| 1. |
- Beck, Marc, et al.
(author)
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Fabrication and characterization of a molecular adhesive layer for micro- and nanofabricated electrochemical electrodes
- 2002
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In: 7th International Conference on Nanometer-Scale Science and Technology and 21st European Conference on Surface Science.
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Conference paper (peer-reviewed)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
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| 2. |
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| 3. |
- Bunk, Richard, et al.
(author)
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Actomyosin motility on nanostructured surfaces
- 2003
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In: Biochemical and Biophysical Research Communications. - 1090-2104. ; 301:3, s. 783-788
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Journal article (peer-reviewed)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.
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| 4. |
- Bunk, Richard
(author)
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Creation of a Nanometer-Scale Toolbox for Molecular Motor Transport-Circuits
- 2005
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Doctoral thesis (other academic/artistic)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.
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| 5. |
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| 6. |
- Bunk, Richard, et al.
(author)
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Guiding molecular motors with nano-imprinted structures
- 2005
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In: Japanese Journal of Applied Physics. - 0021-4922. ; 44:5A, s. 3337-3340
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Journal article (peer-reviewed)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.
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| 7. |
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| 8. |
- Bunk, Richard, et al.
(author)
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Guiding motor-propelled molecules with nanoscale precision through silanized bi-channel structures
- 2005
-
In: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 16:6, s. 710-717
-
Journal article (peer-reviewed)abstract
- We report on the design and fabrication of a channel structure for high precision guidance and achieving excellent confinement properties for motor-propelled molecular shuttles. The techniques used to manufacture the channel structure are mainly e-beam lithography and selective monolayer functionalization. The structure consists of two lateral layers of concentric channels on a SiO2 surface made biocompatible with the molecular motors. The quality and advantages of the design are demonstrated by experiments using the motor proteins actin and myosin. The special channel geometry leads to stable biochemical conditions with full motor protein functionality. ATP is sufficiently supplied to all parts of the structure by dedicated service channels, as is the venting of ADP and P-i (inorganic phosphorus). Channels of different widths (100-700 nm) and shapes are fabricated and measurements made on them.
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| 9. |
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| 10. |
- Bunk, Richard, et al.
(author)
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Towards a 'nano-traffic' system powered by molecular motors
- 2003
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In: Microelectronic Engineering. - 1873-5568. ; 67-8, s. 899-904
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Journal article (peer-reviewed)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.
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| 11. |
- Carlberg, Patrick, et al.
(author)
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Nanoimprint - a tool for realizing nano-bio research
- 2004
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In: 2004 4th IEEE Conference on Nanotechnology. - 0780385365 ; , s. 199-200
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Conference paper (peer-reviewed)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
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| 12. |
- Goncalves, Dulce, 1968-, et al.
(author)
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Cultural aspects of organizational agility affecting digital innovation
- 2020
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In: Journal of Entrepreneurship, Management, and Innovation. - Nowy Targ : Fundacja Cognitione. - 2299-7075 .- 2299-7326. ; 16:4, s. 13-46
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Journal article (peer-reviewed)abstract
- The purpose of this study is to understand how the cultural aspects of organizational agility affect digital innovation capability. In the context of increasing demand for fast-paced digital innovation, organizational agility becomes strategically crucial for large incumbent companies to increase their competitiveness. The literature on organizational agility shows that incumbents, with their vast access to resources, still can have limited ability to innovate and respond to change. This is in sharp contrast to startups, who sometimes are impressively innovative despite their very limited resources. Sometimes the incumbents are even outcompeted and disrupted by startups because of their ability to embrace change, and rapidly seize new business opportunities. However, we know little about why some incumbents are not able to use their resources efficiently for digital innovation and why some smaller startups can transcend these resource limitations. In this context, we find that cultural aspects are especially crucial as enablers for organizational agility in digital innovation. We designed a comparative study to investigate the differences in the influence of culture on organizational agility; and how it hinders or enables digital innovation, at both incumbent firms and startups in the automotive industry. We applied a qualitative research approach and selected semi-structured interviews as our main research method. The Competing Values Framework was used as a tool to categorize different cultures that affect organizational agility, but also to identify how and when tensions between values supported or hampered the organizations’ ability to innovate. Our findings show that, while a blend of Hierarchy and Market cultures inhibited the innovation capability, Clan and Adhocracy cultures promoted innovation. In our sample, the incumbents predominantly adhered to the first two cultures, while the startups typically belonged to the second group. The most successful startups were even able to create a combination of Clan and Adhocracy cultures — a concept we here term ‘Agile culture.’ This culture allowed them to reach a beneficial state of digital innovation growth. When it comes to the implications for research and practice, we found the need to analyze the role of culture for organizational agility; and how to utilize culture as an asset to enable digital innovation growth. One contribution is the identification of ‘Agile culture’ that is an amalgamation of Clan and Adhocracy culture. The value agile culture creates when applied, enables organizational agility, which can enhance digital innovation capability.
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| 13. |
- Gonçalves, Dulce, 1968-, et al.
(author)
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How co-creation supports digital innovation in automotive startups
- 2021
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In: ECIS 2021. - Illinois : Association for Information Systems. - 9781733632560
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Conference paper (peer-reviewed)abstract
- Co-creation is an essential aspect of organizational agility enabling organizations to gain digital in- novation capabilities, such as support in developing critical peripheral services or attracting talents and investors. Co-creation is especially essential for startups because of their limited resources. It fosters organizations to learn and innovate across company boundaries to remain competitive. Little is known about how startups apply co-creation to support their digital innovation initiatives. This paper presents a qualitative study of eight automotive startups, based on 22 semi-structured interviews. We applied the prediction and control framework as an analytic lens and identified three key advantages of co-creation. Embracing co-creation in ecosystems increases startups' resource capacity and speed for digital innovation. We concluded that automotive startups that apply visionary and transformative logic were found to have a better ability to lead digital innovation in a controlled way and attract wanted talents and actors.
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| 14. |
- Gonçalves, Dulce, 1968-, et al.
(author)
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How Digital Tools Align with Organizational Agility and Strengthen Digital Innovation in Automotive Startups
- 2022
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Conference paper (peer-reviewed)abstract
- Digital tools can be an enabler for automotive startups to strengthen their digital innovation capability. Still, few empirical studies describe how automotive startups apply digital tools to do this. Digital innovation capability is essential for survival in a volatile global digital marketplace. Therefore, we conducted a qualitative study based on 23 interviews with nine global automotive startups to understand how they apply digital tools to strengthen their digital innovation. The results showed that automotive startups use cloud services almost exclusively for their business. We conclude that startups choose to use digital tools as SaaS to strengthen their organizational agility and digital innovation initiatives. It harmonizes with their agile culture, effectively enabling innovation collaborations between employees internally and with external actors enabling rapidness to market. SaaS providers' startup programs enabled startups to remain focused on their innovation initiatives and not worry about scalability since the solutions scaled from the start. © 2021 Elsevier B.V. All rights reserved.
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| 15. |
- Goncalves, Dulce, 1968-, et al.
(author)
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The Influence of Cultural Values on Organizational Agility
- 2019
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In: AMCIS 2019 Proceedings. - : Association for Information Systems. - 9780996683180 ; , s. 1-10
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Conference paper (peer-reviewed)abstract
- Organizational agility, a firm’s ability to manage dynamic change, has become strategically important for companies in their innovation work. In this context cultural aspects are especially important, as they can both support and hamper organizational agility. Differences can generate innovation ability but they can also create conflicts between competing value systems, thus reducing the firm’s ability to develop organizational agility to support innovation processes. We conducted a comparative study in incumbent firms and startups in the automotive industry to identify the influence of entrepreneurial cultural values on organizational agility. The Competing Values Framework was applied to identify the relationship between cultural values and organizational agility. The result shows that cultural differences affect the companies ability to develop organizational agility for innovation work. In particular incumbents struggled to enable a change towards organizational agility. We found that startups integrated Clan and Adhocracy into an agile culture, which enabled continuous innovation growth.
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| 16. |
- Haghighi, Mona, et al.
(author)
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A Comparison of Rule-based Analysis with Regression Methods in Understanding the Risk Factors for Study Withdrawal in a Pediatric Study
- 2016
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
-
Journal article (peer-reviewed)abstract
- Regression models are extensively used in many epidemiological studies to understand the linkage between specific outcomes of interest and their risk factors. However, regression models in general examine the average effects of the risk factors and ignore subgroups with different risk profiles. As a result, interventions are often geared towards the average member of the population, without consideration of the special health needs of different subgroups within the population. This paper demonstrates the value of using rule-based analysis methods that can identify subgroups with heterogeneous risk profiles in a population without imposing assumptions on the subgroups or method. The rules define the risk pattern of subsets of individuals by not only considering the interactions between the risk factors but also their ranges. We compared the rule-based analysis results with the results from a logistic regression model in The Environmental Determinants of Diabetes in the Young (TEDDY) study. Both methods detected a similar suite of risk factors, but the rule-based analysis was superior at detecting multiple interactions between the risk factors that characterize the subgroups. A further investigation of the particular characteristics of each subgroup may detect the special health needs of the subgroup and lead to tailored interventions.
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| 17. |
- Ling, TGI, et al.
(author)
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Fa-brication and characterization of a molecular adhesive layer for micro- and nanofabricated electrochemical electrodes
- 2003
-
In: Microelectronic Engineering. - 1873-5568. ; 67-8, s. 887-892
-
Journal article (peer-reviewed)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.
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| 18. |
- Mansson, A, et al.
(author)
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Actin-based molecular motors for cargo transportation in nanotechnology - Potentials and challenges
- 2005
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In: IEEE Transactions on Advanced Packaging. - 1521-3323. ; 28:4, s. 547-555
-
Journal article (peer-reviewed)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.
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| 19. |
- Mansson, A, et al.
(author)
-
In vitro sliding of actin filaments labelled with single quantum dots
- 2004
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In: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 314:2, s. 529-534
-
Journal article (peer-reviewed)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.
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| 20. |
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| 21. |
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| 22. |
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| 23. |
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| 24. |
- Månsson, Alf, et al.
(author)
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Self-organization of motor-propelled cytoskeletal filaments at topographically defined borders.
- 2012
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In: Journal of Biomedicine and Biotechnology. - : Hindawi Limited. - 1110-7243 .- 1110-7251. ; 2012, s. Article ID: 647265-
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Journal article (peer-reviewed)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.
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| 25. |
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| 26. |
- Sundberg, Mark, et al.
(author)
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Actin filament guidance on a chip: Toward high-throughput assays and lab-on-a-chip applications
- 2006
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 22:17, s. 7286-7295
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Journal article (peer-reviewed)abstract
- Biological molecular motors that are constrained so that function is effectively limited to predefined nanosized tracks may be used as molecular shuttles in nanotechnological applications. For these applications and in high-throughput functional assays (e. g., drug screening), it is important that the motors propel their cytoskeletal filaments unidirectionally along the tracks with a minimal number of escape events. We here analyze the requirements for achieving this for actin filaments that are propelled by myosin II motor fragments (heavy meromyosin; HMM). First, we tested the guidance of HMM-propelled actin filaments along chemically defined borders. Here, trimethylchlorosilane (TMCS)-derivatized areas with high-quality HMM function were surrounded by SiO2 domains where HMM did not bind actin. Guidance along the TMCS-SiO2 border was almost 100% for filament approach angles between 0 and 20 degrees but only about 10% at approach angles near 90 degrees. A model (Clemmens, J.; Hess, H.; Lipscomb, R.; Hanein, Y.; Bohringer, K. F.; Matzke, C. M.; Bachand, G. D.; Bunker, B. C.; Vogel, V. Langmuir 2003, 19, 10967-10974) accounted for essential aspects of the data and also correctly predicted a more efficient guidance of actin filaments than previously shown for kinesin- propelled microtubules. Despite the efficient guidance at low approach angles, nanosized (< 700 nm wide) TMCS tracks surrounded by SiO2 were not effective in guiding actin filaments. Neither was there complete guidance along nanosized tracks that were surrounded by topographical barriers (walls and roof partially covering the track) unless there was also chemically based selectivity between the tracks and surroundings. In the latter case, with dually defined tracks, there was close to 100% guidance. A combined experimental and theoretical analysis, using tracks of the latter type, suggested that a track width of less than about 200-300 nm is sufficient at a high HMM surface density to achieve unidirectional sliding of actin filaments. In accord with these results, we demonstrate the long- term trapping of actin filaments on a closed-loop track (width < 250 nm). The results are discussed in relation to lab-on-a-chip applications and nanotechnology-assisted assays of actomyosin function.
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| 27. |
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| 28. |
- Sundberg, Mark, et al.
(author)
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Selective spatial localization of actomyosin motor function by chemical surface patterning
- 2006
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 22:17, s. 7302-7312
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Journal article (peer-reviewed)abstract
- We have previously described the efficient guidance and unidirectional sliding of actin filaments along nanosized tracks with adsorbed heavy meromyosin (HMM; myosin II motor fragment). In those experiments, the tracks were functionalized with trimethylchlorosilane (TMCS) by chemical vapor deposition (CVD) and surrounded by hydrophilic areas. Here we first show, using in vitro motility assays on nonpatterned and micropatterned surfaces, that the quality of HMM function on CVD-TMCS is equivalent to that on standard nitrocellulose substrates. We further examine the influences of physical properties of different surfaces (glass, SiO2, and TMCS) and chemical properties of the buffer solution on motility. With the presence of methylcellulose in the assay solution, there was HMM-induced actin filament sliding on both glass/SiO2 and on TMCS, but the velocity was higher on TMCS. This difference in velocity increased with decreasing contact angles of the glass and SiO2 surfaces in the range of 20-67 degrees (advancing contact angles for water droplets). The corresponding contact angle of CVD-TMCS was 81 degrees. In the absence of methylcellulose, there was high-quality motility on TMCS but no motility on glass/SiO2. This observation was independent of the contact angle of the glass/SiO2 surfaces and of HMM incubation concentrations (30-150 mu g mL(-1)) and ionic strengths of the assay solution (20-50 mM). Complete motility selectivity between TMCS and SiO2 was observed for both nonpatterned and for micro- and nanopatterned surfaces. Spectrophotometric analysis of HMM depletion during incubation, K/EDTA ATPase measurements, and total internal reflection fluorescence spectroscopy of HMM binding showed only minor differences in HMM surface densities between TMCS and SiO2/glass. Thus, the motility contrast between the two surface chemistries seems to be attributable to different modes of HMM binding with the hindrance of actin binding on SiO2/glass.
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| 29. |
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| 30. |
- Sundberg, M, et al.
(author)
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Silanized surfaces for in vitro studies of actomyosin function and nanotechnology applications
- 2003
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In: Analytical Biochemistry. - : Elsevier BV. - 1096-0309 .- 0003-2697. ; 323:1, s. 127-138
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Journal article (peer-reviewed)abstract
- We have previously shown that selective heavy meromyosin (HMM) adsorption to predefined regions of nanostructured polymer resist surfaces may be used to produce a nanostructured in vitro motility assay. However, actomyosin function was of lower quality than on conventional nitrocellulose films. We have therefore studied actomyosin function on differently derivatized glass surfaces with the aim to find a substitute for the polymer resists. We have found that surfaces derivatized with trimethylchlorosilane (TMCS) were superior to all other surfaces tested, including nitrocellulose. High-quality actin filament motility was observed up to 6 days after incubation with HMM and the fraction of motile actin filaments and the velocity of smooth sliding were generally higher on TMCS than on nitrocellulose. The actomyosin function on TMCS-derivatized glass and nitrocellulose is considered in relation to roughness and hydrophobicity of these surfaces. The results suggest that TMCS is an ideal substitute for polymer resists in the nanostructured in vitro motility assay. Furthermore, TMCS derivatized glass also seems to offer several advantages over nitrocellulose for HMM adsorption in the ordinary in vitro motility assay. (C) 2003 Elsevier Inc. All rights reserved.
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| 31. |
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| 32. |
- Vikhorev, Petr, et al.
(author)
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Diffusion dynamics of motor driven transport: gradient production and self-organization of surfaces.
- 2008
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 24:23, s. 13509-13517
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Journal article (peer-reviewed)abstract
- 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.
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