This part of the project is expected to produce a prototype molecular This part of the project is expected to produce a prototype molecular magnetic switch.  Whilst, in a real device, the precise details of how it might function will depend, to some degree, on its application, as well as the large number of variables during development, certain key aspects of the model device can be described.

The prototype device will consist of a three dimensional silicon structure, specifically machined to allow movement of the DNA and coupled magnetic beads in a channel, a liquid delivery system for the motor fuel and Si-, or fluorescence-based, detection systems.

The device will have some form of liquid delivery system, probably based on microfluidics, which will provide input to the device of buffers, DNA, molecular motor components and caged, or, normal ATP as fuel; although these components can be added at separate stages and pre-assembling the switch will be possible.  However, this part of the device could also involve a diffusion mechanism allowing ATP to enter a pre-assembled switch from the surrounding material.

The active area of the switch will, in all probability, comprise a covered channel etched in silicon (surface-coated as appropriate) large enough for the DNA strand and magnetic particle (sub-micron width).  At one end of the groove, there will be a system for DNA attachment (likely to involve covalent chemical attachment; although, a non-covalent repetitive attachment would allow easier recycling of the contents by washing in the manner used for Biacore surface plasmon resonance systems) and an entry point from the microfluidics system.  The nature of the DNA attachment to the surface, will be a significant development feature of this project.

A magnetic control device will be incorporated at the other end of the channel.  This will involve some form of controllable magnetic field generator, which can provide sufficient magnetic force to ‘stretch-out’ the DNA (c.f. a magnetic tweezer set-up).  This will be connected to external controlling system and will allow re-setting of the switch.

The magnetic-field detector device, placed part way along the channel, will be some form of solid-state device for detection of the magnetic bead as it passes the detector.  Output from this device will allow switching of adjacent silicon-based electronics.

Finally, the channel, covered with a translucent cover, can be located in the evanescent field of an epifluorescent microscope, for visualisation of fluorophores on the DNA, as they pass through this field.

Whilst, in a real device, the precise details of how it might function will depend, to some degree, on its application, as well as the large number of variables during development, certain key aspects of the model device can be described.

The prototype device will consist of a three dimensional silicon structure, specifically machined to allow movement of the DNA and coupled magnetic beads in a channel, a liquid delivery system for the motor fuel and Si-, or fluorescence-based, detection systems.

 

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