Methods for microfluidic aspirating and dispensing
First Claim
1. A method for aspirating a fluid from a source using an aspirate-dispense system including a drop-on-demand valve in fluid communication with a direct current fluid source, comprising the steps of:
- reducing the hydraulic pressure within said system by opening said valve of said system to dispense system liquid into a non-target position;
dipping a tube of said system in said fluid source; and
creating a reduced pressure in said system to aspirate a quantity of said fluid of said source into said tube of said system.
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Accused Products
Abstract
A method for actively controlling the hydraulic pressure within an aspirate-dispense system for aspirating and dispensing precise and/or predetermined quantities of fluid or reagent. The method provides an efficient pressure compensation scheme to achieve the optimal pressures for aspirating and dispensing. The optimized pressures are achieved by a series of operations of a positive displacement pump and a drop-on-demand valve of the aspirate-dispense system. Advantageously, the method increases process speed, improves reliability and accuracy, and reduces dilution and wastage of reagent.
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Citations
39 Claims
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1. A method for aspirating a fluid from a source using an aspirate-dispense system including a drop-on-demand valve in fluid communication with a direct current fluid source, comprising the steps of:
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reducing the hydraulic pressure within said system by opening said valve of said system to dispense system liquid into a non-target position;
dipping a tube of said system in said fluid source; and
creating a reduced pressure in said system to aspirate a quantity of said fluid of said source into said tube of said system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for aspirating a fluid from a source, comprising the steps of:
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reducing the hydraulic pressure within an aspirate-dispense system by withdrawing a predetermined quantity of system fluid from a feedline of said system;
dipping a tube of said system in said fluid source; and
adjusting positive displacement means of said system so that a reduced pressure is created in said system to aspirate a quantity of said fluid of said source into said tube of said system. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for dispensing a fluid onto a target using an aspirate-dispense system including a drop-on-demand valve in fluid communication with a direct current fluid source, comprising the steps of:
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pressurizing said system by adjusting said direct current fluid source of said system while maintaining said valve of said system in a closed position to build hydraulic pressure within said system to a generally steady state and/or predetermined value;
selecting a desired flow rate of fluid to be dispensed from a tube of said system onto said target; and
operating said direct current fluid source and said valve of said system to dispense precise and/or predetermined quantities of said fluid onto said target. - View Dependent Claims (19, 20, 21, 22, 23, 24)
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25. A method for aspirating fluid from a source and dispensing said fluid onto a target using an aspirate-dispense system including a drop-on-demand valve in hydraulic communication with a direct current fluid source, comprising the steps of:
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adjusting said system by opening said valve of said system to dispense system liquid into a non-target position so that the hydraulic pressure within said system is reduced;
dipping a tube of said system in said fluid source;
creating a reduced pressure in said system by operating said direct current fluid source to aspirate a quantity of said fluid of said source into said tube of said system;
pressurizing said system by adjusting said direct current fluid source of said system while maintaining said valve in a closed position to build hydraulic pressure within said system to a generally steady state value; and
actuating said direct current fluid source and said valve of said system to dispense precise and/or predetermined quantities of said fluid onto said target. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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- 34. A method for adjusting the hydraulic pressure of an aspirate-dispense system after a purge operation, comprising the step of adjusting said system by venting a drop-on-demand valve of said system to dispense system liquid into a non-target position so that the hydraulic pressure within said system is reduced to a predetermined and/or generally steady state value.
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36. An apparatus for aspirating and/or dispensing predetermined quantities of a fluid, comprising:
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a dispenser including a drop-on-demand valve adapted to be opened and closed at a predetermined frequency and/or duty cycle;
a direct current fluid source in fluid communication with said dispenser for metering predetermined quantities of said fluid to or from said dispenser;
one or more pressure sensors placed intermediate said dispenser and said direct current fluid source and/or at said dispenser for monitoring the hydraulic pressure within said apparatus;
whereby, actuations of said valve and/or said direct current fluid source provide pressure compensation prior to aspirate and/or dispense functions by reducing or raising the hydraulic pressure within said apparatus to a predetermined and/or generally steady state pressure. - View Dependent Claims (37, 38)
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39. A hydraulic system for dispensing precise quantities of a fluid, comprising:
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a dispenser including a drop-on-demand valve adapted to be opened and closed at a predetermined frequency and/or duty cycle;
a direct current fluid source in fluid communication with said dispenser for metering predetermined quantities of said fluid to said dispenser;
the output fluid flow rate (Qn) of said hydraulic system being substantially in accordance with a transfer function having the form;
with a characteristic equation given by;
and a gain K given by;
where, Qt is the input fluid flow rate provided by said direct current fluid source, Rt is the flow resistance, C is the elastic capacitance, τ
is the inertial or inductive time constant, and s is the Laplacian variable.
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Specification