| 1. |
- Ling, TGI, et al.
(författare)
-
Fa-brication and characterization of a molecular adhesive layer for micro- and nanofabricated electrochemical electrodes
- 2003
-
Ingår i: Microelectronic Engineering. - 1873-5568. ; 67-8, s. 887-892
-
Tidskriftsartikel (refereegranskat)abstract
- In the microelectronics industry, gold electrodes on silicon dioxide are produced using an adhesive layer of chromium or titanium. This method is applicable whenever a dry environment is present. However, when such an electrode is exposed to an electrolyte a galvanic cell is formed and the less noble metal will dissolve and eventually destroy the electrode. We describe here how a monolayer of mercaptopropyl-trimethoxysilane (MPTS) can be used as an adhesive. The layer can be structured lithographically making gold electrodes in the micro- and nano-range applicable for use in electrochemistry. The properties of the MPTS layer were investigated with photoelectron microscopy, atomic force microscopy and the electrochemical performance of the gold electrodes was determined by cyclic voltammetry. (C) 2003 Elsevier Science B.V. All rights reserved.
|
|
| 2. |
- Månsson, Alf, et al.
(författare)
-
Self-organization of motor-propelled cytoskeletal filaments at topographically defined borders.
- 2012
-
Ingår i: Journal of Biomedicine and Biotechnology. - : Hindawi Limited. - 1110-7243 .- 1110-7251. ; 2012, s. Article ID: 647265-
-
Tidskriftsartikel (refereegranskat)abstract
- Self-organization phenomena are of critical importance in living organisms and of great interest to exploit in nanotechnology. Here we describe in vitro self-organization of molecular motor-propelled actin filaments, manifested as a tendency of the filaments to accumulate in high density close to topographically defined edges on nano- and microstructured surfaces. We hypothesized that this "edge-tracing" effect either (1) results from increased motor density along the guiding edges or (2) is a direct consequence of the asymmetric constraints on stochastic changes in filament sliding direction imposed by the edges. The latter hypothesis is well captured by a model explicitly defining the constraints of motility on structured surfaces in combination with Monte-Carlo simulations [cf. Nitta et al. (2006)] of filament sliding. In support of hypothesis 2 we found that the model reproduced the edge tracing effect without the need to assume increased motor density at the edges. We then used model simulations to elucidate mechanistic details. The results are discussed in relation to nanotechnological applications and future experiments to test model predictions.
|
|
| 3. |
- Bunk, Richard, et al.
(författare)
-
Actomyosin motility on nanostructured surfaces
- 2003
-
Ingår i: Biochemical and Biophysical Research Communications. - 1090-2104. ; 301:3, s. 783-788
-
Tidskriftsartikel (refereegranskat)abstract
- 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 (100-200 nm 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.
|
|
| 4. |
- Mansson, A, et al.
(författare)
-
In vitro sliding of actin filaments labelled with single quantum dots
- 2004
-
Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 314:2, s. 529-534
-
Tidskriftsartikel (refereegranskat)abstract
- We recently refined the in vitro motility assay for studies of actomyosin function to achieve rectified myosin induced sliding of actin filaments. This paves the way, both for detailed functional studies of actomyosin and for nanotechnological applications. In the latter applications it would be desirable to use actin filaments for transportation of cargoes (e.g., enzymes) between different predetermined locations on a chip. We here describe how single quantum dot labelling of isolated actin filaments simultaneously provides handles for cargo attachment and bright and photostable fluorescence labels facilitating cargo detection and filament tracking. Labelling was achieved with preserved actomyosin function using streptavidin-coated CdSe quantum dots (Qdots). These nanocrystals have several unique physical properties and the present work describes their first use for functional studies of isolated proteins outside the cell. The results, in addition to the nanotechnology developments, open for new types of in vitro assays of isolated biomolecules. (C) 2003 Elsevier Inc. All rights reserved.
|
|
| 5. |
- Beck, Marc, et al.
(författare)
-
Fabrication and characterization of a molecular adhesive layer for micro- and nanofabricated electrochemical electrodes
- 2002
-
Ingår i: 7th International Conference on Nanometer-Scale Science and Technology and 21st European Conference on Surface Science.
-
Konferensbidrag (refereegranskat)abstract
- When making nanoelectrodes for applications in liquid cells it is plausible that the less noble metal layer may be negatively affected, i.e. it will be etched away leading to very unstable conditions during operation. Here we describe a dry method to produce such a molecular layer consisting of mercaptopropyltriethoxysilane (MPTS) making it possible to controllable and reproducibly form a covalently bound monolayer of MPTS to the SiO2 surface. From Photoelectron Spectroscopy measurements we could conclude that the layer thickness corresponds to a monolayer. We have electrochemically characterized such electrodes by cyclic voltammetry. Furthermore, we have successfully patterned such layers at both micro- and nanometer scale showing the possibilities to fabricate chemically selective and active areas that may be used in various applications
|
|
| 6. |
- Bunk, Richard
(författare)
-
Creation of a Nanometer-Scale Toolbox for Molecular Motor Transport-Circuits
- 2005
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents studies of molecular motors in interaction with nm-scale structures, as well as the development of a set of tools that can be used for the construction of custom-designed nano-transportation systems. In our studies, we have used the latest nanoscale technology and combined this with advanced results from chemistry and biomedical sciences. We have succeeded in transferring biomolecules from their natural habitat to an artificial environment created on a silicon-chip. The molecules - motor proteins myosin and actin - were maintained in their fully functional state by controlling the surface morphology and chemistry of the chip environment with nm-scale precision. These proteins are nanomachines, capable of transforming chemical energy into mechanical work. Our work has been concentrated on the introduction and development of a toolbox concept. A set of nm-scale tools, or components, have been defined and created, each with their unique basic transport function. The custom-designed components have been constructed as independent building blocks that can be combined into any circuit design of for example motor-driven micro-laboratories. The designing can be performed without detailed knowledge of the underlying mechanisms, e.g. lithography or motor protein biochemistry. To some extent, the concept resembles that of micro-electronics. The key components in the toolbox have been constructed of molecular monolayers and lithographic resist. We have found that monolayers of trimethylchlorosilane can be used to make conventional semiconductor materials, such as silicon, biocompatible. Furthermore, we have created a three-dimensional resist structure on the surface of a silicon-chip, that have been used to guide the mechanical motion developed by the motor proteins. With this novel design we have reduced the degrees of freedom for the proteins so that the effective guidance precision has increased successively from millimeter-, to micrometer- and eventually nanometer scale. Principally, electron-beam lithography has been used for the fabrication of the samples, although nano-imprint lithography has also been demonstrated as a powerful tool for parallel massive production on a commercial scale. In a series of experiments we have fine-tuned and characterized the properties of each toolbox component. Tools have been developed to capture and stream the molecular motors, reroute them and to analyze them. We have also demonstrated how cargo can be attached to the filaments, and performed successful experiments with chemically-linked quantum dots.
|
|
| 7. |
- Bunk, Richard, et al.
(författare)
-
Guiding molecular motors with nano-imprinted structures
- 2005
-
Ingår i: Japanese Journal of Applied Physics. - 0021-4922. ; 44:5A, s. 3337-3340
-
Tidskriftsartikel (refereegranskat)abstract
- 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.
|
|
| 8. |
- Bunk, Richard, et al.
(författare)
-
Towards a 'nano-traffic' system powered by molecular motors
- 2003
-
Ingår i: Microelectronic Engineering. - 1873-5568. ; 67-8, s. 899-904
-
Tidskriftsartikel (refereegranskat)abstract
- 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 mum/s were measured. (C) 2003 Elsevier Science B.V. All rights reserved.
|
|
| 9. |
- Carlberg, Patrick, et al.
(författare)
-
Nanoimprint - a tool for realizing nano-bio research
- 2004
-
Ingår i: 2004 4th IEEE Conference on Nanotechnology. - 0780385365 ; , s. 199-200
-
Konferensbidrag (refereegranskat)abstract
- 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
|
|
| 10. |
- Mansson, A, et al.
(författare)
-
Actin-based molecular motors for cargo transportation in nanotechnology - Potentials and challenges
- 2005
-
Ingår i: IEEE Transactions on Advanced Packaging. - 1521-3323. ; 28:4, s. 547-555
-
Tidskriftsartikel (refereegranskat)abstract
- Here, we review the use of actin-based motors, (myosins; e.g., the molecular motor of muscle) in. nanotechnology. The review starts from the viewpoints of the molecular motors as being important devices responsible of cargo transportation in the cell and end in discussions about their employment in nanotechnological applications. First, we describe basic biophysics of the myosin motors with focus on their involvement in cargo transportation in the living cell, leading us over into a discussion about in vitro motility assays. These are biological test systems where the myosin-induced translocation of actin filaments is studied on an artificial surface outside the cell. Then follows a review about modified motility assays for production of ordered motion. Here, we discuss ours and others' work with regards to making micro- and nanostructured surfaces and channels where the position and direction of movement produced by molecular motors is controlled. In this section, we consider the role of the channel size in promoting unidirectional myosin-induced motion of actin filaments. Furthermore, we consider the usefulness of surface modifications, e.g., various silanization procedures in order to promote and hinder molecular motility, respectively. Particularly, we describe our latest test system being both morphologically and chemically nanostructured giving us unsurpassed possibilities to perform functional studies as well as extremely good spatio-temporal control. Then follows a section about nanotechnological cargo transportation systems based on the actomyosin motor system. For instance, we present results of attaching fluorescent quantum dots as cargoes to the actin filaments. In this section, we also discuss the possibilities of having cargo attachment and detachment being performed on demand. Finally, we consider the usefulness of molecular motors for lab-on-a-chip applications and the requirements for incorporating these motors in commercially viable devices. In this context, the significant potential of the actomyosin motor system to overcome traditional limitations of micro- and nanofluidics is stressed.
|
|
