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4. Facilitating an International Research Experience Focused on Applied Nanotechnology and Surface Chemistry for American Undergraduate Students Collaborating with Mentors at a German Educational and Research Institution

Author

Wilson, Christina, Hirtz, Michael, Levkin, Pavel A., Sutlief, Arin L., and Holmes, Andrea E.

Abstract

The "International Research Experience for Students (IRES)" at Doane University (DU) located in Crete, Nebraska, exposed undergraduate science, technology, engineering, and mathematics (STEM) students to international research at the Karlsruhe Institute of Technology (KIT) in Germany. The international collaboration team included three undergraduate researchers per year from DU, one faculty member and one postdoctoral fellow from DU, two faculty mentors at KIT, and several graduate, post-doctoral, and technical staff at KIT. Prior to departure to Germany, the students received extensive research training, as well as culture and language preparation from the mentors at DU. While in Germany, the students received an in-depth orientation to Karlsruhe, Germany, Europe, the research setting at KIT, and the international collaborators. The eight week summer projects over three years involved nanolithography, nano- to microsized array fabrication, organic synthesis using click chemistry, and surface modifications for sensing and other biomedical research applications. When the students returned from Germany, they continued to conduct research at DU and train other undergraduate students using the expertise acquired from KIT. The DU research students, including the IRES scholars, learned oral and written communication skills. They presented their KIT and DU research results at weekly seminars and at local and national meetings. An external assessment firm evaluated the program, the students, and mentors on a yearly basis before and after the summer research. This enabled all participants to continuously improve the learning objectives and the program execution including three program adjustments implemented in year 2 or 3. The survey data shows that the IRES program provided an enriching experience for the students in research and international culture and established a successful base of collaboration for mentors.

Published
2019
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5. Printing Technologies for Integration of Electronic Devices and Sensors

Author

Baby, Tessy Theres, Marques, Gabriel Cadilha, Neuper, Felix, Singaraju, Surya Abhishek, Garlapati, Suresh, von Seggern, Falk, Kruk, Robert, Dasgupta, Subho, Sykora, Benedikt, Breitung, Ben, Sukkurji, Parvathy Anitha, Bog, Uwe, Kumar, Ravi, Fuchs, Harald, Reinheimer, Timo, Mikolajek, Morten, Binder, Joachim R., Hirtz, Michael, Ungerer, Martin, Koker, Liane, Gengenbach, Ulrich, Mishra, Nilesha, Gruber, Patric, Tahoori, Mehdi, Hagmann, Jasmin Aghassi, von Seggern, Heinz, Hahn, Horst, Sidorenko, Anatolie, editor, and Hahn, Horst, editor

Published
2020
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6. Diamond Nanophotonic Circuits Functionalized by Dip-pen Nanolithography

Author

Rath, Patrik, Hirtz, Michael, Lewes-Malandrakis, Georgia, Brink, Dietmar, Nebel, Christoph, and Pernice, Wolfram H. P.

Subjects
Physics - Optics
Abstract

Nanophotonic circuits based on polished diamond thin films are prepared. These circuits cover a wide wavelength range across the entire visible spectrum. Integrated devices are surface functionalized site-specifically and in parallel using dip-pen nanolithography with a minimum linewidth of 100 nm. Multicolor fluorescence is coupled into the underlying photonic network using microring resonators and grating structures., Comment: Advanced Optical Materials 2014

Published
2014
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7. Rapid Capture of Cancer Extracellular Vesicles by Lipid Patch Microarrays

Author

Liu, Hui‐Yu, Kumar, Ravi, Zhong, Chunting, Gorji, Saleh, Paniushkina, Liliia, Masood, Ramsha, Wittel, Uwe A., Fuchs, Harald, Nazarenko, Irina, Hirtz, Michael, Liu, Hui‐Yu, Kumar, Ravi, Zhong, Chunting, Gorji, Saleh, Paniushkina, Liliia, Masood, Ramsha, Wittel, Uwe A., Fuchs, Harald, Nazarenko, Irina, and Hirtz, Michael

Abstract

Extracellular vesicles (EVs) contain various bioactive molecules such as DNA, RNA, and proteins, and play a key role in the regulation of cancer progression. Furthermore, cancer‐associated EVs carry specific biomarkers and can be used in liquid biopsy for cancer detection. However, it is still technically challenging and time consuming to detect or isolate cancer‐associated EVs from complex biofluids (e.g., blood). Here, a novel EV‐capture strategy based on dip‐pen nanolithography generated microarrays of supported lipid membranes is presented. These arrays carry specific antibodies recognizing EV‐ and cancer‐specific surface biomarkers, enabling highly selective and efficient capture. Importantly, it is shown that the nucleic acid cargo of captured EVs is retained on the lipid array, providing the potential for downstream analysis. Finally, the feasibility of EV capture from patient sera is demonstrated. The demonstrated platform offers rapid capture, high specificity, and sensitivity, with only a small need in analyte volume and without additional purification steps. The platform is applied in context of cancer‐associated EVs, but it can easily be adapted to other diagnostic EV targets by use of corresponding antibodies.

Published
2024

8. Surface-Patterned DNA Origami Rulers Reveal Nanoscale Distance Dependency of the Epidermal Growth Factor Receptor Activation

Author

Mayer, Ivy, primary, Karimian, Tina, additional, Gordiyenko, Klavdiya, additional, Angelin, Alessandro, additional, Kumar, Ravi, additional, Hirtz, Michael, additional, Mikut, Ralf, additional, Reischl, Markus, additional, Stegmaier, Johannes, additional, Zhou, Lu, additional, Ma, Rui, additional, Nienhaus, Gerd Ulrich, additional, Rabe, Kersten S., additional, Lanzerstorfer, Peter, additional, Domínguez, Carmen M., additional, and Niemeyer, Christof M., additional

Published
2024
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9. Stability of Immobilized Chemosensor‐Filled Vesicles on Anti‐Fouling Polymer Brush Surfaces.

Author

Yang, Wenwu, Xiao, Jiangxiong, Yang, Bingquan, Mathew, George, Schäfer, Andreas H., and Hirtz, Michael

Subjects
REACTIVE polymers, DRUG discovery, SMALL molecules, MEMBRANE permeability (Biology), HIGH temperatures, POLYMERS, POLYMERSOMES, POLYMERIC membranes
Abstract

The characterization of phospholipid membrane permeability for small molecules is crucial for many applications in drug discovery and biomedical research in general. Here, chemosensor‐laden vesicles offer an attractive platform for permeability assays. In this work, the stability of immobilized chemosensor‐filled vesicles is explored on anti‐fouling polymer brush surfaces for potential use in monitoring small molecule membrane permeability. The study focuses on the development of a method for immobilizing sensor‐loaded vesicles into arbitrary patterns on surfaces and characterizing their stability under changing temperatures and compositions. As substrate to enable intact, long‐term stable vesicle immobilization reactive polymer brushes with anti‐fouling properties are used. Utilizing microchannel cantilever spotting, biotin moieties are introduced on the polymer brush surface, enabling stable tethering of vesicles through streptavidin‐biotin interactions. The immobilized vesicles are monitored through fluorescence microscopy for their response to analytes under changing environmental parameters and vesicle composition. A higher stability of immobilized vesicles compared to free‐floating ones is observed, with permeability only at elevated temperatures. By tuning vesicle compositions, permeability at lower temperatures can be raised again. Overall, the study provides insights into a novel approach for vesicle immobilization, showcasing the potential of surface‐bound vesicles for applications in microfluidic systems and as biosensors in various assays. [ABSTRACT FROM AUTHOR]

Published
2024
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10. Printed Electronic Devices and Systems for Interfacing with Single Cells up to Organoids.

Author

Saghafi, Mahsa K., Vasantham, Srivatsan K., Hussain, Navid, Mathew, George, Colombo, Federico, Schamberger, Barbara, Pohl, Eric, Marques, Gabriel Cadilha, Breitung, Ben, Tanaka, Motomu, Bastmeyer, Martin, Selhuber‐Unkel, Christine, Schepers, Ute, Hirtz, Michael, and Aghassi‐Hagmann, Jasmin

Subjects
ELECTRONIC systems, ELECTRONIC equipment, BIOELECTRONICS, LASER printing, ORGANOIDS, DIGITAL printing
Abstract

The field of bioelectronics with the aim to contact cells, cell clusters, biological tissues and organoids has become a vast enterprise. Currently, it is mainly relying on classical micro‐ and nanofabrication methods to build devices and systems. Very recently the field is highly pushed by the development of novel printable organic, inorganic and biomaterials as well as advanced digital printing technologies such as laser and inkjet printing employed in this endeavor. Recent advantages in alternative additive manufacturing and 3D printing methods enable interesting new routes, in particular for applications requiring the incorporation of delicate biomaterials or creation of 3D scaffold structures that show a high potential for bioelectronics and building of hybrid bio‐/inorganic devices. Here the current state of printed 2D and 3D electronic structures and related lithography techniques for the interfacing of electronic devices with biological systems are reviewed. The focus lies on in vitro applications for interfacing single cell, cell clusters, and organoids. Challenges and future prospects are discussed for all‐printed hybrid bio/electronic systems targeting biomedical research, diagnostics, and health monitoring. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Printing Technologies for Integration of Electronic Devices and Sensors

Author

Baby, Tessy Theres, primary, Marques, Gabriel Cadilha, additional, Neuper, Felix, additional, Singaraju, Surya Abhishek, additional, Garlapati, Suresh, additional, von Seggern, Falk, additional, Kruk, Robert, additional, Dasgupta, Subho, additional, Sykora, Benedikt, additional, Breitung, Ben, additional, Sukkurji, Parvathy Anitha, additional, Bog, Uwe, additional, Kumar, Ravi, additional, Fuchs, Harald, additional, Reinheimer, Timo, additional, Mikolajek, Morten, additional, Binder, Joachim R., additional, Hirtz, Michael, additional, Ungerer, Martin, additional, Koker, Liane, additional, Gengenbach, Ulrich, additional, Mishra, Nilesha, additional, Gruber, Patric, additional, Tahoori, Mehdi, additional, Hagmann, Jasmin Aghassi, additional, von Seggern, Heinz, additional, and Hahn, Horst, additional

Published
2020
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13. Nanoscale Confinement of Dip‐Pen Nanolithography Written Phospholipid Structures on CuZr Nanoglasses.

Author

Vasantham, Srivatsan K., Boltynjuk, Evgeniy, Nandam, Sree Harsha, Berganza Eguiarte, Eider, Fuchs, Harald, Hahn, Horst, and Hirtz, Michael

Subjects
NANOLITHOGRAPHY, CELL membranes, CELL anatomy, MEMBRANE lipids, BIOMATERIALS, PHOSPHOLIPIDS
Abstract

Nanoglasses have attracted considerable interest among material scientists due to their novel and surprising properties. However, there is still a significant gap in understanding how nanoglasses interact with biomaterials and their effects on living cells. Previous cell studies have reported indications of possible proliferation effects, but a comprehensive understanding of differentiating nanoglass influences from distinct material or topography effects is yet to be established. In this study, the interaction between nanoglass surfaces and phospholipids, which are fundamental components of cell membranes, is investigated. The findings reveal a unique stabilizing effect exhibited by nanoglasses on structures created using lipid dip‐pen nanolithography, preventing their spreading over the surface ("confinement"). This discovery suggests that nanoglasses can potentially influence the structure of cell membranes, providing a conceivable mechanism for how nanoglasses may impact cell behavior. [ABSTRACT FROM AUTHOR]

Published
2024
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31. Diamond Surfaces with Clickable Antifouling Polymer Coating for Microarray-Based Biosensing

Author

Kumar, Ravi, Yang, Bingquan, Barton, Jan, Stejfova, Miroslava, Schäfer, Andreas, König, Meike, Knittel, Peter, Cigler, Petr, Hirtz, Michael, and Publica

Abstract

Diamond enables the construction of various (bio)sensors, including those with quantum-based detection. However, bare diamond interfaces are susceptible to unspecific adhesion of proteins and other macromolecules from biological media or complex samples. This impairs selectivity in biosensing, leads to low signal-to-noise ratio in fluorescence-based applications, and introduces the need for blocking steps in incubation protocols. Here, a stable, protein-repellent, and clickable reactive polymer coating is introduced, abolishing unspecific protein adhesion while concurrently enabling covalent immobilization of functional compounds as recognition elements. The polymer coating has two segments, an antifouling poly(N-(2-hydroxypropyl) methacrylamide) and an alkyne-terminated poly(propargyl methacrylamide) providing the click functionality. The antifouling properties and click-reactivity of the polymers are demonstrated by selective protein binding assays on micropatterns written by microchannel cantilever spotting (µCS). The assays demonstrated the successful functionalization of both diamond and glass surfaces and the excellent antifouling properties of the polymer coating. The coating procedure is compatible with oxidized diamond surfaces thus well-suitable for diamond-based quantum technology. The results can directly impact applications of diamond materials in optically detected quantum sensing or fluorescence sensing in general. The polymer functionalization can also be used for any case where highly specific interaction with low fouling is desired.

Published
2022
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39. Multiplexed Covalent Patterns on Double‐Reactive Porous Coating.

Author

Das, Supriya, Kumar, Ravi, Yang, Bingquan, Bag, Sudipta, Sauter, Eric, Hussain, Navid, Hirtz, Michael, and Manna, Uttam

Subjects
INK-jet printing, SURFACE coatings, POROUS materials, SUPERHYDROPHOBIC surfaces, FLUOROPHORES, ADDITION reactions
Abstract

We have conceptualized and demonstrated an approach based on the combination of hydrophobicity, a substrate‐independent dip coating as porous material with double residual chemical reactivities for implementing multiplexed, miniaturized and unclonable bulk‐infused patterns of different fluorophores following distinct reaction pathways. The embedded hydrophobicity (∼102°) restricted the unwanted spreading of beaded aqueous ink on the coating. The constructions of micropatterns on porous dip‐coating via ink‐jet printing or microchannel cantilever spotting offered orthogonal read‐out and remained readable even after removal of the exterior of the coating. [ABSTRACT FROM AUTHOR]

Published
2022
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42. Thioacetate‐Based Initiators for the Synthesis of Thiol‐End‐Functionalized Poly(2‐oxazoline)s

Author

Gil Alvaradejo, Gabriela, primary, Glassner, Mathias, additional, Kumar, Ravi, additional, Trouillet, Vanessa, additional, Welle, Alexander, additional, Wang, Yangxin, additional, Rosa, Victor R., additional, Sekula‐Neuner, Sylwia, additional, Hirtz, Michael, additional, Hoogenboom, Richard, additional, and Delaittre, Guillaume, additional

Published
2020
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45. Scanner‐Based Capillary Stamping

Author

Hou, Peilong, primary, Kumar, Ravi, additional, Oberleiter, Bastian, additional, Kohns, Richard, additional, Enke, Dirk, additional, Beginn, Uwe, additional, Fuchs, Harald, additional, Hirtz, Michael, additional, and Steinhart, Martin, additional

Published
2020
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46. Synergies between Surface Microstructuring and Molecular Nanopatterning for Controlling Cell Populations on Polymeric Biointerfaces

Author

Díaz Lantada, Andrés, primary, Kumar, Ravi, additional, Guttmann, Markus, additional, Wissmann, Markus, additional, Schneider, Marc, additional, Worgull, Matthias, additional, Hengsbach, Stefan, additional, Rupp, Florian, additional, Bade, Klaus, additional, Hirtz, Michael, additional, and Sekula-Neuner, Sylwia, additional

Published
2020
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48. Writing Behavior of Phospholipids in Polymer Pen Lithography (PPL) for Bioactive Micropatterns

Author

Angelin, Alessandro, Bog, Uwe, Kumar, Ravi, Niemeyer, Christof M., and Hirtz, Michael

Subjects
Life sciences, biology, scanning probe lithography, supported lipid bilayers, PPL, In-house research, biomimetic membranes, Article, lcsh:QD241-441, polymer pen lithography, lcsh:Organic chemistry, ddc:570, lipids (amino acids, peptides, and proteins), supported lipid membranes, DPN, phospholipids
Abstract

Lipid-based membranes play crucial roles in regulating the interface between cells and their external environment, the communication within cells, and cellular sensing. To study these important processes, various lipid-based artificial membrane models have been developed in recent years and, indeed, large-area arrays of supported lipid bilayers suit the needs of many of these studies remarkably well. Here, the direct-write scanning probe lithography technique called polymer pen lithography (PPL) was used as a tool for the creation of lipid micropatterns over large areas via polymer-stamp-mediated transfer of lipid-containing inks onto glass substrates. In order to better understand and control the lipid transfer in PPL, we conducted a systematic study of the influence of dwell time (i.e., duration of contact between tip and sample), humidity, and printing pressure on the outcome of PPL with phospholipids and discuss results in comparison to the more often studied dip-pen nanolithography with phospholipids. This is the first systematic study in phospholipid printing with PPL. Biocompatibility of the obtained substrates with up to two different ink compositions was demonstrated. The patterns are suitable to serve as a platform for mast cell activation experiments.

Published
2019
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49. Evaluation of Microfluidic Ceiling Designs for the Capture of Circulating Tumor Cells on a Microarray Platform

Author

Liu, Hui‐Yu, primary, Koch, Claudia, additional, Haller, Anna, additional, Joosse, Simon A., additional, Kumar, Ravi, additional, Vellekoop, Michael J., additional, Horst, Ludwig J., additional, Keller, Laura, additional, Babayan, Anna, additional, Failla, Antonio Virgilio, additional, Jensen, Jana, additional, Peine, Sven, additional, Keplinger, Franz, additional, Fuchs, Harald, additional, Pantel, Klaus, additional, and Hirtz, Michael, additional

Published
2019
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