Method and apparatus for measuring charge and size of single objects in a fluid
AssigneeUniversitäT ZüRich
InventorMadhavi Krishnan
Life of this patent
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Abstract
In a method for determining charge and/or size of an object (15) suspended in a fluid, the object (15) is introduced, together with the fluid, into an electrostatic trap (1) defining an electrostatic confining potential. The thermal motion of the object (15) in the fluid is observed under influence of the confining potential, and charge and/or size are determined from the observed thermal motion. In particular, the viscous drag on the object yields a measure of its size, while the stiffness of its confinement can be compared with a potential model to reveal the total charge it carries. Also disclosed are an apparatus and software for carrying out the method.
Claims15
A method for determining at least one of charge and size of an object suspended in a fluid, the method comprising:
- introducing the object, together with the fluid, into an electrostatic trap defining an electrostatic confining potential (ΔU);
- with an imaging device, observing thermal motion of the object in the fluid under influence of the confining potential (ΔU);
- and
- with an analyzing device connected to the imaging device, determining at least one of charge and size from the observed thermal motion, wherein at least one characteristic of the confining potential is determined by the analyzing device from the observed thermal motion and is compared with a potential model of the confining potential, thereby determining at least one of charge and size of the object.
An apparatus for determining at least one of size and charge of an object suspended in a fluid, the apparatus comprising:
- an electrostatic trap for receiving the object together with the fluid and for trapping the object in an electrostatic confining potential;
- an imaging device for observing thermal motion of the object under influence of the confining potential;
- and
- an analyzing device connected to the imaging device, and configured to receive information about the thermal motion from the imaging device and to determine at least one of size and charge of the object from the observed thermal motion,
- wherein the analyzing device is configured to determine at least one characteristic of the confining potential (ΔU) from the observed thermal motion and to compare the determined characteristic with a potential model to determine at least one of charge and size of the object.
An analyzing device configured to execute the steps of a computer program code, the steps of the computer program code comprising:
- receiving information from an imaging device about thermal motion of an object suspended in a fluid under influence of a confining potential in an electrostatic trap ;
- and determining at least one of charge and size of the object from the received information, by determining at least one characteristic of the confining potential (ΔU) from the received information;
- and comparing the determined characteristic with a model potential to determine at least one of the charge and size of the object.
Dependencies are inferred from the claim text.