic poiseuille flow in rectangular channel cross-sections and its numerical implementation in Microsoft Excel", Biosensors, 9(2), 67, 2019 | Link
Sachsenheimer, C. Richter, D. Helmer, F. Kotz, B. E. Rapp: "A Nontoxic Battery with 3D-printed housing for on-demand operation of microcontrollers in microfluidic sensors", Micromachines, 10, 599, 2019 | Link
T. M. Nargang, R. Dierkes, J. Bruchmann, N. Keller, K. Sachsenheimer, C. Lee-Thedieck, F. Kotz, D. Helmer and B. E. Rapp: "Photolithographic structuring of soft, extremely foldable and autoclavable hydrophobic barriers in paper", Analytical Methods, 10, 4028-4035, 2018 | Link
Rivas A.L., Vera G., Palacios V., Cornejo M., Rigail A., Solórzano G.: “Phase Transformation of Amorphous Rice Husk Silica”. In: Muruganant M., Chirazi A., Raj B. (eds) Frontiers in Materials Processing, Applications, Research and Technology. Springer, Singapore (2018) | Link
Kotz, P. Risch, D. Helmer, B. E. Rapp: “Highly Fluorinated Methacrylates for Optical 3D Printing of Microfluidic Devices”, Micromachines, 9, 3, 15, 2018 (invited) | Link
Helmer, N. Keller, F. Kotz, F. Stolz, C. Greiner, T. M. Nargang, K. Sachsenheimer, B. E. Rapp: „Transparent, abrasion-insensitive superhydrophobic coatings for real-world applications”, Nature Scientific Reports, 7, 1, 15078, 2017. | Link
Richter, F. Kotz, N. Keller, T. M. Nargang, K. Sachsenheimer, D. Helmer, B. E. Rapp: “An Analytical Solution to Neumann-Type Mixed Boundary Poiseuille Microfluidic Flow in Rectangular Channel Cross-Sections (Slip/No-Slip) Including a Numerical Technique to Derive It”, Journal of Biomedical Science and Engineering, 10, 205-219, 2017 | Link
Helmer, A. Voigt, S. Wagner, N. Keller, K. Sachsenheimer, F. Kotz, T. M. Nargang, B. E. Rapp: "Suspended Liquid Subtractive Lithography: One-step generation of 3D channel geometries in viscous curable polymer matrices", Nature Scientific Reports 7, 7387, 2017 | Link
Kotz, K. Arnold, W. Bauer, D. Schild, N. Keller, K. Sachsenheimer, T. M. Nargang, C. Richter, D. Helmer, B. E. Rapp: "Three-dimensional Printing of Transparent Fused Silica Glass", Nature, 544, 337-339, 2017 | Link | Media Coverage | Video
Richter, K. Sachsenheimer, N. Keller, T. M. Nargang, D. Helmer, F. Kotz, B. E. Rapp: "An individual addressable and latchable actuator array for microfluidic systems", Microfluid Nanofluid 20:130, 2016. | Link
Richter, F. Kotz, S. Giselbrecht, D. Helmer, B. E. Rapp: "Numerics made easy: solving the Navier–Stokes equation for arbitrary channel cross-sections using Microsoft Excel", Biomedical Microdevices 18:52, 2016 | Link
Helmer, K. Brahm, C. Helmer, J. S. Wack, G. Brenner-Weiss, K. Schmitz: "Two-channel image analysis method for the screening of OBOC libraries", Analytical Methods, 2016 | Link
Kotz, K. Plewa, W. Bauer, N. Schneider, N. Keller, T. Nargang, D. Helmer, K. Sachsenheimer, M. Schäfer, M. Worgull, C. Greiner, C. Richter, B. E. Rapp: “Liquid Glass: A Facile Soft Replication Method for Structuring Glass”, Advanced Materials, 28, 4646-4650, 2016 | Link | Media Coverage
Keller, T. M. Nargang, M. Runck, F. Kotz, A. Striegel, K. Sachsenheimer, D. Klemm, K. Länge, M. Worgull, C. Richter, D. Helmer, B. E. Rapp: "Tacky Cyclo Olefin Copolymer: A biocompatible bonding technique for the fabrication of microfluidic channels in COC", Lab Chip, 16, 1561-1564, 2016 | Link
M. Nargang, M. Runck, D. Helmer, B. E. Rapp: "Functionalization of paper using photobleaching: a fast and convenient method for creating paper-based assays with colorimetric and fluorescent readout", Engineering in Life Sciences, 2016 | Link
Helmer, I. Rink, J. A. R. Dalton, K. Brahm, M. Jöst, T. M. Nargang, W. Blum, P. Wadhwani, G. Brenner-Weiss, B. E. Rapp, J. Giraldo, K. Schmitz: “Rational design of a peptide capture agent for CXCL8 based on a model of the CXCL8:CXCR1 complex”, RSC Advances, 5, 25657-25668, 2015 | Link
Rink, J. Rink, D. Helmer, D. Sachs, K. Schmitz: "A Haptotaxis Assay for Leukocytes Based on Surface-Bound Chemokine Gradients", Journal of Immunology, 2015 | Link
M. Nargang, L. Brockmann, P. Nikolov, D. Schild, D. Helmer, N. Keller, K. Sachsenheimer, E. Wilhelm, L. Pires, M. Dirschka, A. Kolew, M. Worgull, S. Giselbrecht, C. Neumann, B. E. Rapp: “Liquid polystyrene: a room-temperature photocurable soft lithography compatible pour-and-cure-type polystyrene”, Lab Chip (special issue “Emerging Investigators"), 14, 2698-2708, 2014 | Link
Reviews
Kotz, P. Risch, D. Helmer, B. E. Rapp: “High-performance materials for 3D printing in chemical synthesis applications”, Advanced Materials (invited), 2019 | Link
Books and Book chapters
Kotz, D. Helmer, B. E. Rapp: “Emerging Technologies and Materials for High-Resolution 3D Printing of Microfluidic Chips”, book chapter within "Advances in Biochemical Engineering/Biotechnology", Springer Nature, 2020 | Link
Kotz, D. Helmer, B. E. Rapp: “3D Printing of Transparent Glasses”, book chapter within "3D Printing of Optical Components", 169-184, Springer, 2020 | Link
Helmer, K. Schmitz: „Peptides and Peptide Analogs to Inhibit Protein-Protein Interactions“, Böldicke (ed.) Protein Targeting – Prediction, Selection and Activity of Specific Inhibitors, Springer, 2015 | Link
Helmer: “Synthesis and Test of Peptides and Peptoids for the Inhibition of Cytokines”, Cuvillier Verlag, Göttingen, 2015 | Link
Conference Contributions
S. Tisato, G. Vera, D. Helmer, "Development of an extrusion-based printing platform for volumetric “MatrixPrint” printing", VAM21 - Volumetric Additive Manufacturing workshop, 2021
G. Vera, S. Tisato, P. Risch, F. Kotz, B. E. Rapp, D. Helmer: “Supporting Matrices for extrusion based volumetric “MatrixPrint” printing of polymers, glass and metal”, talk, Volumetric Additive Manufacturing VAM21 workshop, 2021
Andres Rigail-Cedeño, Daniel F. Schmidt, Grace Vera, Monica Chavez, Yesenia Pacheco, and Mercedes Alava: "Elastomeric bio-based epoxy/clay nanocomposites", AIP Conference Proceedings 2205, 020043 (2020) | Link
A Kick, D Helmer, F Kotz, B Rapp:“Generation of multi-level microstructures using a wavelength-selective photoresist and mask-less grayscale lithography”, talk, SPIE Photonics West, San Francisco, USA, 2020
Kotz, P. Risch, M. Thiel, A. Quick, D. Helmer, B. E. Rapp: “Sacrificial Template Replication: Fabrication of arbitrary 3D microfluidic channels in transparent fused silica glass”, talk, SPIE Photonics West, San Francisco, USA, 2020
Helmer, F. Kotz, B. E. Rapp: „Suspended liquid subtractive lithography: printing three dimensional channels directly into uncured polymeric matrices”, talk, SPIE Photonics West, San Francisco, 2019
Risch, F. Kotz, D. Helmer, B. E. Rapp: „3D printing of highly fluorinated methacrylates for the rapid prototyping of transparent and chemically-resistant microfluidic devices”, talk, SPIE Photonics West, San Francisco, 2019
M. Nargang, R. Dierkes, J. Bruchmann, N. Keller, K. Sachsenheimer, F. Kotz, D. Helmer, B. E. Rapp: „Structuring unbreakable and autoclavable hydrophobic barriers in paper via direct printing and mask-based photolithography”, talk, SPIE Photonics West, San Francisco, 2019
Kotz, P. Risch, K. Arnold, D. Helmer, B. E. Rapp: “Next generation 3D printing - The emergence of enabling materials”, talk, SPIE Defence and Security, Berlin, Germany, 2018 | Link
Kotz, A. Striegel, N. Schneider, P. Risch, M. Worgull, D. Helmer, B. E. Rapp: "High-throughput polymer molding of transparent fused silica microfluidic chips", poster, 22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Kaohsiung, Taiwan, 2018
Risch, F. Kotz, D. Helmer, B. E. Rapp: "3D printing of microfluidic glass reactors", poster, 22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Kaohsiung, Taiwan, 2018
Risch, F. Kotz, D. Helmer, B. E. Rapp: "3D printing of highly fluorinated methacrylates for the fabrication of transparent and chemically resistant microfluidic devices", poster, 22nd International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Kaohsiung, Taiwan, 2018
Kotz, A. Striegel, N. Schneider, M. Worgull, D. Helmer, B. E. Rapp: „High-throughput structuring of fused silica glass“; talk, MNE, Kopenhagen, 2018
Helmer: "Suspended Liquid Subtractive Lithography - Fabrication of three-dimensional microchannels by the immersion of "liquid threads"", talk, Microfluidics in the Upper Rhine Valley, IS2M Mulhouse 2018
Kotz, D. Helmer, B. E. Rapp: "Additive manufacturing of microfluidic glass chips", talk, SPIE Photonics West, San Francisco, USA, 2018 | Link
Helmer, A. Voigt, S. Wagner, N. Keller, K. Sachsenheimer, F. Kotz, T. M. Nargang, B. E. Rapp: "Additive manufacturing of microfluidic glass chips", talk, SPIE Photonics West, San Francisco, USA, 2018
Helmer, A. Voigt, B. E. Rapp: "Suspended Liquid Subtractive Lithography (SLSL) – 3D printing of microfluidic structures directly into PDMS", 21st International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Savannah, USA, 2017
Kotz, D. Helmer, B. E. Rapp: "3D printing of microfluidic devices in highly fluorinated perfluoropolyethers (PFPE)", poster, 21st International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Savannah, USA, 2017
M. Nargang, F. Kotz, N. Keller, D. Helmer, B. E. Rapp: “Rapid structuring of proteins on filter paper using lithography”, talk, SPIE Photonics West, San Francisco, USA, 2017 | Link
Helmer, A. Voigt, S. Wagner, B. E. Rapp: "Rapid printing in PDMS – fused deposition modeling (FDM) meets microfluidics", talk, 20th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Dublin, Ireland, 2016
M. Nargang, E. Wilhelm, F. Kotz, D. Helmer, B. E. Rapp: “UV-light based structuring of unbreakable hydrophobic barriers on commonly used papers”, poster, 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Gyeongju, Korea, 2015
Helmer, N. Keller, B. E. Rapp: “Photolithographic structuring of highly fluorinated polymers for the fabrication of microfluidic chips”, talk, 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), Gyeongju, Korea, 2015
Helmer, N. Keller, B. E. Rapp: “Reversibly Photoswitchable Hydrophilic/Hydrophobic Surfaces”, talk, ECOSS, Barcelona, Spain, 2015
Kotz, N. Keller, T.M. Nargang, K. Sachsenheimer, M. Dirschka, D. Helmer, C. Neumann, Bastian E. Rapp: “Computer aided microfluidics (CAMF): from 3D model to physical structures in less than a day”, talk, Euroanalysis, Bordeaux, France, 2015
M. Nargang, L. Brockmann, P. Nikolov, D. Schild, D. Helmer, N. Keller, M. Dirschka, A. Kolew, M. Worgull, S. Giselbrecht, C. Neumann, B. E. Rapp: “‘Liquid polystyrene’: a photocurable liquid polystyrene prepolymer as new material for microfluidic prototyping”, poster, 18th International Conference on Miniaturized Systems for Chemistry and Life Sciences (µTAS), San Antonio, USA, 2014
Patents
E. Rapp, D. Helmer, C. Richter, N. Keller: “Highly fluorinated nanostructured polymer foams for producing super-repellent surface”, WO2018065094A1, 2016 | Link
E. Rapp, D. Helmer, C. Richter, N. Keller: "Hochfluorierte nanostrukturierte Polymerschäume zur Herstellung superabweisender Oberflächen", DE102016012001A1, 2016 | Link
E. Rapp, D. Helmer, A. Voigt: "Method and apparatus for generating a three-dimensional structure in a matrix“, EP3305495A1, 2016 | Link
E. Rapp, D. Helmer, A. Voigt: "Verfahren und Vorrichtung zur Erzeugung einer dreidimensionalen Struktur in einer Matrix", DE102016219192, 2016 | Link
Miscellaneous
Helmer, B. E. Rapp: "Superabweisende Oberflächen - Die Entwicklung eines superhydrophoben Werkstoffs", GIT Labor-Fachzeitschrift, 2018 | Link
Questions?
Do you have questions concerning this project or are you interested in collaborations, industry projects or seeking a PhD, intern or student position? Please get into contact with us.
