Climbing Rates of Microtubules Propelled by Dynein after Collision with Microfabricated Walls

Ashikari, Norihiko; Shitaka, Y.; Fujita, K.; Kojima, Hiroaki; Oiwa, Kazuhiro; Sakaue, Hiroyuki; Takahagi, Takayuki; Suzuki, Hitoshi

doi:10.1143/jjap.51.02bl03

Cited by 4 publications

(1 citation statement)

References 35 publications

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“…Several important steps towards a functional molecular motor driven diagnostic device have also been realized (reviewed in [8-13]) such as: (i) attachment of antibodies to cytoskeletal microtubule [14] and actin filament [15] shuttles, followed by molecular motor-driven transportation of analytes (viruses, protein antigens etc.) bound to the antibodies, (ii) nano/microfabrication of devices for guided transportation of the motor propelled shuttles to concentrate analytes at a detector site [6,7,16-18] and (iii) long-term storage of ready-to-use devices without loss of activity [19-21]. …”

Section: Introductionmentioning

confidence: 99%

Magnetic capture from blood rescues molecular motor function in diagnostic nanodevices

et al. 2013

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BackgroundIntroduction of effective point-of-care devices for use in medical diagnostics is part of strategies to combat accelerating health-care costs. Molecular motor driven nanodevices have unique potentials in this regard due to unprecedented level of miniaturization and independence of external pumps. However motor function has been found to be inhibited by body fluids.ResultsWe report here that a unique procedure, combining separation steps that rely on antibody-antigen interactions, magnetic forces applied to magnetic nanoparticles (MPs) and the specificity of the actomyosin bond, can circumvent the deleterious effects of body fluids (e.g. blood serum). The procedure encompasses the following steps: (i) capture of analyte molecules from serum by MP-antibody conjugates, (ii) pelleting of MP-antibody-analyte complexes, using a magnetic field, followed by exchange of serum for optimized biological buffer, (iii) mixing of MP-antibody-analyte complexes with actin filaments conjugated with same polyclonal antibodies as the magnetic nanoparticles. This causes complex formation: MP-antibody-analyte-antibody-actin, and magnetic separation is used to enrich the complexes. Finally (iv) the complexes are introduced into a nanodevice for specific binding via actin filaments to surface adsorbed molecular motors (heavy meromyosin). The number of actin filaments bound to the motors in the latter step was significantly increased above the control value if protein analyte (50–60 nM) was present in serum (in step i) suggesting appreciable formation and enrichment of the MP-antibody-analyte-antibody-actin complexes. Furthermore, addition of ATP demonstrated maintained heavy meromyosin driven propulsion of actin filaments showing that the serum induced inhibition was alleviated. Detailed analysis of the procedure i-iv, using fluorescence microscopy and spectroscopy identified main targets for future optimization.ConclusionThe results demonstrate a promising approach for capturing analytes from serum for subsequent motor driven separation/detection. Indeed, the observed increase in actin filament number, in itself, signals the presence of analyte at clinically relevant nM concentration without the need for further motor driven concentration. Our analysis suggests that exchange of polyclonal for monoclonal antibodies would be a critical improvement, opening for a first clinically useful molecular motor driven lab-on-a-chip device.

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Section: Introductionmentioning

confidence: 99%

Magnetic capture from blood rescues molecular motor function in diagnostic nanodevices

et al. 2013

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Ultrafast molecular motor driven nanoseparation and biosensing

Lard

Siethoff

Kumar

et al. 2013

Biosensors and Bioelectronics

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Portable biosensor systems would benefit from reduced dependency on external power supplies as well as from further miniaturization and increased detection rate. Systems built around self-propelled biological molecular motors and cytoskeletal filaments hold significant promise in these regards as they are built from nanoscale components that enable nanoseparation independent of fluidic pumping. Previously reported microtubule-kinesin based devices are slow, however, compared to several existing biosensor systems. Here we demonstrate that this speed limitation can be overcome by using the faster actomyosin motor system. Moreover, due to lower flexural rigidity of the actin filaments, smaller features can be achieved compared to microtubule-based systems, enabling further miniaturization. Using a device designed through optimization by Monte Carlo simulations, we demonstrate extensive myosin driven enrichment of actin filaments on a detector area of less than 10 μm², with a concentration half-time of approximately 40 s. We also show accumulation of model analyte (streptavidin at nanomolar concentration in nanoliter effective volume) detecting increased fluorescence intensity within seconds after initiation of motor-driven transportation from capture regions. We discuss further optimizations of the system and incorporation into a complete biosensing workflow.

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Understanding the Guiding of Kinesin/Microtubule-Based Microtransporters in Microfabricated Tracks

Ishigure

Nitta

2014

Langmuir

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Microtransporters using cargo-laden microtubules propelled by kinesin motors are attractive for numerous applications in nanotechnology. To improve the efficiency of transport, the movement of microtubules must be guided by microfabricated tracks. However, the mechanisms of the guiding methods used are not fully understood. Here, using computer simulation, we systematically studied the guiding of such microtransporters by three different types of guiding methods: a chemical boundary, a physical barrier, and their combination. The simulation reproduced the probabilities of guiding previously observed experimentally for the three methods. Moreover, the simulation provided further insight into the mechanisms of guiding, which overturn previous assumptions and models.

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Climbing Rates of Microtubules Propelled by Dynein after Collision with Microfabricated Walls

Cited by 4 publications

References 35 publications

Magnetic capture from blood rescues molecular motor function in diagnostic nanodevices

Magnetic capture from blood rescues molecular motor function in diagnostic nanodevices

Ultrafast molecular motor driven nanoseparation and biosensing

Understanding the Guiding of Kinesin/Microtubule-Based Microtransporters in Microfabricated Tracks

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