Richard Bunk
Lund University
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Publication
Featured researches published by Richard Bunk.
Biochemical and Biophysical Research Communications | 2003
Richard Bunk; Jeanna Klinth; Lars Montelius; Ian A. Nicholls; P. Omling; Sven Tågerud; Alf Månsson
We have here, for the first time, used nanofabrication techniques to reproduce aspects of the ordered actomyosin arrangement in a muscle cell. The adsorption of functional heavy meromyosin (HMM) to five different resist polymers was first assessed. One group of resists (MRL-6000.1XP and ZEP-520) consistently exhibited high quality motility of actin filaments after incubation with HMM. A second group (PMMA-200, PMMA-950, and MRI-9030) generally gave low quality of motility with only few smoothly moving filaments. Based on these findings electron beam lithography was applied to a bi-layer resist system with PMMA-950 on top of MRL-6000.1XP. Grooves (100-200nm wide) in the PMMA layer were created to expose the MRL-6000.1XP surface for adsorption of HMM and guidance of actin filament motility. This guidance was quite efficient allowing no U-turns of the filaments and approximately 20 times higher density of moving filaments in the grooves than on the surrounding PMMA.
Nanotechnology | 2005
Richard Bunk; Mark Sundberg; Alf Månsson; Ian A. Nicholls; P. Omling; Sven Tågerud; Lars Montelius
Guiding motor-propelled molecules with nanoscale precision through silanized bi-channel structures
Langmuir | 2008
Petr G. Vikhorev; Natalia N. Vikhoreva; Mark Sundberg; Martina Balaz; Nuria Albet-Torres; Richard Bunk; Anders Kvennefors; Kenneth Liljesson; Ian A. Nicholls; Leif Nilsson; Pär Omling; Sven Tågerud; Lars Montelius; Alf Månsson
The interaction between cytoskeletal filaments (e.g., actin filaments) and molecular motors (e.g., myosin) is the basis for many aspects of cell motility and organization of the cell interior. In the in vitro motility assay (IVMA), cytoskeletal filaments are observed while being propelled by molecular motors adsorbed to artificial surfaces (e.g., in studies of motor function). Here we integrate ideas that cytoskeletal filaments may be used as nanoscale templates in nanopatterning with a novel approach for the production of surface gradients of biomolecules and nanoscale topographical features. The production of such gradients is challenging but of increasing interest (e.g., in cell biology). First, we show that myosin-induced actin filament sliding in the IVMA can be approximately described as persistent random motion with a diffusion coefficient (D) given by a relationship analogous to the Einstein equation (D = kT/gamma). In this relationship, the thermal energy (kT) and the drag coefficient (gamma) are substituted by a parameter related to the free-energy transduction by actomyosin and the actomyosin dissociation rate constant, respectively. We then demonstrate how the persistent random motion of actin filaments can be exploited in conceptually novel methods for the production of actin filament density gradients of predictable shapes. Because of regularly spaced binding sites (e.g., lysines and cysteines) the actin filaments act as suitable nanoscale scaffolds for other biomolecules (tested for fibronectin) or nanoparticles. This forms the basis for secondary chemical and topographical gradients with implications for cell biological studies and biosensing.
Microelectronic Engineering | 2003
Richard Bunk; Jeanna Klinth; Jenny P. Rosengren; Ian A. Nicholls; Sven Tågerud; P. Omling; Alf Månsson; Lars Montelius
In this work, we reconstructed in vitro the behavior of two motor proteins--myosin and actin--responsible for the mechanical action of muscle cells. By transferring this in vivo system to an artificial environment, we were able to study the interaction between the proteins in more detail, as well as investigating the central mechanism of force production. Nm-patterning by e-beam lithography (EBL) could restore parts of the in vivo protein order, essential for potential nanotechnological applications. Much work was put into establishing the necessary compatibility between the biological and nano-lithographical processes. A range of EBL-resists were tested for protein compatibility. One particular kind (MRL-6000.1XP) supported good actin filament motility, while another (PMMA-950) behaved in the opposite way. Taking advantage of these findings, nm-sized lines were created in a double-layer structure of the two resists. The lines were found to act as binding sites for myosin, and as rectifying guides for the linearized motion of actin filaments. Velocities around 5 µm/s were measured.
Japanese Journal of Applied Physics | 2005
Richard Bunk; Patrick Carlberg; Alf Månsson; Ian A. Nicholls; P. Omling; Mark Sundberg; Sven Tågerud; Lars Montelius
This work, for the first time, demonstrates that nano-imprinted samples, with 100 nm wide polymer lines, can act as guides for molecular motors consisting of motor proteins actin and myosin. The motor protein function was characterized using fluorescence microscopy and compared to actomyosin motility on non-structured nitrocellulose surfaces. Our results open for further use of the nano-imprint technique in the production of disposable chips for bio-nanotechnological applications and miniaturized biological test systems. We discuss how the nano-imprinted motor protein assay system may be optimized and also how it compares to previously tested assay systems involving low-resolution UV-lithography and low throughput but high-resolution electron beam lithography.
international conference on nanotechnology | 2004
Patrick Carlberg; Fredrik Johansson; Thomas Mårtensson; Richard Bunk; Marc Beck; Filip Persson; Magnus T. Borgström; S G Nilsson; Babak Heidari; M Grazcyk; Ivan Maximov; Eva-Lena Sarwe; Torbjörn G.I. Ling; Alf Månsson; Martin Kanje; Werner Seifert; Lars Samuelson; Lars Montelius
In this paper, we present a status report on how implementation of nanoimprint lithography has advanced our research. Contact guidance nerve growth experiments have so far primarily been done on micrometer-structured surfaces. We have made a stamp with 17 areas of different, submicron, line width and spacing covering a total 2.6 mm/spl times/0.45 mm. This has been imprinted, in PMMA, and consequently used in experiments to investigate how axonal outgrowth is affected by the nanopatterns. Protein interactions with nanostructured surfaces are also studied in a system exploring and controlling biomolecular motors, i.e., the muscle motor proteins actin and myosin.
Biochemical and Biophysical Research Communications | 2004
Alf Månsson; Mark Sundberg; Martina Balaz; Richard Bunk; Ian A. Nicholls; P. Omling; Sven Tågerud; Lars Montelius
Langmuir | 2006
Mark Sundberg; Richard Bunk; Nuria Albet-Torres; Anders Kvennefors; Fredrik Persson; Lars Montelius; Ian A. Nicholls; Sara Ghatnekar-Nilsson; P. Omling; Sven Tågerud; Alf Månsson
Analytical Biochemistry | 2003
Mark Sundberg; Jenny P. Rosengren; Richard Bunk; Joakim Lindahl; Ian A. Nicholls; Sven Tågerud; P. Omling; Lars Montelius; Alf Månsson
Langmuir | 2006
Mark Sundberg; Martina Balaz; Richard Bunk; Jenny Rosengren-Holmberg; Lars Montelius; Ian A. Nicholls; P. Omling; Sven Tågerud; Alf Månsson