Single-molecule detector

A particle presence, number, length or concentration detector comprising:

• (a) a capacitor, comprising a first conductive plate and a second conductive plate substantially parallel to said first conductive plate, said first and second conductive plates defining an inter-plate volume having a longitudinal axis;
• and
• (b) at least two electrical contacts, connecting each of said first and second conductive plates to a capacitance measuring device;
• said capacitor being designed and constructed for allowing a determination of a presence, number or concentration of particles placed within said inter-plate volume of said capacitor, said particles being present in a fluid and having a dielectric coefficient other than a dielectric coefficient of said fluid.

A method of manufacturing a motion detector for detecting at least one particle present in a fluid and having a dielectric coefficient other than a dielectric coefficient of the fluid, the method comprising the steps of:

• (a) etching a non conductive substrate so as to provide at channel having walls;
• (b) coating said walls by a conductive material so as to provide so as to provide a first conductive plate and a second conductive plate, said second conductive plate being spaced apart from said first conductive plate, so as to define an inter-plate volume having a longitudinal axis;
• and
• (c) providing at least two electrical contacts, connecting each of said first and said second conductive plates to a capacitance measuring device.

A detector, for determining presence, number, length concentration, position and/or motion of at least one particle present in a fluid and having a dielectric coefficient other than a dielectric coefficient of the fluid, the detector comprising:

• (a) a variable-width capacitor comprising a first conductive plate and a second conductive plate having a variable distance therebetween and defining an inter-plate volume of a variable-width having a longitudinal axis;
• and
• (b) at least two electrical contacts, connecting each of said first and second conductive plates to a capacitance measuring device;
• said variable-width capacitor being designed and constructed for determination of a longitudinal position and/or monitoring a change of position along said longitudinal axis of a single conductive particle placed within said inter-plate volume of said variable-width capacitor.